Closest Temperate World Orbiting Quiet Star Discovered

ESO - European Southern Observatory logo.

15 November 2017

ESO’s HARPS instrument finds Earth-mass exoplanet around Ross 128

Artist’s impression of the planet Ross 128 b

A temperate Earth-sized planet has been discovered only 11 light-years from the Solar System by a team using ESO’s unique planet-hunting HARPS instrument. The new world has the designation Ross 128 b and is now the second-closest temperate planet to be detected after Proxima b. It is also the closest planet to be discovered orbiting an inactive red dwarf star, which may increase the likelihood that this planet could potentially sustain life. Ross 128 b will be a prime target for ESO’s Extremely Large Telescope, which will be able to search for biomarkers in the planet's atmosphere.

A team working with ESO’s High Accuracy Radial velocity Planet Searcher (HARPS) at the La Silla Observatory in Chile has found that the red dwarf star Ross 128 is orbited by a low-mass exoplanet every 9.9 days. This Earth-sized world is expected to be temperate, with a surface temperature that may also be close to that of the Earth. Ross 128 is the “quietest” nearby star to host such a temperate exoplanet.

 The sky around the red dwarf star Ross 128

“This discovery is based on more than a decade of HARPS intensive monitoring together with state-of-the-art data reduction and analysis techniques. Only HARPS has demonstrated such a precision and it remains the best planet hunter of its kind, 15 years after it began operations,” explains Nicola Astudillo-Defru (Geneva Observatory – University of Geneva, Switzerland), who co-authored the discovery paper.

Red dwarfs are some of the coolest, faintest — and most common — stars in the Universe. This makes them very good targets in the search for exoplanets and so they are increasingly being studied. In fact, lead author Xavier Bonfils (Institut de Planétologie et d'Astrophysique de Grenoble – Université Grenoble-Alpes/CNRS, Grenoble, France), named their HARPS programme The shortcut to happiness, as it is easier to detect small cool siblings of Earth around these stars, than around stars more similar to the Sun [1].

The red dwarf star Ross 128 in the constellation of Virgo

Many red dwarf stars, including Proxima Centauri, are subject to flares that occasionally bathe their orbiting planets in deadly ultraviolet and X-ray radiation. However, it seems that Ross 128 is a much quieter star, and so its planets may be the closest known comfortable abode for possible life.

Although it is currently 11 light-years from Earth, Ross 128 is moving towards us and is expected to become our nearest stellar neighbour in just 79 000 years — a blink of the eye in cosmic terms. Ross 128 b will by then take the crown from Proxima b and become the closest exoplanet to Earth!

Zooming in on Ross 128

With the data from HARPS, the team found that Ross 128 b orbits 20 times closer than the Earth orbits the Sun. Despite this proximity, Ross 128 b receives only 1.38 times more irradiation than the Earth. As a result, Ross 128 b’s equilibrium temperature is estimated to lie between -60 and 20°C, thanks to the cool and faint nature of its small red dwarf host star, which has just over half the surface temperature of the Sun. While the scientists involved in this discovery consider Ross 128b to be a temperate planet, uncertainty remains as to whether the planet lies inside, outside, or on the cusp of the habitable zone, where liquid water may exist on a planet’s surface [2].

Astronomers are now detecting more and more temperate exoplanets, and the next stage will be to study their atmospheres, composition and chemistry in more detail. Vitally, the detection of biomarkers such as oxygen in the very closest exoplanet atmospheres will be a huge next step, which ESO’s Extremely Large Telescope (ELT) is in prime position to take [3].

Flying through the Ross 128 planetary system

“New facilities at ESO will first play a critical role in building the census of Earth-mass planets amenable to characterisation. In particular, NIRPS, the infrared arm of HARPS, will boost our efficiency in observing red dwarfs, which emit most of their radiation in the infrared. And then, the ELT will provide the opportunity to observe and characterise a large fraction of these planets,” concludes Xavier Bonfils.

Notes:

[1] A planet orbiting close to a low-mass red dwarf star has a larger gravitational effect on the star than a similar planet orbiting further out from a more massive star like the Sun. As a result, this “reflex motion” velocity is much easier to spot. However, the fact that red dwarfs are fainter makes it harder to collect enough signal for the very precise measurements that are needed.

[2] The habitable zone is defined by the range of orbits around a star in which a planet can possess the appropriate temperature for liquid water to exist on the planet’s surface.

[3] This is only possible for the very few exoplanets that are close enough to the Earth to be angularly resolved from their stars.

More information:

This research was presented in a paper entitled “A temperate exo-Earth around a quiet M dwarf at 3.4 parsecs”, by X. Bonfils et al., to appear in the journal Astronomy & Astrophysics.

The team is composed of X. Bonfils (Univ. Grenoble Alpes, CNRS, IPAG, Grenoble, France [IPAG]), N. Astudillo-Defru (Observatoire de Genève, Université de Genève, Sauverny, Switzerland), R. Díaz (CONICET – Universidad de Buenos Aires, Instituto de Astronomía y Física del Espacio (IAFE), Buenos Aires, Argentina), J.-M. Almenara (Observatoire de Genève, Université de Genève, Sauverny, Switzerland), T. Forveille (IPAG), F. Bouchy (Observatoire de Genève, Université de Genève, Sauverny, Switzerland), X. Delfosse (IPAG), C. Lovis (Observatoire de Genève, Université de Genève, Sauverny, Switzerland), M. Mayor (Observatoire de Genève, Université de Genève, Sauverny, Switzerland), F. Murgas (Instituto de Astrofísica de Canarias, La Laguna, Tenerife, Spain), F. Pepe (Observatoire de Genève, Université de Genève, Sauverny, Switzerland), N. C. Santos (Instituto de Astrofísica e Ciências do Espaço and Universidade do Porto, Portugal), D. Ségransan (Observatoire de Genève, Université de Genève, Sauverny, Switzerland), S. Udry (Observatoire de Genève, Université de Genève, Sauverny, Switzerland) and A. Wü̈nsche (IPAG)

ESO is the foremost intergovernmental astronomy organisation in Europe and the world’s most productive ground-based astronomical observatory by far. It is supported by 16 countries: Austria, Belgium, Brazil, the Czech Republic, Denmark, France, Finland, Germany, Italy, the Netherlands, Poland, Portugal, Spain, Sweden, Switzerland and the United Kingdom, along with the host state of Chile and by Australia as a strategic partner. ESO carries out an ambitious programme focused on the design, construction and operation of powerful ground-based observing facilities enabling astronomers to make important scientific discoveries. ESO also plays a leading role in promoting and organising cooperation in astronomical research. ESO operates three unique world-class observing sites in Chile: La Silla, Paranal and Chajnantor. At Paranal, ESO operates the Very Large Telescope and its world-leading Very Large Telescope Interferometer as well as two survey telescopes, VISTA working in the infrared and the visible-light VLT Survey Telescope. ESO is also a major partner in two facilities on Chajnantor, APEX and ALMA, the largest astronomical project in existence. And on Cerro Armazones, close to Paranal, ESO is building the 39-metre Extremely Large Telescope, the ELT, which will become “the world’s biggest eye on the sky”.

Links:

ESOcast 137 Light: Temperate Planet Orbiting Quiet Red Dwarf: http://www.eso.org/public/videos/eso1736a/

Research paper in Astronomy & Astrophysics: https://www.eso.org/public/archives/releases/sciencepapers/eso1736/eso1736a.pdf

Photos of the ESO 3.6-metre telescope: https://www.eso.org/public/images/archive/search/?adv=&subject_name=3.6

More information about HARPS: https://www.eso.org/public/teles-instr/lasilla/36/harps/

ESO’s High Accuracy Radial velocity Planet Searcher (HARPS): https://www.eso.org/public/teles-instr/lasilla/36/harps/

ESO’s Extremely Large Telescope (ELT): https://www.eso.org/elt/

Images, Text, Credits: ESO/Richard Hook/M. Kornmesser/Geneva Observatory – University of Geneva/Nicola Astudillo-Defru/Institut de Planétologie et d'Astrophysique de Grenoble – Université Grenoble-Alpes/CNRS/Xavier Bonfils/Digitized Sky Survey 2. Acknowledgement: Davide De Martin/IAU and Sky & Telescope/Videos: ESO/M. Kornmesser/Digitized Sky Survey 2/Nick Risinger (skysurvey.org).

Best regards, Orbiter.ch

The Changing Colors of our Living Planet

NASA logo.

Nov. 14, 2017

Life. It's the one thing that, so far, makes Earth unique among the thousands of other planets we've discovered. Since the fall of 1997, NASA satellites have continuously and globally observed all plant life at the surface of the land and ocean. During the week of Nov. 13-17, NASA is sharing stories and videos about how this view of life from space is furthering knowledge of our home planet and the search for life on other worlds.

NASA satellites can see our living Earth breathe.

In the Northern Hemisphere, ecosystems wake up in the spring, taking in carbon dioxide and exhaling oxygen as they sprout leaves — and a fleet of Earth-observing satellites tracks the spread of the newly green vegetation.

Meanwhile, in the oceans, microscopic plants drift through the sunlit surface waters and bloom into billions of carbon dioxide-absorbing organisms — and light-detecting instruments on satellites map the swirls of their color.

This fall marks 20 years since NASA has continuously observed not just the physical properties of our planet, but the one thing that makes Earth unique among the thousands of other worlds we’ve discovered: Life.

Satellites measured land and ocean life from space as early as the 1970s. But it wasn't until the launch of the Sea-viewing Wide Field-of-view Sensor (SeaWiFS) in 1997 that the space agency began what is now a continuous, global view of both land and ocean life. A new animation captures the entirety of this 20-year record, made possible by multiple satellites, compressing a decades-long view of life on Earth into a captivating few minutes.

“These are incredibly evocative visualizations of our living planet,” said Gene Carl Feldman, an oceanographer at NASA’s Goddard Space Flight Center in Greenbelt, Maryland. “That’s the Earth, that is it breathing every single day, changing with the seasons, responding to the Sun, to the changing winds, ocean currents and temperatures."

Our Living Planet From Space

Video above: Since the fall of 1997, NASA satellites have continuously and globally observed all plant life at the surface of the land and ocean. Twenty years of satellite data has helped scientists track phytoplankton populations in the ocean, study changing vegetation in the Arctic reaches of North America, monitor crop yields and more. Video Credits: NASA's Goddard Space Flight Center.

The space-based view of life allows scientists to monitor crop, forest and fisheries health around the globe. But the space agency's scientists have also discovered long-term changes across continents and ocean basins. As NASA begins its third decade of global ocean and land measurements, these discoveries point to important questions about how ecosystems will respond to a changing climate and broad-scale changes in human interaction with the land.

Satellites have measured the Arctic getting greener, as shrubs expand their range and thrive in warmer temperatures. Observations from space help determine agricultural production globally, and are used in famine early warning detection. As ocean waters warm, satellites have detected a shift in phytoplankton populations across the planet's five great ocean basins — the expansion of "biological deserts" where little life thrives. And as concentrations of carbon dioxide in the atmosphere continue to rise and warm the climate, NASA's global understanding of plant life will play a critical role in monitoring carbon as it moves through the Earth system.

Life on Earth, from space

Animation above: From space, satellites can see Earth breathe. A new NASA visualization shows 20 years of continuous observations of plant life on land and at the
ocean’s surface, from September 1997 to September 2017. On land, vegetation appears on a scale from brown (low vegetation) to dark green (lots
of vegetation); at the ocean surface, phytoplankton are indicated on a scale from purple (low) to yellow (high). This visualization was created with
data from satellites including SeaWiFS, and instruments including the NASA/NOAA Visible Infrared Imaging Radiometer Suite and the Moderate Resolution Imaging Spectroradiometer. Video Credit: NASA.

Sixty years ago, people were not sure that Earth’s surface could be seen clearly from space. Many thought that the dust particles and other aerosols in the atmosphere would scatter the light, masking the oceans and continents, said Jeffrey Masek, chief of the Biospheric Sciences Laboratory at NASA Goddard.

The Gemini and Apollo programs demonstrated otherwise. Astronauts used specialized cameras to take pictures of Earth that show the beauty and complexity of our living planet, and helped kickstart the era of Earth science research from space. In 1972, the first Landsat mission began its 45-year record of vegetation and land cover.

“As the satellite archive expands, you see more and more dynamics emerging,” Masek said. “We’re now able to look at long-term trends.”

The grasslands of Senegal, for example, undergo drastic seasonal changes. Grasses and shrubs flourish during the rainy season from June to November, then dry up when the rain stops. With early weather satellite data in the 1970s and '80s, NASA Goddard scientist Compton Tucker was able to see that greening and die-back from space, measuring the chlorophyll in the plants below. He developed a way of comparing satellite data from two wavelengths, which gives a quantitative measurement of this greenness called the Normalized Difference Vegetation Index.

“We were astounded when we saw the first images. They were amazing because they showed how vegetation changed annually, year after year,” Tucker said, noting that others were surprised as well when the study came out in 1985. “When we produced this paper, people accused us of ‘painting by numbers,’ or fudging data. But for the first time, you could study vegetation from space based on their photosynthetic capacity.”

When the temperature is right, and water and sunlight are available, plants photosynthesize and produce vegetative material. Leaves strongly absorb blue and red light but reflect near-infrared light back into space. By comparing the ratio of red to near-infrared light, Tucker and his colleagues could quantify the vegetation covering the land.

Expanding these observations to the rest of the globe, the scientists could track the impact on plants of rainy and dry seasons elsewhere in Africa, see the springtime blooms in North America, and the after-effects of wildfires in forests worldwide.

But land is only part of the story. At the base of the ocean’s food web is phytoplankton — tiny organisms that, like land plants, turn water and carbon dioxide into sugar and oxygen, aided by the right combination of nutrients and sunlight.

Animation above: The SeaWiFS satellite was launched in late 1997, just in time to capture the phytoplankton that bloomed in the Eastern Equatorial Pacific as conditions changed from El Niño to La Niña, seen here in yellow. Animation Credit: NASA.

Satellites that can monitor the subtle changes in color of the ocean have helped scientists track changes in phytoplankton populations across the globe. The first view of ocean color came from the Coastal Zone Color Scanner, a proof-of concept instrument launched in 1979. Continuous observations of ocean color began with the launch of SeaWIFS in late 1997. The satellite was just in time to capture the transition from El Niño to La Niña conditions in 1998 — revealing just how quickly and dramatically phytoplankton respond to changing ocean conditions. 

“The entire Eastern Pacific, from the coast of South America all the way to the dateline, transitioned from what was the equivalent of a biological desert to a thriving rainforest. And we watched it happen in real time,” Feldman said. “For me, that was the first demonstration of the power of this kind of observation, to see how the ocean responds to one of the most significant environmental perturbations it could experience, over the course of just a few weeks. It also showed that the ocean and all the life within it is amazingly resilient — if given half a chance.”

Tracking change from satellites

With 20 years of satellite data tracking ocean plant life on a global scale, scientists are investigating how habitats and ecosystems are responding to changing environmental conditions.

Recent studies of ocean life have shown that a long-term trend of rising sea surface temperatures is causing ocean regions known as “biological deserts” to expand. These regions of low phytoplankton growth occur in the center of large, slow-moving currents called gyres.

“As the surface waters warm, it creates a stronger boundary between the deep, cold, nutrient-rich waters and the sunlit, generally nutrient-poor surface waters,” Feldman said. This prevents nutrients from reaching phytoplankton at the surface, and could have significant consequences for fisheries and the marine ecosystem.

In the Arctic Ocean, an explosion of phytoplankton indicates change. As seasonal sea ice melts, warming waters and more sunlight will trigger a sudden, massive phytoplankton bloom that feeds birds, sea lions and newly hatched fish. But with warming atmospheric temperatures, that bloom is now happening several weeks early — before the animals are in place to take advantage of it.

“It’s not just the amount of food, it’s the location and timing that are just as critical,” Feldman said. “Spring bloom is coming earlier, and that’s going to impact the ecosystem in ways we don’t yet understand.”

The climate is warming fastest in Arctic regions, and the impacts on land are visible from space as well. The tundra of Western Alaska, Quebec and elsewhere is turning greener as shrubs extend their reach northwards.

The neighboring northern forests are changing as well. Massive fires in 2004 and 2015 wiped out millions of acres of forests in Alaska, including spruce forests, noted Chris Potter, a research scientist at NASA’s Ames Research Center in California’s Silicon Valley.

“These fires were amazing in the amount of forest area they burned and how hot they burned,” Potter said. “When the air temperature hits 90 degrees Fahrenheit in late May up there, and all these lightning strikes occurred, the forest burned very extensively — close to rivers, close to villages — and nothing could stop it.”

Animation above: Vegetation in North America wakes up in the spring, captured here as a change from pale green to dark green as photosynthesis ramps up with the season. White areas are covered in snow. Animation Credit: NASA.

Satellites help scientists routinely map fires, deforestation and other changes, and to analyze their impact on the carbon cycle, Potter said. Giant fires release many tons of carbon dioxide into the atmosphere, both from the charred trees and moss but also, especially in northern latitudes, from the soils. Potter and colleagues went to the burned areas of Central Alaska this year to measure the underlying permafrost — the thick mossy layer had burned off, exposing the previously frozen soils.

“It’s like taking the insulating layer off a cooler,” he said. “The ice melts underneath and it becomes a slushy mess.”

Forest types can change too, whether it’s after wildfires, insect infestations or other disturbance. The Alaskan spruce forests are being replaced with birch. Potter and his colleagues are also keeping an eye on California forests burned in recent fires, where the concern is that pines will be replaced by oaks.

“When drought is accentuated with these record high temperatures, nothing good seems to come from that for the existing forest type,” he said. “I think we’re seeing real clear evidence of climate causing land-cover change.”

Keeping an eye on crops

Changing temperatures and rainfall patterns also influence crops, whether they are grown in California or Africa. The “greenness” measurement that scientists use to measure forests and grasslands can also be used for agriculture, to monitor the health of fields throughout the growing season.

Researchers and policy makers realized this potential early. One of the first applications of Landsat data in the 1970s was to predict grain yields in Russia and better understand commodities markets. In 1985, food security analysts from USAID approached NASA to incorporate satellite images into their Famine Early Warning Systems Network, to identify regions where food production has been limited by drought. That partnership continues today. With rainfall estimates, vegetation measurements, as well as the recent addition of soil moisture information, NASA scientists can help organizations like USAID direct emergency help.

With improved data from Landsat, the MODIS instruments on NASA's Terra and Aqua spacecraft and other satellites, and by combining data from multiple sensors, researchers are now able to track the growth of crops in individual fields, Tucker said.

“This moves things down to the field sizes for probably 80 percent of the fields globally — this is a huge advancement,” Tucker said.

The view from space not only helps monitor crops, but can help improve agricultural practices as well. A winery in California, for example, uses individual pixels of Landsat data to determine when to irrigate and how much water to use.

Image above: Visualization from September 2017 showing plant life on land and at the ocean’s surface. On land, vegetation appears on a scale from brown (low vegetation) to dark green (lots of vegetation); at the ocean surface, phytoplankton are indicated on a scale from purple (low) to yellow (high). This visualization was created with data from satellites including SeaWiFS, and instruments including the NASA/NOAA Visible Infrared Imaging Radiometer Suite and the Moderate Resolution Imaging Spectroradiometer. Image Credit: NASA.

The next step for NASA scientists is actually looking at the process of photosynthesis from space. When plants undergo that chemical process, some of the absorbed energy fluoresces faintly back, notes Joanna Joiner, a NASA Goddard research scientist. With satellites that detect signals in the very specific wavelengths of this fluorescence, and a fine-tuned analysis technique that blocks out background signals, Joiner and her colleagues can see where and when plants start converting sunlight into sugars.

“It was kind of a revelation that yes, you can measure it,” Joiner said. An early study looked at the U.S. Corn Belt and found it fluoresces “like crazy,” she said. “Those plants have some of the highest fluorescence rates on Earth at their peak.”

Joiner and Tucker are using both the fluorescence data and vegetation indices to get the most information possible about plant growth at regional and global scales: “One of the big questions that still remains is how much carbon are the plants taking up, why does it vary year to year, and which areas are contributing to that variability,” Joiner said

Whether it’s crops, forests or phytoplankton blooms, NASA scientists are tracking life on Earth. Just as satellites help researchers study the atmosphere, rainfall and other physical characteristics of the planet, the ever-improving view from above will allow them to study the interconnected life of the planet, Feldman said.

“This is the capability that will allow us to understand how Earth’s biology responds to a changing planet,” he said.

Related links:

Climate: https://www.nasa.gov/subject/3127/climate

Earth: https://www.nasa.gov/topics/earth/index.html

Ames Research Center: https://www.nasa.gov/centers/ames/home/index.html

Goddard Space Flight Center: https://www.nasa.gov/centers/goddard/home/index.html

Animations (mentioned), Images (mentioned), Video (mentioned), Text, Credits: NASA/Rob Garner/Goddard Space Flight Center, by Kate Ramsayer.

Best regards, Orbiter.ch

Robotic Arm Reaches Out and Grapples Cygnus at Station

NASA / Orbital ATK - CRS OA-8 Cygnus patch.

November 14, 2017

Robotic Arm Reaches Out and Grapples Cygnus
 

Orbital ATK's Cygnus Rendzevous and Installation to the International Space Station

At 5:04 a.m., Expedition 53 Flight Engineers Paolo Nespoli of ESA (European Space Agency) and Randy Bresnik of NASA successfully captured Orbital ATK’s Cygnus cargo spacecraft using the International Space Station’s robotic arm. Robotic ground controllers will position Cygnus for installation to the orbiting laboratory’s Earth-facing port of the Unity module.

Image above: The Canadarm2 robotic arm is seen grappling the Orbital ATK Cygnus resupply ship on Nov. 14, 2017. Image Credit: NASA TV.

Cygnus Installed on Station With New Science Experiments

The Orbital ATK Cygnus cargo ship was bolted into place on the International Space Station’s Earth-facing port of the Unity module at 7:15 a.m. EST. The spacecraft will spend about three weeks attached to the space station before departing in early December. After it leaves the station, the uncrewed spacecraft will deploy several CubeSats before its fiery re-entry into Earth’s atmosphere as it disposes of several tons of trash.

Image above: Nov. 14, 2017: International Space Station Configuration. Five spaceships are parked at the space station including the Orbital ATK Cygnus, the Progress 67 and 68 resupply ships and the Soyuz MS-05 and MS-06 crew ships. image Credit: NASA.

The spacecraft’s arrival brings close to 7,400 pounds of research and supplies to support Expedition 53 and 54. Highlights include:

- The coli AntiMicrobial Satellite (EcAMSat) mission, which will investigate the effect of microgravity on the antibiotic resistance of E. coli, a bacterial pathogen responsible for urinary tract infection in humans and animals. Antibiotic resistance could pose a danger to astronauts, especially since microgravity has been shown to weaken human immune response. The experiment will expose two strains of E. coli to three different doses of antibiotics; one of these strains is deficient in the gene responsible for the increased antibiotic resistance in microgravity. Results from this investigation could help determine appropriate antibiotic dosages to protect astronaut health during long-duration missions and help us understand how antibiotic effectiveness may be increased in microgravity, as well as on Earth.

- The Optical Communications and Sensor Demonstration (OCSD) project, which will study high-speed optical transmission of data and small spacecraft proximity operations. It will test functionality of laser-based communications using CubeSats that provide a compact version of the technology. Results from OCSD could lead to significantly enhanced communication speeds between space and Earth and a better understanding of laser communication between small satellites in low-Earth orbit.

- The Biological Nitrogen Fixation in Microgravity via Rhizobium-Legume Symbiosis (Biological Nitrogen Fixation) investigation, which will examine how low-gravity conditions affect the nitrogen fixation process of Microclover, a resilient and drought tolerant legume. The nitrogen fixation process, a process by which nitrogen in the atmosphere is converted into a usable form for living organisms, is a crucial element of any ecosystem necessary for most types of plant growth. This investigation could provide information on the space viability of the legume’s ability to use and recycle nutrients and give researchers a better understanding of this plant’s potential uses on Earth.

- The Integrated Solar Array and Reflectarray Antenna (ISARA), a hybrid solar power panel and communication solar antenna that can send and receive messages, will test the use of this technology in CubeSat-based environmental monitoring. ISARA may provide a solution for sending and receiving information to and from faraway destinations, both on Earth and in space.

Related links:

The coli AntiMicrobial Satellite (EcAMSat): https://www.nasa.gov/centers/ames/engineering/projects/ecamsat

The Optical Communications and Sensor Demonstration (OCSD): https://www.nasa.gov/directorates/spacetech/small_spacecraft/ocsd_project.html

The Biological Nitrogen Fixation in Microgravity via Rhizobium-Legume Symbiosis (Biological Nitrogen Fixation) : https://www.nasa.gov/mission_pages/station/research/experiments/2717.html

The Integrated Solar Array and Reflectarray Antenna (ISARA): https://www.jpl.nasa.gov/cubesat/isara.php

Learn more about the Orbital ATK CRS-8 mission by going to the mission home page at: http://www.nasa.gov/orbitalatk.

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

Images (mentioned), Video (NASA TV), Text, Credits: NASA/Mark Garcia.

Greetings, Orbiter.ch

Record luminosity: well done LHC

CERN - European Organization for Nuclear Research logo.

13 Nov 2017

Image above: View of the LHC tunnel. (Image : Maximilien Brice/CERN).

It’s the end of the road for the protons this year after a magnificent performance from the Large Hadron Collider (LHC). On Friday, the final beams of the 2017 proton run circulated in the LHC. The run ended, as it does every year, with a round up of the luminosity performance, the indicator by which the effectiveness of a collider is measured and on which the operators keep a constant eye.

The LHC has far exceeded its target for 2017. It has provided its two major experiments, ATLAS and CMS, with 50 inverse femtobarns of data, i.e. 5 billion million million collisions. The inverse femtobarn (fb^-1) is the unit used to measure integrated luminosity, or the cumulative number of potential collisions over a given period.

This result is all the more remarkable because the machine experts had to overcome a serious setback. A vacuum problem in the beam pipe of a magnet cell limited the number of bunches that could circulate in the machine. Several teams were brought in to find a solution. Notably, the arrangement of the bunches in the beams was changed. After a few weeks, luminosity started to increase again.

At the same time, over the course of the year, the operators have optimised the operating parameters. Using a new system put in place this year, they have notably reduced the size of the beams when they meet at the centre of the experiments. The more squeezed the beams, the more collisions occur each time they meet. Last year, the operators managed to obtain 40 collisions at each bunch crossing, with each bunch containing 100 billion particles. In 2017, up to 60 collisions were produced at each crossing.

Thanks to these improvements, the instantaneous luminosity record was smashed, reaching 2.06 x 10³⁴cm^-2s^-1, or twice the nominal value. Instantaneous luminosity corresponds to the potential number of collisions per second.

Graphic above: Graphs showing the integrated luminosity of the LHC in 2017. The unit is the inverse femtobarn. The green squares represent the achieved luminosity, while the blue line shows the planned luminosity. (Image: CERN).

The LHC will continue to operate for another two weeks for two special runs including a week for operation studies. The first special run will consist of carrying out proton collisions at 5.02 TeV (as opposed to the usual 13 TeV), the same energy as that planned for next year’s lead-ion runs. This will enable physicists to collect data with protons, which they will then be able to compare with the lead-ion data.

The second special run, at very low luminosity, will provide data for the TOTEM and ATLAS/ALFA experiments. These two experiments use detectors located on either side of two large LHC detectors: CMS in the case of TOTEM and ATLAS in the case of ATLAS/ALFA. They study interactions called elastic scattering, where two protons merely change direction slightly when they interact, rather than colliding. For these studies, the LHC makes the beams as wide as possible. What’s more, the energy will be limited to 450 GeV, i.e. the energy at which beams are injected from the accelerator complex into the LHC.

Finally, the operators will carry out a “machine development” campaign. Over a week, they will perform operating tests to improve the accelerator’s performance still further (it can never be too good) and begin to prepare the High-Luminosity LHC, which will take over from the LHC after 2025.

When these tests are over, the operators will stop the machine for the year-end technical shutdown.

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 22 Member States.

Related links:

Large Hadron Collider (LHC): http://home.cern/topics/large-hadron-collider

High-Luminosity LHC: http://home.cern/topics/high-luminosity-lhc

TOTEM: https://home.cern/about/experiments/totem

ATLAS/ALFA: http://atlas-project-lumi-fphys.web.cern.ch/atlas-project-lumi-fphys/ALFA/

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

Image (mentioned), Graphic (mentioned), Text, Credits: CERN/Corinne Pralavorio.

Best regards, Orbiter.ch

China’s Sulfur Dioxide Emissions Drop, India’s Grow Over Last Decade

NASA Goddard Space Flight Center logo.

Nov. 13, 2017

A new study by researchers at NASA and the University of Maryland indicates that India may be the world’s top sulfur dioxide emitter.

Sulfur dioxide is an air pollutant that causes acid rain, haze and many health-related problems. It is produced predominantly when coal is burned to generate electricity.

Image above: Sulfur dioxide concentrations for India have increased between 2005 and 2016. Image Credits: NASA’s Earth Observatory/Jesse Allen.

Although China and India remain the world’s largest consumers of coal, the new research found that China’s sulfur dioxide emissions fell by 75 percent since 2007, while India’s emissions increased by 50 percent. The results suggest that India is becoming, if it is not already, the world’s top sulfur dioxide emitter.

“The rapid decrease of sulfur dioxide emissions in China far exceeds expectations and projections,” said first author Can Li, an associate research scientist in the University of Maryland’s Earth System Science Interdisciplinary Center and at NASA’s Goddard Space Flight Center in Greenbelt, Maryland. “This suggests that China is implementing sulfur dioxide controls beyond what climate modelers have taken into account.”

The study was published in the journal Scientific Reports on November 9, 2017.

China and India are the world’s top consumers of coal, which typically contains up to 3 percent sulfur. Most of the two countries’ sulfur dioxide emissions come from coal-fired power plants and coal-burning factories. In particular, Beijing suffers from severe haze problems because of the many coal-burning factories and power plants located nearby and upwind.

Starting in the early 2000s, China began implementing policies such as fining polluters, setting emission reduction goals and lowering emissions limits. According to the results of the current study, these efforts are paying off.

“Sulfur dioxide levels in China declined dramatically even though coal usage increased by approximately 50 percent and electricity generation grew by over 100 percent,” explained Li. “This suggests that much of the reduction is coming from controlling emissions.”

Despite China’s 75 percent drop in sulfur dioxide emissions, recent work by other scientists has shown that the country’s air quality remains poor and continues to cause significant health problems. This may be because sulfur dioxide contributes to only approximately 10 to 20 percent of the air particles that cause haze, according to Li.

“If China wants to bring blue skies back to Beijing, the country needs to also control other air pollutants,” Li said.

By contrast, India’s sulfur dioxide emissions increased by 50 percent over the past decade. The country opened its largest coal-fired power plant in 2012 and has yet to implement emission controls like China.

“Right now, India’s increased sulfur dioxide emissions are not causing as many health or haze problems as they do in China because the largest emission sources are not in the most densely populated area of India,” Li said. “However, as demand for electricity grows in India, the impact may worsen.”

To generate an accurate profile of emissions over India and China for the current study, the researchers combined emissions data generated by two different methods.

First, the researchers collected estimated emission amounts from inventories of the number of factories, power plants, automobiles and other contributors to sulfur dioxide emissions. These inventories, while important data sources, are often incomplete, outdated or otherwise inaccurate in developing countries. They also cannot account for changing conditions or unforeseen policies.

The researchers’ second data source was the Ozone Monitoring Instrument (OMI) on NASA’s Aura satellite, which detects a variety of atmospheric pollutants including sulfur dioxide. While OMI can collect up-to-date information and spot emission sources missing from the inventories, it can only detect relatively large emission sources. In addition, clouds or other atmospheric conditions can interfere with its measurements.

To overcome these challenges, Li and his colleagues collaborated with researchers from Environment and Climate Change Canada to develop better algorithms to quantify emissions based on OMI data. In addition, University of Maryland Department of Atmospheric and Oceanic Science Professors Russell Dickerson and Zhanqing Li, co-authors of the paper, used a weather aircraft to measure the concentrations of sulfur dioxide and other air pollutants over one of the most polluted regions in China. These measurements were used to confirm that the upwind coal power plants were efficiently scrubbing SO2 from their exhaust stacks.

By combining the OMI and inventory data, the researchers generated a more accurate estimate than either data source alone. Previously published studies, which relied on inventory data and published policies, projected that China’s sulfur dioxide emissions would not fall to current levels until 2030 at the earliest.

“Those studies did not reflect the true situation on the ground,” said Li, who is also a member of the U.S. OMI Science Team. “Our study highlights the importance of using satellite measurements to study air quality, especially in regions where conditions may change rapidly and unexpectedly.”

Image above: Sulfur dioxide concentrations for China have decreased between 2005 and 2016. Image Credits: NASA’s Earth Observatory/Jesse Allen.

Li hopes the current study’s results can be used to improve climate and atmospheric models by providing more accurate input data.

This work was performed in collaboration with Argonne National Laboratory, Environment and Climate Change Canada, Michigan Technological University and NOAA. This study used data from OMI, which is a Dutch/Finnish contribution to the NASA Aura mission and managed by the Royal Meteorological Institute of the Netherlands and the Netherlands Space Agency.

To read the paper, visit: https://www.nature.com/articles/s41598-017-14639-8

Aura: https://www.nasa.gov/subject/3184/aura

Earth Research Findings: https://www.nasa.gov/subject/7782/earth-research-findings

Images (mentioned), Text, Credits: NASA/Karl Hille/University of Maryland, story written by Irene Ying.

Greetings, Orbiter.ch

Listening for Gravitational Waves Using Pulsars

JPL - Jet Propulsion Laboratory logo.

Nov. 13, 2017

One of the most spectacular achievements in physics so far this century has been the observation of gravitational waves, ripples in space-time that result from masses accelerating in space. So far, there have been five detections of gravitational waves, thanks to the Laser Interferometer Gravitational-Wave Observatory (LIGO) and, more recently, the European Virgo gravitational-wave detector. Using these facilities, scientists have been able to pin down the extremely subtle signals from relatively small black holes and, as of October, neutron stars.

Image above: This computer simulation shows the collision of two black holes, which produces gravitational waves. Image Credit: SXS.

But there are merging objects far larger whose gravitational wave signals have not yet been detected: supermassive black holes, more than 100 million times more massive than our Sun. Most large galaxies have a central supermassive black hole. When galaxies collide, their central black holes tend to spiral toward each other, releasing gravitational waves in their cosmic dance. Much as a large animal like a lion produces a deeper roar than a tiny mouse's squeak, merging supermassive black holes create lower-frequency gravitational waves than the relatively small black holes LIGO and similar ground-based experiments can detect.

"Observing low-frequency gravitational waves would be akin to being able to hear bass singers, not just sopranos," said Joseph Lazio, chief scientist for NASA's Deep Space Network, based at NASA's Jet Propulsion Laboratory, Pasadena, California, and co-author of a new study in Nature Astronomy.

To explore this uncharted area of gravitational wave science, researchers look not to human-made machines, but to a natural experiment in the sky called a pulsar timing array. Pulsars are dense remnants of dead stars that regularly emit beams of radio waves, which is why some call them "cosmic lighthouses." Because their rapid pulse of radio emission is so predictable, a large array of well-understood pulsars can be used to measure extremely subtle abnormalities, such as gravitational waves. The North American Nanohertz Observatory for Gravitational Waves (NANOGrav), a Physics Frontier Center of the National Science Foundation, is one of the leading groups of researchers using pulsars to search for gravitational waves.

The new Nature Astronomy study concerns supermassive black hole binaries -- systems of two of these cosmic monsters. For the first time, researchers surveyed the local universe for galaxies likely to host these binaries, then predicted which black hole pairs are the likeliest to merge and be detected while doing so. The study also estimates how long it will take to detect one of these mergers.

"By expanding our pulsar timing array over the next 10 years or so, there is a high likelihood of detecting gravitational waves from at least one supermassive black hole binary," said Chiara Mingarelli, lead study author, who worked on this research as a Marie Curie postdoctoral fellow at Caltech and JPL, and is now at the Flatiron Institute in New York.

Mingarelli and colleagues used data from the 2 Micron All-Sky Survey (2MASS), which surveyed the sky from 1997 to 2001, and galaxy merger rates from the Illustris simulation project, an endeavor to make large-scale cosmological simulations. In their sample of about 5,000 galaxies, scientists found that about 90 would have supermassive black holes most likely to merge with another black hole.

While LIGO and similar experiments detect objects in the final seconds before they merge, pulsar timing arrays are sensitive to gravitational wave signals from supermassive black holes that are spiraling toward each other and will not combine for millions of years. That's because galaxies merge hundreds of millions of years before the central black holes they host combine to make one giant supermassive black hole.

Researchers also found that while bigger galaxies have bigger black holes and produce stronger gravitational waves when they combine, these mergers also happen fast, shortening the time period for detection. For example, black holes merging in the large galaxy M87 would have a 4-million-year window of detection. By contrast, in the smaller Sombrero Galaxy, black holes mergers typically take about 160 million years, offering more opportunities for pulsar timing arrays to detect gravitational waves from them.

Black hole mergers generate gravitational waves because, as they orbit each other, their gravity distorts the fabric of space-time, sending ripples outward in all directions at the speed of light. These distortions actually shift the position of Earth and the pulsars ever so slightly, resulting in a characteristic and detectable signal from the array of celestial lighthouses.

"A difference between when the pulsar signals should arrive, and when they do arrive, can signal a gravitational wave," Mingarelli said. "And since the pulsars we study are about 3,000 light-years away, they act as a galactic-scale gravitational-wave detector."

Because all supermassive black holes are so distant, gravitational waves, which travel at the speed of light, take a long time to arrive at Earth. This study looked at supermassive black holes within about 700 million light-years, meaning waves from a merger between any two of them would take up to that long to be detected here by scientists. By comparison, about 650 million years ago, algae flourished and spread rapidly in Earth's oceans -- an event important to the evolution of more complex life.

Many open questions remain about how galaxies merge and what will happen when the Milky Way approaches Andromeda, the nearby galaxy that will collide with ours in about 4 billion years.

"Detecting gravitational waves from billion-solar-mass black hole mergers will help unlock some of the most persistent puzzles in galaxy formation," said Leonidas Moustakas, a JPL research scientist who wrote an accompanying "News and Views" article in the journal.

2MASS was funded by NASA's Office of Space Science, the National Science Foundation, the U.S. Naval Observatory and the University of Massachusetts. JPL managed the program for NASA's Office of Space Science, Washington. Data was processed at IPAC at Caltech in Pasadena, California.

Black Holes: https://www.nasa.gov/subject/6895/black-holes

Pulsars: https://www.nasa.gov/subject/8731/pulsars

Image (mentioned), Text, Credits: NASA/Tony Greicius/JPL/Elizabeth Landau.

Best regards, Orbiter.ch

Sierra Nevada Corporation’s Dream Chaser Achieves Successful Free Flight at NASA Armstrong

Sierra Nevada Corp. - Dream Chaser patch.

Nov. 13, 2017

Sierra Nevada Corp.’s Dream Chaser spacecraft underwent a successful free-flight test on November 11, 2017 at NASA’s Armstrong Flight Research Center, Edwards, California. The test verified and validated the performance of the Dream Chaser in the critical final approach and landing phase of flight, meeting expected models for a future return from the International Space Station.

The flight test helped advance the vehicle under NASA’s Commercial Crew Program space act agreement, as well as helped prepare the vehicle for service under NASA’s Commercial Resupply Services 2 program. The testing will validate the aerodynamic properties, flight software and control system performance of the Dream Chaser.

Image above: Sierra Nevada Corp’s Dream Chaser lands on Edwards Air Force Base in California. The spacecraft went through preparations for flight at NASA’s Armstrong Flight Research Center. Image Credits: NASA/Carla Thomas.

The Dream Chaser is preparing to deliver cargo to the International Space Station beginning in 2019. The data that SNC gathered from this test campaign will help influence and inform the final design of the cargo Dream Chaser, which will fly at least six cargo delivery missions to and from the space station by 2024.

Commercial Space: http://www.nasa.gov/exploration/commercial/index.html

Sierra Nevada Corp.: https://www.sncorp.com/

Image (mentioned), Text, Credits: NASA/Yvonne Gibbs/Armstrong Flight Research Center/Leslie Williams.

Greetings, Orbiter.ch