samedi 4 juillet 2020

Unscheduled correction of the ISS orbit











ROSCOSMOS - Russian Vehicles patch.

July 4, 2020

International Space Station (ISS). Image Credit: NASA

Flight Control Center TsNIImash (part of the State Corporation "Roskosmos") July 3, 2020 at 18:53 Moscow time carried out an unscheduled correction of the orbit of the International Space Station to avoid a possible collision with space debris. All operations were completed in full accordance with the calculations of Russian ballistic service specialists.

For this maneuver, the engines of the Progress MS-14 cargo ship were used, which is docked to the aggregate compartment of the Zvezda module of the ISS Russian segment. They worked for about 100 seconds and informed the station a speed increment of 0.5 m/s. As a result, the orbit altitude of the ISS increased, according to preliminary data, by 900 meters.


Image above: Space station astronauts photographed the glowing thrusters of a Progress spacecraft during a 14-minute firing that raised the space station's orbit by almost two miles. Image Credit: NASA.

Currently, the crew of the long-term expedition ISS-63, consisting of cosmonauts Roscosmos Anatoly Ivanishin and Ivan Wagner, as well as NASA astronauts Christopher Cassidy, Douglas Hurley and Robert Benken, are working on the planned program. The situation in low Earth orbit is under constant control of the Mission Control Centers in Korolev and in Houston (USA).

Related articles:

Progress MS-14 will correct the orbit of the ISS
http://orbiterchspacenews.blogspot.com/2020/06/progress-ms-14-will-correct-orbit-of-iss.html

ROSCOSMOS Press Release: https://www.roscosmos.ru/28767/

Images (mentioned), , Text, Credits: ROSCOSMOS/NASA/Orbiter.ch Aerospace/Roland Berga.

Best regards, Orbiter.ch

vendredi 3 juillet 2020

Welcome anyons! Physicists find best evidence yet for long-sought 2D structures












Quantum Physics logo.

July 3, 2020

The ‘quasiparticles’ defy the categories of ordinary particles and herald a potential way to build quantum computers.


Image above: The ‘pyjama stripe’ interference pattern denotes the presence of anyons in an electronic system. Image Credits: James Nakamura and Michael Manfra.

Physicists have reported what could be the first incontrovertible evidence of the existence of unusual particle-like objects called anyons, first proposed more than 40 years ago. Anyons are latest addition to a growing family of phenomena called quasiparticles, which are not elementary particles but collective excitations of many electrons in solid devices. Their discovery — made using a 2D electronic device — could represent the first steps towards making anyons the basis of future quantum computers.

“This does look like a very big deal,” says Steven Simon, a theoretical physicist at the University of Oxford, UK. The results, which have not yet been peer reviewed, were posted on the arXiv preprint repository last week1.

Known quasiparticles display a range of exotic behaviours. For example, magnetic monopole quasiparticles have only one magnetic pole — unlike all ordinary magnets, which always have a north and a south. Another example is Majorana quasiparticles, which are their own antiparticles.

Anyons are even more unique. All elementary particles fall into one of two possible types — fermions and bosons. Anyons are neither. The defining property of fermions (which include electrons) is Fermi statistics: when two identical fermions switch spatial positions, their quantum-mechanical wave — the wave function — is rotated by 180 degrees. When bosons exchange places, their wave doesn’t change. Switching two anyons should produce a rotation by some intermediate angle, an effect called fractional statistics that can cannot occur in three-dimensional space but only as collective states of electrons confined to move in two dimensions.

Fractional statistics

Fractional statistics is the defining property of anyons, and the latest work — led by Michael Manfra, an experimental physicist at Purdue University in West Lafayette, Indiana — is the first time it has been measured so conclusively.

The quasiparticles’ unusual behaviour when switching places means that if one moves in a full circle around the other — equivalent to the two particles switching positions twice — it will retain a memory of that motion in its quantum state. That memory is one of the tell-tale signs of fractional statistics that experimentalists have been looking for.

Manfra and his team manufactured a structure of thin layers of gallium arsenide and aluminium gallium arsenide. It confines electrons to move in two dimensions, while shielding them from stray electric charges in the rest of the device. They then cooled it to 10 thousandths of a degree above absolute zero and added a strong magnetic field, producing a state of matter called a ‘fractional quantum Hall’ (FQH) insulator that has the peculiarity that no electrical current can run in the interior of the two-dimensional device, but can run along the edge. FQH insulators can host quasiparticles that have an electric charge that is not a multiple of the electron charge, but one-third of one: these quasiparticles have long been suspected to be anyons.

To prove that they were indeed anyons, the team etched the device so that it could carry currents from one electrode to another along two possible edge paths. They tweaked the conditions by varying the magnetic field and adding an electric field. These tweaks were expected to create or destroy anyon states stuck in the interior, and also to produce anyons running between the electrodes. Because moving anyons had two possible paths, each producing a different twist in their quantum-mechanical waves, when the anyons reached the end point their quantum-mechanical waves produced an interference pattern called pyjama stripes.

This pattern shows how the relative amount of rotation between the two paths varies in response to changes in the voltage and the magnetic-field strength. But the interference also displayed jumps, which were the smoking gun2 for the appearance or disappearance of anyons in the bulk of the material.

“As far as I can tell, it is an extremely solid observation of anyons — directly observing their defining property: that they accumulate a fractional phase when one anyon travels around another,” Simon says.

It is not the first time that researchers have reported evidence of fractional statistics. Robert Willett, a physicist at Nokia Bell Labs in Murray Hill, New Jersey, says that his team saw “strong evidence” for fractional statistics in 20133.

And other teams have probed a different property that makes anyons an intermediate between fermions and bosons. Fermions obey the Pauli exclusion principle: no two fermions can ever occupy the same exact quantum state. But bosons have no such restrictions. Anyons are in the middle — they do bunch, but not as much as bosons do, as an experiment described in April in Science reported. “It is strikingly different from the fermionic behavior that we can also probe in the same set-up,” says Gwendal Feve, an experimentalist at the Sorbonne University in Paris who led that effort.

Quantum computing

But some theoretical physicists say that the evidence in these and other experiments, although striking, was not conclusive. “In many cases, there are several ways of explaining an experiment,” says Bernd Rosenow, a condensed-matter theorist at the University of Leipzig in Germany. But the evidence reported by Manfra’s team, if confirmed, is unequivocal, Rosenow says. “I’m not aware of an explanation of this experiment which is plausible and does not involve fractional statistics.”

The work potentially lays ground work for the application of anyons. Simon and others have invented some elaborate schemes to use anyons as the platform for quantum computers. Pairs of the quasiparticle could encode information in their memory of how they have circled around one another. And because the fractional statistics is ‘topological’ — it depends on the number of times an anyon went around another, not on slight changes to its path — it is unaffected by tiny perturbations. This robustness could make topological quantum computers easier to scale up than current quantum-computing technologies, which are error-prone. Microsoft (which employs Manfra as a consultant) has been alone in pursuing the topology path for quantum computing, while other large companies, including IBM, Intel, Google and Honeywell have invested in other approaches.

Topological quantum computing will require more sophisticated anyons than those Manfra and colleagues have demonstrated; his team is now redesigning their device to do just that. Still, anyon applications are a way off, researchers warn. “Even with this new result it is very hard to see [fractional quantum-Hall] anyons as a strong contender for quantum computing,” Simon says.

But the quasiparticles’ unique physics is worth exploring: “To me, as a condensed-matter theorist, they are at least as fascinating and exotic as the Higgs particle,” says Rosenow.

Majorana quasiparticles: https://www.nature.com/news/a-solid-case-for-majorana-fermions-1.10174

Nature doi: 10.1038/d41586-020-01988-0

References:

    1. Nakamura, J., Liang, S., Gardner, G. C. & Manfra, M. J. https://arxiv.org/abs/2006.14115 (2020).

    2. Bartolomei, H. et al. Science 368, 173–177 (2020).
       Google Scholar: http://scholar.google.com/scholar_lookup?&journal=Science&volume=368&pages=173-177&publication_year=2020&author=Bartolomei%2CH.

    3. Willett, R. L. et al. Phys. Rev. Lett. 111, 186401 (2013).
       Google Scholar: http://scholar.google.com/scholar_lookup?&journal=Phys.%20Rev.%20Lett.&volume=111&publication_year=2013&author=Willett%2CR.%20L.

    4. Rosenow, B. & Stern, A. Phys. Rev. Lett. 124, 106805 (2020).
       PubMed: http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&dopt=Abstract&list_uids=32216381

       Article: https://doi.org/10.1103%2FPhysRevLett.124.106805

       Google Scholar: http://scholar.google.com/scholar?q=10.1103%2FPhysRevLett.124.106805

Download references: https://www.nature.com/articles/d41586-020-01988-0-references.ris

Image (mentioned), Text, Credits: Nature/Davide Castelvecchi.

Greetings, Orbiter.ch

Long March-4B launches Gaofen Multi-Mode and Xibaipo 8102 satellites













XIBAIPO Middle School Students Satellite 8102 for Popular Science patch.

July 3, 2020

Long March-4B launches Gaofen Multi-Mode and Xibaipo 8102 satellites

A Long March-4B launch vehicle launched a new Gaofen “high-resolution multi-mode integrated imaging satellite” and the “Popular Science Satellite” 8102 from the Taiyuan Satellite Launch Center, Shanxi Province, northern China, on 03 July 2020, at 03:10 UTC (11:10 local time).

Long March-4B launches Gaofen Multi-Mode and Xibaipo 8102 satellites

According to official sources, the satellites entered their planned orbits. Gaofen Multi-Mode is an optical remote sensing satellite, mainly used for high-resolution image acquisition.

Gaofen Multi-Mode satellite

The Xibaipo “Popular Science Satellite” 8102 is mainly used for the popularization of aerospace science education.

China National Space Administration (CNSA): http://www.cnsa.gov.cn/english/index.html

China Aerospace Science and Technology Corporation (CASC): http://english.spacechina.com/n16421/index.html

Images, Video, Text, Credits: CASC/CNSA/China Central Television (CCTV)/SciNews/Orbiter.ch Aerospace/Roland Berga.

Greetings, Orbiter.ch

jeudi 2 juillet 2020

Astronauts Check Suits Following Spacewalk













ISS - Expedition 63 Mission patch.

July 2, 2020

Spacesuit checks were on the schedule today for the Expedition 63 crew following a spacewalk to replace aging batteries on the International Space Station. The orbital residents also juggled a variety of science activities.

NASA astronauts Chris Cassidy and Bob Behnken are back to work today after Wednesday’s spacewalk to swap batteries and route cables on the station’s Starboard-6 truss structure. The duo recharged batteries and refilled water tanks inside their U.S. spacesuits. Flight Engineer Doug Hurley also joined the pair in the afternoon for eye scans with an ultrasound device.


Image above: Astronaut Bob Behnken works during a spacewalk to swap an aging nickel-hydrogen battery for a new lithium-ion battery. Image Credit: NASA.

All three astronauts called down to Mission Control today and briefed specialists with the results of the mission’s second spacewalk. Station managers will assess the orbital lab’s upgraded power status before scheduling more battery swap spacewalks later this month.

Cassidy also configured cables on a specialized furnace before uploading new software to the high-temperature research device. Hurley worked with experiment hardware that seeks to better control the separation of blood cells and plasma to improve medical diagnostic devices.

International Space Station (ISS). Animation Credit: NASA

Cosmonauts Anatoly Ivanishin and Ivan Vagner partnered up Thursday morning for cardiac research. The duo is studying how the heart reacts to a unique suit that reverses the flow of blood towards the head caused by weightlessness. The pair then split up for life support maintenance and radiation checks.

Related article:

Cassidy and Behnken Wrap Up Battery Spacewalk
https://orbiterchspacenews.blogspot.com/2020/07/cassidy-and-behnken-wrap-up-battery.html

Related links:

Expedition 63: https://www.nasa.gov/mission_pages/station/expeditions/expedition63/index.html

Commercial Crew Program: https://www.nasa.gov/exploration/commercial/crew/index.html

Starboard-6 truss structure: https://www.nasa.gov/mission_pages/station/structure/elements/truss-structure

Specialized furnace: https://www.nasa.gov/mission_pages/station/research/experiments/explorer/Facility.html?#id=1536

Separation of blood cells and plasma: https://www.nasa.gov/mission_pages/station/research/experiments/explorer/Investigation.html?#id=7377

Cardiac research: https://www.energia.ru/en/iss/researches/human/10.html

Unique suit: https://blogs.nasa.gov/ISS_Science_Blog/2015/06/02/rubber-vacuum-pants-that-suck/

Space Station Research and Technology: https://www.nasa.gov/mission_pages/station/research/overview.html

International Space Station (ISS): https://www.nasa.gov/mission_pages/station/main/index.html

Image (mentioned), Animation (mentioned), Text, Credits: NASA/Mark Garcia.

Best Regards, Orbiter.ch

Space Station Science Highlights: Week of June 29, 2020













ISS - Expedition 63 Mission patch.

July 2, 2020

Scientific investigations conducted aboard the International Space Station during the week of June 29 included research on autonomous robot assistants, the properties of liquid metals, and the physics of neutron stars.

Now in its 20th year of continuous human presence, the space station provides a platform for long-duration research in microgravity and for learning to live and work in space. NASA’s Commercial Crew Program, once again launching astronauts on American rockets and spacecraft from American soil, increases the crew time available for science on the orbiting lab.

Here are details on some of the microgravity investigations currently taking place:

Astrobees buzzing along


Image above: NASA astronaut Chris Cassidy works with Honey, one of three Astrobee free-flying robots the crew is testing aboard the space station. Another Astrobee, Bumble, is visible docked to a charging station to Cassidy’s right. The autonomous robots could eventually perform routine tasks and free up astronaut time for more science. Image Credit: NASA.

Crew members initiated the first autonomous operations this week for Astrobee, free-flying robots designed to help scientists and engineers develop and test technologies that can assist astronauts with routine chores and give ground controllers additional eyes and ears on the space station. Crew members have been testing capabilities of the three cube-shaped devices – named Honey, Bumble, and Queen – such as computer vision, robotic manipulation, control algorithms, and human-robot interaction. Similar robots ultimately could perform crew monitoring, scientific sampling, logistics management, and other activities and allow astronauts to focus more on science and engineering duties. The Astrobees operate autonomously but can be controlled from the ground as well. After completion of commissioning activities, Astrobee replaces the SPHERES robots that have operated on the space station for more than a decade.

Molten metal in microgravity

Materials manufactured from liquid metal could revolutionize production of future spacecraft and other hardware. Round Robin - Thermophysical Property Measurement (Round Robin), an investigation from the Japan Aerospace Exploration Agency (JAXA), examines the properties of molten metals in microgravity to improve models of flow of liquids in manufacturing processes. Many of the materials investigated currently are used to manufacture a wide range of space hardware and others are new materials that NASA and commercial space companies plan to use to make devices for exploration and colonization missions. The project also could help companies make faster, better, and lower-cost consumer products on Earth.


Image above: The International Space Station's U.S. forward segment with the SpaceX Crew Dragon vehicle (right center) docked to the Harmony module's International Docking Adapter. Adjacent to the Crew Dragon is the H-II Transfer Vehicle-9 (HTV-9) from the Japan Aerospace Exploration Agency attached to the Harmony module's Earth-facing port. Image Credit: NASA.

The extraordinary physics of neutron stars

Thanks to increasing automation and careful planning, a number of investigations aboard the space station require little or no crew involvement. One such investigation operating during the week, Neutron star Interior Composition Explorer (NICER), studies the extraordinary physics of neutron stars. The glowing cinders left behind when massive stars explode as supernovas, these stars are the densest objects in the universe and contain exotic states of matter impossible to replicate in any lab. They get the name “pulsar” from their bright beams of light that sweep the sky as the stars spin, making them appear to pulse. NICER also contains software for the Station Explorer for X-ray Timing and Navigation Technology (SEXTANT) demonstration, which studies using pulsars as natural beacons for a future GPS-like system for spacecraft navigation.


Image above: The International Space Station's main solar arrays drape across the Earth above the Pacific Ocean west of Hawaii. Image Credit: NASA.

Other investigations on which the crew performed work:

- Capillary forces, the interaction of a liquid with the solid sides of a narrow tube that acts to draw the fluid up the tube, act even in the absence of gravity. Capillary Driven Microfluidics examines capillary flow in small devices to improve understanding of how it works in microgravity. Microfluidic devices could be used to develop more portable, robust, and affordable medical diagnostic tools to protect the health of astronauts on future long-term missions.
https://www.nasa.gov/mission_pages/station/research/experiments/explorer/Investigation.html?#id=7377

- An investigation from the Canadian Space Agency, Radi-N2 Neutron Field Study (Radi-N2), characterizes the neutron radiation environment aboard the space station using eight neutron “bubble detectors” that only measure neutrons and ignore other forms of radiation.
https://www.nasa.gov/mission_pages/station/research/experiments/explorer/Investigation.html?#id=874

- The Integrated Impact of Diet on Human Immune Response, the Gut Microbiota, and Nutritional Status During Adaptation to Spaceflight (Food Physiology) investigation documents the effects of dietary improvements on immune function and the gut microbiome and the ability of those improvements to support adaptation to spaceflight.
https://www.nasa.gov/mission_pages/station/research/experiments/explorer/Investigation.html?#id=7870

 A Power Spacewalk Outside the Space Station on This Week @NASA – June 26, 2020

Related links:

Expedition 63: https://www.nasa.gov/mission_pages/station/expeditions/expedition63/index.html

Commercial Crew Program: https://www.nasa.gov/exploration/commercial/crew/index.html

Astrobee: https://www.nasa.gov/mission_pages/station/research/experiments/explorer/Facility.html?#id=1891

SPHERES: https://www.nasa.gov/mission_pages/station/research/experiments/explorer/Facility.html?#id=1760

Round Robin: https://www.nasa.gov/mission_pages/station/research/experiments/explorer/Investigation.html?#id=8016

Crew involvement: https://www.nasa.gov/mission_pages/station/research/news/research-aboard-iss-continues-with-nasa-astronaut-chris-cassidy

NICER: https://www.nasa.gov/mission_pages/station/research/experiments/explorer/Investigation.html?#id=1705

Spacecraft navigation: https://www.nasa.gov/mission_pages/station/research/news/future-space-travelers-may-follow-cosmic-lighthouses-sextant-results

ISS National Lab: https://www.issnationallab.org/

Spot the Station: https://spotthestation.nasa.gov/

Space Station Research and Technology: https://www.nasa.gov/mission_pages/station/research/overview.html

International Space Station (ISS): https://www.nasa.gov/mission_pages/station/main/index.html

Images (mentioned), Video (NASA), Text, Credits: NASA/Michael Johnson/John Love, Lead Increment Scientist Expedition 63.

Greetings, Orbiter.ch

Hubble Spots Feathered Spiral













NASA - Hubble Space Telescope patch.

July 2, 2020


The spiral pattern shown by the galaxy in this image from the NASA/ESA Hubble Space Telescope is striking because of its delicate, feathery nature. These "flocculent" spiral arms indicate that the recent history of star formation of the galaxy, known as NGC 2775, has been relatively quiet. There is virtually no star formation in the central part of the galaxy, which is dominated by an unusually large and relatively empty galactic bulge, where all the gas was converted into stars long ago.

NGC 2275 is classified as a flocculent (or fluffy-looking) spiral galaxy, located 67 million light-years away in the constellation of Cancer.

Millions of bright, young, blue stars shine in the complex, feather-like spiral arms, interlaced with dark lanes of dust. Complexes of these hot, blue stars are thought to trigger star formation in nearby gas clouds. The overall feather-like spiral patterns of the arms are then formed by shearing of the gas clouds as the galaxy rotates. The spiral nature of flocculent galaxies stands in contrast to the grand-design spirals, which have prominent, well defined-spiral arms.

Hubble Space Telescope (HST)

For more information about Hubble, visit:

http://hubblesite.org/

http://www.nasa.gov/hubble

http://www.spacetelescope.org/

Text Credits: ESA (European Space Agency)/NASA/Rob Garner/Image, Animation Credits: ESA/Hubble & NASA, J. Lee and the PHANGS-HST Team; Acknowledgment: Judy Schmidt (Geckzilla).

Best regards, Orbiter.ch

"Clyde’s Spot" on Jupiter













NASA - JUNO Mission logo.

July 2, 2020


This image from NASA’s Juno spacecraft captures several storms in Jupiter’s southern hemisphere (Figure A). Some of these storms, including the Great Red Spot at upper left, have been churning in the planet’s atmosphere for many years, but when Juno obtained this view of Jupiter, the smaller, oval-shaped feature at the center of the image was brand new.

The new feature was discovered by amateur astronomer Clyde Foster of Centurion, South Africa. Early on the morning of May 31, 2020, while imaging Jupiter with his telescope, Foster noticed a new spot, which appeared bright as seen through a filter sensitive to wavelengths of light where methane gas in Jupiter's atmosphere has strong absorption. The spot was not visible in images captured just hours earlier by astronomers in Australia.

Juno spacecraft orbiting Jupiter. Animation Credit: NASA

On June 2, 2020, just two days after Clyde Foster’s observations, Juno performed its 27th close flyby of Jupiter. The spacecraft can only image a relatively thin slice of Jupiter's cloud tops during each pass. Although Juno would not be travelling directly over the outbreak, the track was close enough that the mission team determined the spacecraft would obtain a detailed view of the new feature, which has been informally dubbed “Clyde’s Spot.”

The feature is a plume of cloud material erupting above the upper cloud layers of the Jovian atmosphere. These powerful convective "outbreaks" occasionally erupt in this latitude band, known as the South Temperate Belt (JunoCam observed another outbreak at this latitude back on Feb. 7, 2018).

Figure B

Figure B shows Jupiter as captured by Foster’s telescope, and the Juno spacecraft’s approximate trajectory as it zoomed close by the planet, traveling from north to south.

Another citizen scientist, Kevin M. Gill, created Figure A using data from Juno’s JunoCam instrument. This view is a map projection that combines five JunoCam images taken on June 2, 2020, between 3:56 a.m. PDT (6:56 a.m. EDT) and 4:25 a.m. PDT (7:25 a.m. EDT). At the time the images were taken, Juno was between about 28,000 miles (45,000 kilometers) and 59,000 miles (95,000 kilometers) from the planet’s cloud tops at latitudes of between about 48 degrees and 67 degrees south.

JunoCam's raw images are available for the public to peruse and process into image products at https://missionjuno.swri.edu/junocam/processing.   

More information about Juno is at https://www.nasa.gov/juno and https://missionjuno.swri.edu.

Images, Animation, Text, Credits: Image data: NASA/JPL-Caltech/SwRI/MSSS/Clyde Foster (Figure B)/Image processing by Kevin M. Gill © CC BY/Naomi Hartono.

Greetings, Orbiter.ch

Space Station science and spring-cleaning special













ISS - International Space Station logo.

July 2, 2020

The arrival of NASA astronauts Bob Behnken and Doug Hurley in the first crewed SpaceX Dragon on 31 May brought the Space Station crew to five and heralded the start of a new month of science 400 km above our heads.

Proximity and plasma

The current situation with COVID-19 on Earth meant a few necessary adaptations for support teams on the ground – including a new way of working together for principal investigators (PI) of the long-standing Russian-European investigation Plasma Kristall 4 (PK-4).

PK4 ready to return

Rather than travelling to the CADMOS centre in Toulouse, France, to support the experiment together on console, one researcher worked from Russian mission control centre TsUP while the other was stationed at the Columbus Control Centre (Col-CC) in Oberpfaffenhofen, Germany to complete the 10th campaign of PK-4 on the Space Station.

PK-4’s focus is low temperature gaseous mixtures known as ‘complex plasmas’ made up of ions, electrons, inert gas and micro-particles. Due to the strong influence of gravity on the micro-particles, most experiments on complex plasmas are strongly distorted or even impossible on Earth. 

Plasma for the PK-4 experiment is created with neon or argon gas in tubes that give particles an electrical charge. The experiment allows researchers across the world to better understand how an object melts, how waves spread in fluids and how currents change at the atomic level.

In fact, a team of scientists has already made use of the know-how gained from developing the experiment to build plasma devices that disinfect wounds at room temperature. This revolution in healthcare has many practical applications, from food hygiene to treatment of skin diseases, water purification and even neutralising bad odours.

Space renovations

Europe’s Columbus laboratory got a spruce up this month as Bob and Doug moved the European Drawer Rack-2 (EDR-2) into its new position.

Rather than replacing the existing European Drawer Rack, EDR-2 is designed to run in parallel, providing even greater opportunities for science in space. 

The addition is part of a comprehensive upgrade of Columbus to offer faster, easier and more flexible access for researchers on Earth. It does so by offering more room to support and operate experiments by supplying power, data communication, cooling and nitrogen, and venting waste gasses.

Installing European Drawer Rack-2

The first three experiments planned for installation in EDR-2 include a metal 3D printer, an instrument investigating granular materials and a facility looking into heat transfer.

Bob and Doug manoeuvred the large fridge-sized rack into Columbus – a feat that would be much more difficult on Earth – and shifted the European Transport Carrier (ETC) out. Having served its time as a workbench and stowage facility, ETC was transferred to the Japanese HTV 9 spacecraft and will now be trashed.

Steady science and spacewalks

Among other experiments operational in June were some familiar favourites. The Atmosphere-Space Interactions Monitor (ASIM) continued to observe a wide variety of phenomena in Earth’s upper atmosphere.

Artist's impression of a terrestrial gamma-ray flash

Data was also downlinked from the Dosis-3D radiation monitoring experiment, and the Foam Coarsening experiment continued to study the behaviour of foams to help in the construction of light-weight and sturdy aerospace structures and new shielding systems for diagnostic radiology equipment in hospitals.

Not content to simply work inside the Space Station, Chris Cassidy and Bob Behnken took a walk outside, marking the start of a fresh series of spacewalks. The spacewalking duo exited the Quest airlock on Friday 26 June in the first of two scheduled spacewalks to replace batteries on one of two power channels on the far starboard truss (S6 Truss). The second spacewalk was completed Wednesday 1 July.

Related links:

Plasma devices: http://youbenefit.spaceflight.esa.int/plasma-for-a-safer-world/

European Transport Carrier (ETC): https://www.esa.int/Science_Exploration/Human_and_Robotic_Exploration/Columbus/European_Transport_Carrier

International Space Station (ISS): https://www.esa.int/Science_Exploration/Human_and_Robotic_Exploration/International_Space_Station

Image, Video, Animation, Text, Credits: ESA/NASA.

Greetings, Orbiter.ch

mercredi 1 juillet 2020

LHCb discovers a new type of tetraquark at CERN













CERN - European Organization for Nuclear Research logo.

July 1, 2020

The LHCb collaboration has observed an exotic particle made up of four charm quarks for the first time.


Image above: Illustration of a tetraquark composed of two charm quarks and two charm antiquarks, detected for the first time by the LHCb collaboration at CERN. (Image: CERN).

The LHCb collaboration has observed a type of four-quark particle never seen before. The discovery, presented at a recent seminar at CERN and described in a paper posted today on the arXiv preprint server, is likely to be the first of a previously undiscovered class of particles.

The finding will help physicists better understand the complex ways in which quarks bind themselves together into composite particles such as the ubiquitous protons and neutrons that are found inside atomic nuclei.

Quarks typically combine together in groups of twos and threes to form particles called hadrons. For decades, however, theorists have predicted the existence of four-quark and five-quark hadrons, which are sometimes described as tetraquarks and pentaquarks, and in recent years experiments including the LHCb have confirmed the existence of several of these exotic hadrons. These particles made of unusual combinations of quarks are an ideal “laboratory” for studying one of the four known fundamental forces of nature, the strong interaction that binds protons, neutrons and the atomic nuclei that make up matter. Detailed knowledge of the strong interaction is also essential for determining whether new, unexpected processes are a sign of new physics or just standard physics.

“Particles made up of four quarks are already exotic, and the one we have just discovered is the first to be made up of four heavy quarks of the same type, specifically two charm quarks and two charm antiquarks,” says the outgoing spokesperson of the LHCb collaboration, Giovanni Passaleva. “Up until now, the LHCb and other experiments had only observed tetraquarks with two heavy quarks at most and none with more than two quarks of the same type.”

“These exotic heavy particles provide extreme and yet theoretically fairly simple cases with which to test models that can then be used to explain the nature of ordinary matter particles, like protons or neutrons. It is therefore very exciting to see them appear in collisions at the LHC for the first time,” explains the incoming LHCb spokesperson, Chris Parkes.

The LHCb team found the new tetraquark using the particle-hunting technique of looking for an excess of collision events, known as a “bump”, over a smooth background of events. Sifting through the full LHCb datasets from the first and second runs of the Large Hadron Collider, which took place from 2009 to 2013 and from 2015 to 2018 respectively, the researchers detected a bump in the mass distribution of a pair of J/ψ particles, which consist of a charm quark and a charm antiquark. The bump has a statistical significance of more than five standard deviations, the usual threshold for claiming the discovery of a new particle, and it corresponds to a mass at which particles composed of four charm quarks are predicted to exist.

Large Hadron Collider (LHC). Animation Credit: NASA

As with previous tetraquark discoveries, it is not completely clear whether the new particle is a “true tetraquark”, that is, a system of four quarks tightly bound together, or a pair of two-quark particles weakly bound in a molecule-like structure. Either way, the new tetraquark will help theorists test models of quantum chromodynamics, the theory of the strong interaction.

Read more on the LHCb website:
https://lhcb-public.web.cern.ch/Welcome.html#Tcccc

Note:

CERN, the European Organization for Nuclear Research, is one of the world’s largest and most respected centres for scientific research. Its business is fundamental physics, finding out what the Universe is made of and how it works. At CERN, the world’s largest and most complex scientific instruments are used to study the basic constituents of matter — the fundamental particles. By studying what happens when these particles collide, physicists learn about the laws of Nature.

The instruments used at CERN are particle accelerators and detectors. Accelerators boost beams of particles to high energies before they are made to collide with each other or with stationary targets. Detectors observe and record the results of these collisions.

Founded in 1954, the CERN Laboratory sits astride the Franco–Swiss border near Geneva. It was one of Europe’s first joint ventures and now has 23 Member States.

Related links:

CERN paper: https://arxiv.org/abs/2006.16957

Large Hadron Collider (LHC): https://home.cern/science/accelerators/large-hadron-collider

LHCb experiment: https://lhcb-public.web.cern.ch/lhcb-public/Welcome.html

For more information about European Organization for Nuclear Research (CERN), Visit: https://home.cern/

Image (mentioned), Animation (mentioned), Text, Credits: European Organization for Nuclear Research (CERN).

Best regards, Orbiter.ch

Cassidy and Behnken Wrap Up Battery Spacewalk















ISS - Expedition 63 Mission patch / EVA - Extra Vehicular Activities patch.

July 1, 2020

NASA astronauts Chris Cassidy and Robert Behnken concluded their spacewalk at 12:14 p.m. EDT. During the six hour and one-minute spacewalk, the two NASA astronauts completed half the work to upgrade the batteries that provide power for one channel on one pair of the station’s solar arrays. The new batteries provide an improved and more efficient power capacity for operations.

They successfully moved and connected one new, powerful lithium-ion battery and its adapter place to complete the circuit to the new battery and relocated one aging nickel-hydrogen battery to an external platform for future disposal.


Image above: NASA astronaut Bob Behnken is pictured tethered to the space station’s truss structure during a spacewalk to swap batteries and route cables. Image Credit: NASA TV.

They also loosened the bolts on nickel-hydrogen batteries that will be replaced to complete the power capability upgrade on the far starboard truss and complete the station’s battery replacement work that began in January 2017 with the first series of power upgrade spacewalks. Behnken and Cassidy will complete the work during the final two spacewalks later this month.

Cassidy and Behnken also will route power and ethernet cables in preparation for the installation of a new external wireless communications system with an enhanced HD camera and to increase helmet camera coverage for future spacewalks. To support future power system upgrades, they also will remove a device called an “H-Fixture” that was installed before the solar arrays were launched to the space station.


Image above: On June 26, 2020, NASA astronauts Bob Behnken and Chris Cassidy conducted the first of two spacewalks to swap batteries and upgrade power systems on the International Space Station's Starboard-6 truss structure. Behnken is pictured here during the six-hour and seven-minute excursion. The two astronauts conducted a second spacewalk on July 1 to complete the upgrades. Image Credit: NASA.

This was the eighth spacewalk for both each astronaut. Cassidy now has spent a total of 43 hours and 22 minutes spacewalking. Behnken has now spent a total of 49 hours and 41 minutes spacewalking.

Space station crew members have conducted 229 spacewalks in support of assembly and maintenance of the orbiting laboratory. Spacewalkers have now spent a total of 60 days and 34 minutes working outside the station.


Image above: Today spacewalk of NASA Astronauts Chris Cassidy and Bob Behnken to replace batteries to upgrade the power supply capability of the Space Station on the truss structure. Image Credits: NASA TV/ISS HD Live Now/Orbiter.ch Aerospace/Roland Berga.

At 4 p.m. today, NASA astronaut Kate Rubins will discuss her upcoming second mission to the International Space Station, along with cosmonauts Sergey Ryzhikov and Sergey Kud-Sverchkov of the Russian space agency Roscosmos, during a news conference from NASA’s Johnson Space Center in Houston that will be broadcast live on NASA Television and on the agency’s website.

Related article:

Cassidy and Behnken Conclude Spacewalk to Replace Batteries
https://orbiterchspacenews.blogspot.com/2020/06/cassidy-and-behnken-conclude-spacewalk.html

Related links:

NASA Television: https://www.nasa.gov/live

Expedition 63: https://www.nasa.gov/mission_pages/station/expeditions/expedition63/index.html

Commercial Crew Program: https://www.nasa.gov/exploration/commercial/crew/index.html

Space Station Research and Technology: https://www.nasa.gov/mission_pages/station/research/overview.html

International Space Station (ISS): https://www.nasa.gov/mission_pages/station/main/index.html

Images, Text, Credits: NASA/Mark Garcia/Orbiter.ch Aerospace/Roland Berga.

Best regards, Orbiter.ch

Radar Points to Moon Being More Metallic Than Researchers Thought













NASA - Lunar Reconnaissance Orbiter (LRO) patch.

July 1, 2020

What started out as a hunt for ice lurking in polar lunar craters turned into an unexpected finding that could help clear some muddy history about the Moon’s formation.

Team members of the Miniature Radio Frequency (Mini-RF) instrument on NASA’s Lunar Reconnaissance Orbiter (LRO) spacecraft found new evidence that the Moon’s subsurface might be richer in metals, like iron and titanium, than researchers thought. That finding, published July 1 in Earth and Planetary Science Letters, could aid in drawing a clearer connection between Earth and the Moon.

“The LRO mission and its radar instrument continue to surprise us with new insights about the origins and complexity of our nearest neighbor,” said Wes Patterson, Mini-RF principal investigator from the Johns Hopkins Applied Physics Laboratory (APL) in Laurel, Maryland, and a study coauthor.


Image above: This image based on data from NASA’s Lunar Reconnaissance Orbiter spacecraft shows the face of the Moon we see from Earth. The more we learn about our nearest neighbor, the more we begin to understand the Moon as a dynamic place with useful resources that could one day even support human presence. Image Credits: NASA / GSFC / Arizona State University.

Substantial evidence points to the Moon as the product of a collision between a Mars-sized protoplanet and young Earth, forming from the gravitational collapse of the remaining cloud of debris. Consequently, the Moon’s bulk chemical composition closely resembles that of Earth.

Look in detail at the Moon’s chemical composition, however, and that story turns murky. For example, in the bright plains of the Moon’s surface, called the lunar highlands, rocks contain smaller amounts of metal-bearing minerals relative to Earth. That finding might be explained if Earth had fully differentiated into a core, mantle and crust before the impact, leaving the Moon largely metal-poor. But turn to the Moon’s maria — the large, darker plains — and the metal abundance becomes richer than that of many rocks on Earth.

This discrepancy has puzzled scientists, leading to numerous questions and hypotheses regarding how much the impacting protoplanet may have contributed to the differences. The Mini-RF team found a curious pattern that could lead to an answer.

Using Mini-RF, the researchers sought to measure an electrical property within lunar soil piled on crater floors in the Moon’s northern hemisphere. This electrical property is known as the dielectric constant, a number that compares the relative abilities of a material and the vacuum of space to transmit electric fields, and could help locate ice lurking in the crater shadows. The team, however, noticed this property increasing with crater size.

For craters approximately 1 to 3 miles (2 to 5 kilometers) wide, the dielectric constant of the material steadily increased as the craters grew larger, but for craters 3 to 12 miles (5 to 20 kilometers) wide, the property remained constant.

“It was a surprising relationship that we had no reason to believe would exist,” said Essam Heggy, coinvestigator of the Mini-RF experiments from the University of Southern California in Los Angeles and lead author of the published paper.

Discovery of this pattern opened a door to a new possibility. Because meteors that form larger craters also dig deeper into the Moon’s subsurface, the team reasoned that the increasing dielectric constant of the dust in larger craters could be the result of meteors excavating iron and titanium oxides that lie below the surface. Dielectric properties are directly linked to the concentration of these metal minerals.

If their hypothesis were true, it would mean only the first few hundred meters of the Moon’s surface is scant in iron and titanium oxides, but below the surface, there’s a steady increase to a rich and unexpected bonanza.

Lunar Reconnaissance Orbiter (LRO). Animation Credit: NASA

Comparing crater floor radar images from Mini-RF with metal oxide maps from the LRO Wide-Angle Camera, Japan’s Kaguya mission and NASA’s Lunar Prospector spacecraft, the team found exactly what it had suspected. The larger craters, with their increased dielectric material, were also richer in metals, suggesting that more iron and titanium oxides had been excavated from the depths of 0.3 to 1 mile (0.5 to 2 kilometers) than from the upper 0.1 to 0.3 miles (0.2 to 0.5 kilometers) of the lunar subsurface.

“This exciting result from Mini-RF shows that even after 11 years in operation at the Moon, we are still making new discoveries about the ancient history of our nearest neighbor,” said Noah Petro, the LRO project scientist at NASA’s Goddard Space Flight Center in Greenbelt, Maryland. “The MINI-RF data is incredibly valuable for telling us about the properties of the lunar surface, but we use that data to infer what was happening over 4.5 billion years ago!”

These results follow recent evidence from NASA’s Gravity Recovery and Interior Laboratory (GRAIL) mission that suggests a significant mass of dense material exists just a few tens to hundreds of kilometers beneath the Moon’s enormous South Pole-Aitken basin, indicating that dense materials aren’t uniformly distributed in the Moon’s subsurface.

The team emphasizes that the new study can’t directly answer the outstanding questions about the Moon’s formation, but it does reduce the uncertainty in the distribution of iron and titanium oxides in the lunar subsurface and provide critical evidence needed to better understand the Moon’s formation and its connection to Earth.

“It really raises the question of what this means for our previous formation hypotheses,” Heggy said.

Anxious to uncover more, the researchers have already started examining crater floors in the Moon’s southern hemisphere to see if the same trends exist there.

LRO is managed by NASA’s Goddard Space Flight Center in Greenbelt, Maryland for the Science Mission Directorate at NASA Headquarters in Washington. Mini-RF was designed, built and tested by a team led by APL, Naval Air Warfare Center, Sandia National Laboratories, Raytheon and Northrop Grumman.

For more information on LRO, visit: https://www.nasa.gov/lro

Image (mentioned), Animation (mentioned), Text, Credits: NASA/Karl Hille/GSFC/Nancy Neal Jones/JHAPL/Jeremy Rehm.

Greetings, Orbiter.ch

Gaia revolutionises asteroid tracking













ESA - Gaia Mission patch.

July 1,2020

ESA’s Gaia space observatory is an ambitious mission to construct a three-dimensional map of our galaxy by making high-precision measurements of over one billion stars. However, on its journey to map distant suns, Gaia is revolutionising a field much closer to home. By accurately mapping the stars, it is helping researchers track down lost asteroids.

Gaia mapping the stars of the Milky Way

Using stars to spot asteroids

Gaia charts the galaxy by repeatedly scanning the entire sky. Over the course of its planned mission, it observed each of its more than one billion target stars around 70 times to study how their position and brightness change over time.

The stars are so far from Earth that their movements between images are very small, hence why Gaia has to measure their positions so accurately to even notice a difference. However, sometimes Gaia spots faint light sources that move considerably from one image of a certain region of the sky to the next, or are even only spotted in a single image before disappearing.

Asteroid Gaia-606 on 26 October 2016

To move across Gaia’s field of view so quickly, these objects must be located much closer to Earth.

By checking the positions of these objects against the catalogues of known Solar System bodies, many of these objects turn out to be known asteroids. Some, however, are identified as potentially new detections and are then followed up by the astronomy community through the Gaia Follow-Up Network for Solar System Objects. Through this process, Gaia has successfully discovered new asteroids.

Lost and found

These direct asteroid observations are important for solar system scientists. However, Gaia’s highly accurate measurements of the positions of stars provide an even more impactful, but indirect, benefit for asteroid tracking.

“When we observe an asteroid, we look at its motion relative to the background stars to determine its trajectory and predict where it will be in the future,” says Marco Micheli from ESA’s Near-Earth Object Coordination Centre. “This means that the more accurately we know the positions of the stars, the more reliably we can determine the orbit of an asteroid passing in front of them.”

Lutetia at closest approach

In collaboration with the European Southern Observatory (ESO), Marco’s team took part in an observation campaign targeting 2012 TC4, a small asteroid that was due to pass by the Earth. Unfortunately, since the asteroid was first spotted in 2012, it had become fainter and fainter as it receded form Earth, eventually becoming unobservable. Where it would appear in the sky at the time of the upcoming campaign was not well known.

“The possible region of the sky where the asteroid might appear was larger than the area that the telescope could observe at one time,” says Marco. “So we had to find a way to improve our prediction of where the asteroid would be.”

“I looked back at the initial observations from 2012. Gaia had since made more accurate measurements of the positions of some of the stars in the background of the images, and I used these to update our understanding of the asteroid’s trajectory and predict where it would appear.”

“We pointed the telescope towards the predicted area of the sky using the data from Gaia and we found the asteroid on our first attempt.”

“Our next goal was to accurately measure the asteroid’s position, but we had very few stars in our new image to use as a reference. There were 17 stars listed in an older catalogue and only four stars measured by Gaia. I made calculations using both sets of data.”

“Later in the year, when the asteroid had been observed multiple times by other teams and its trajectory was better known, it became clear that the measurements I made using just four Gaia stars had been much more accurate than the ones using the 17 stars. This was really amazing.”

Hear Marco describe his work spotting risky asteroids - "the only natural disaster we can do something about" - in the latest ESA podcast!

https://soundcloud.com/esa

Keeping Earth safe
 
Gaia’s first asteroid survey

This same technique is being applied to asteroids that were never lost, allowing researchers to use data from Gaia to determine their trajectories and physical properties more accurately than ever before.

This is helping them update asteroid population models and deepen our understanding of how asteroid orbits develop, for example, by measuring subtle dynamical effects that play a key role in pushing small asteroids into orbits that could see them collide with Earth.

Dancing with daylight

In order to make such accurate measurements of the positions of other stars, Gaia has a complicated relationship with our own.

Gaia orbits around the second Lagrange point, L2, of the Sun-Earth system. This location keeps the Sun, Earth and Moon all behind Gaia, allowing it to observe a large portion of the sky without their interference. It is also in an even thermal radiation environment and experiences a stable temperature.

However, Gaia must not fall entirely into Earth’s shadow, as the spacecraft still depends on solar power. As the orbit around the L2 point is unstable, small disturbances can build up and see the spacecraft heading for an eclipse.

Avoiding Earth's shadow

Gaia’s flight control team at ESA’s ESOC mission control centre in Darmstadt are responsible for making corrections to the spacecraft’s trajectory to keep it in the correct orbit and out of Earth’s shadow. They ensure that Gaia remains one of the most stable and accurate spacecraft ever. On 16 July 2019, the team successfully performed a crucial eclipse avoidance manoeuvre, moving Gaia into the extended phase of its mission and allowing it to keep scanning the sky for several more years.

Related links:

ESA’s Near-Earth Object Coordination Centre: http://neo.ssa.esa.int/

ESA’s Gaia space observatory: https://www.esa.int/Science_Exploration/Space_Science/Gaia_overview

Images, Animation, Video, Text, Credits: ESA/ATG medialab; background: ESO/S. Brunier/Observatoire de Haute-Provence & IMCCE/ESA 2010 MPS for OSIRIS Team MPS/UPD/LAM/IAA/RSSD/INTA/UPM/DASP/IDA.

Best regards, Orbiter.ch

mardi 30 juin 2020

SpaceX - Falcon 9 launches GPS III SV03













SpaceX / US Air Force - Global Positioning System III (GPS) patch.

June 30, 2020

Falcon 9 launches GPS III SV03

A SpaceX Falcon 9 rocket launched the GPS III Space Vehicle 03 mission (GPS III SV03) from Space Launch Complex 40 (SLC-40) at Cape Canaveral Air Force Station, Florida, on 30 June 2020, at 20:10 UTC (16:10 EDT).

Falcon 9 launches GPS III SV03 & Falcon 9 first stage landing

GPS III SV03, named Columbus, is the United States Space Force’s third Global Positioning System III space vehicle (SV). Following stage separation, Falcon 9’s first stage (Block B1060) landed on the “Just Read the Instructions” drone-ship, stationed in the Atlantic Ocean.

Global Positioning System III space vehicle (SV)

A SpaceX Falcon 9 rocket will launch the U.S. Air Force’s third third-generation navigation satellite for the Global Positioning System. The satellite is built by Lockheed Martin. The Air Force previously planned to launch the second GPS 3-series satellite on this mission. Delayed from October, December, January and March.

SpaceX: https://www.spacex.com/

Images, Video, Text, Credits: SpaceX/Lockheed Martin/SciNews/Orbiter.ch Aerospace/Roland Berga.

Greetings, Orbiter.ch

NASA TV Goes Live Wednesday to Broadcast Spacewalk













ISS - Expedition 63 Mission patch.

June 30, 2020

NASA astronauts Chris Cassidy and Robert Behnken are scheduled to depart the International Space Station’s Quest airlock Wednesday for a spacewalk to complete battery replacement activities to upgrade one of two power channels on the station’s far starboard truss (S6 Truss). The upgrade includes removing six aging nickel-hydrogen batteries and replacing them with three new lithium-ion batteries and the adapter plates that complete the power circuit to the new batteries.

The duo will set their spacesuits to battery power about 7:35 a.m. EDT Wednesday, signifying the start of their spacewalk, which will last between six and seven hours. NASA will begin its live coverage on NASA Television and the agency’s website at 6 a.m.

NASA TV: https://www.nasa.gov/multimedia/nasatv/index.html


Image above: NASA astronaut Bob Behnken is pictured during a spacewalk to swap station batteries on June 26. Image Credit: NASA TV.

In a prior spacewalk June 26, Cassidy and Behnken began the work to complete the upgrade to this initial power channel, additionally completing some of the tasks originally scheduled for today. The remaining tasks for today are to install one more lithium-ion battery and one more adapter plate and remove the sixth nickel-hydrogen battery that will no longer be used. NASA animation depicts (video below) the originally scheduled spacewalk activities. The new lithium-ion batteries  arrived on a Japanese cargo ship last month.

NASA animation depicts the originally scheduled spacewalk activities

New tasks added for tomorrow’s spacewalk include loosening the bolts on the nickel-hydrogen batteries that will be replaced during two future spacewalks to complete the power capability upgrade on the far starboard truss and complete the station’s battery replacement work that began in January 2017 with the first series of power upgrade spacewalks.

Cassidy and Behnken also will route power and ethernet cables in preparation for the installation of a new external wireless communications system with an enhanced HD camera and to increase helmet camera coverage for future spacewalks. To support future power system upgrades, they also will remove a device called an “H-Fixture” that was installed before the solar arrays were launched to the space station.

International Space Station (ISS). Animation Credit: NASA

This will be the 229th spacewalk in support of space station assembly and maintenance. Cassidy again will be extravehicular crew member 1, wearing the spacesuit with red stripes, while Behnken will be extravehicular crew member 2, wearing the spacesuit with no stripes. It will be the eighth spacewalk for each astronaut.

Related links:

Expedition 63: https://www.nasa.gov/mission_pages/station/expeditions/expedition63/index.html

Commercial Crew Program: https://www.nasa.gov/exploration/commercial/crew/index.html

Starboard-6 truss structure: https://www.nasa.gov/mission_pages/station/structure/elements/truss-structure

Space Station Research and Technology: https://www.nasa.gov/mission_pages/station/research/overview.html

International Space Station (ISS): https://www.nasa.gov/mission_pages/station/main/index.html

Image (mentioned), Animation (mentioned), Video, Text, Credits: NASA/Mark Garcia.

Best regards, Orbiter.ch

NASA’s TESS Delivers New Insights Into an Ultrahot World













NASA - TESS Mission logo.

June 30, 2020

Measurements from NASA’s Transiting Exoplanet Survey Satellite (TESS) have enabled astronomers to greatly improve their understanding of the bizarre environment of KELT-9 b, one of the hottest planets known.

“The weirdness factor is high with KELT-9 b,” said John Ahlers, an astronomer at Universities Space Research Association in Columbia, Maryland, and NASA’s Goddard Space Flight Center in Greenbelt, Maryland. “It’s a giant planet in a very close, nearly polar orbit around a rapidly rotating star, and these features complicate our ability to understand the star and its effects on the planet.”

NASA’s TESS Delivers New Insights Into an Ultrahot World

Video above: Explore KELT-9 b, one of the hottest planets known. Observations from NASA's Transiting Exoplanet Survey Satellite (TESS) have revealed new details about the planet’s environment. The planet follows a close, polar orbit around a squashed star with different surface temperatures, factors that make peculiar seasons for KELT-9 b. Image Credits: NASA's Goddard Space Flight Center.

The new findings appear in a paper led by Ahlers published on June 5 in The Astronomical Journal: https://iopscience.iop.org/article/10.3847/1538-3881/ab8fa3

Located about 670 light-years away in the constellation Cygnus, KELT-9 b was discovered in 2017 because the planet passed in front of its star for a part of each orbit, an event called a transit. Transits regularly dim the star’s light by a small but detectable amount. The transits of KELT-9 b were first observed by the KELT transit survey, a project that collected observations from two robotic telescopes located in Arizona and South Africa.

Between July 18 and Sept. 11, 2019, as part of the mission’s yearlong campaign to observe the northern sky, TESS observed 27 transits of KELT-9 b, taking measurements every two minutes. These observations allowed the team to model the system’s unusual star and its impact on the planet.

KELT-9 b is a gas giant world about 1.8 times bigger than Jupiter, with 2.9 times its mass. Tidal forces have locked its rotation so the same side always faces its star. The planet swings around its star in just 36 hours on an orbit that carries it almost directly above both of the star’s poles.

KELT-9 b receives 44,000 times more energy from its star than Earth does from the Sun. This makes the planet’s dayside temperature around 7,800 degrees Fahrenheit (4,300 C), hotter than the surfaces of some stars. This intense heating also causes the planet’s atmosphere to stream away into space.


Image above: This illustration shows how planet KELT-9 b sees its host star. Over the course of a single orbit, the planet twice experiences cycles of heating and cooling caused by the star’s unusual pattern of surface temperatures. Between the star’s hot poles and cool equator, temperatures vary by about 1,500 F (800 C). This produces a “summer” when the planet faces a pole and a “winter” when it faces the cooler midsection. So every 36 hours, KELT-9 b experiences two summers and two winters. Image Credits: NASA's Goddard Space Flight Center/Chris Smith (USRA).

Its host star is an oddity, too. It’s about twice the size of the Sun and averages about 56 percent hotter. But it spins 38 times faster than the Sun, completing a full rotation in just 16 hours. Its rapid spin distorts the star’s shape, flattening it at the poles and widening its midsection. This causes the star’s poles to heat up and brighten while its equatorial region cools and dims — a phenomenon called gravity darkening. The result is a temperature difference across the star’s surface of almost 1,500 F (800 C).

With each orbit, KELT-9 b twice experiences the full range of stellar temperatures, producing what amounts to a peculiar seasonal sequence. The planet experiences “summer” when it swings over each hot pole and “winter” when it passes over the star’s cooler midsection. So KELT-9 b experiences two summers and two winters every year, with each season about nine hours.

“It’s really intriguing to think about how the star’s temperature gradient impacts the planet,” said Goddard’s Knicole Colón, a co-author of the paper. “The varying levels of energy received from its star likely produce an extremely dynamic atmosphere.”

KELT-9 b's polar orbit around its flattened star produces distinctly lopsided transits. The planet begins its transit near the star's bright poles and then blocks less and less light as it travels over the star's dimmer equator. This asymmetry provides clues to the temperature and brightness changes across the star’s surface, and they permitted the team to reconstruct the star’s out-of-round shape, how it’s oriented in space, its range of surface temperatures, and other factors impacting the planet.

Transiting Exoplanet Survey Satellite (TESS. Animation Credit: NASA

“Of the planetary systems that we've studied via gravity darkening, the effects on KELT-9 b are by far the most spectacular,” said Jason Barnes, a professor of physics at the University of Idaho and a co-author of the paper. “This work goes a long way toward unifying gravity darkening with other techniques that measure planetary alignment, which in the end we hope will tease out secrets about the formation and evolutionary history of planets around high-mass stars.”

TESS is a NASA Astrophysics Explorer mission led and operated by MIT in Cambridge, Massachusetts, and managed by NASA's Goddard Space Flight Center. Additional partners include Northrop Grumman, based in Falls Church, Virginia; NASA’s Ames Research Center in California’s Silicon Valley; the Harvard-Smithsonian Center for Astrophysics in Cambridge, Massachusetts; MIT’s Lincoln Laboratory; and the Space Telescope Science Institute in Baltimore. More than a dozen universities, research institutes and observatories worldwide are participants in the mission.

Related link:

KELT transit survey: https://keltsurvey.org/

TESS (Transiting Exoplanet Survey Satellite): http://www.nasa.gov/tess

Exoplanets: https://www.nasa.gov/content/the-search-for-life

Image (mentioned), Animation (mentioned), Video (mentioned), Text, Credits: NASA/Francis Reddy/GSFC/Claire Andreoli/Francis Reddy.

Greetings, Orbiter.ch