Surprising Spiral Structure Spotted by ALMA

ESO - European Southern Observatory logo.

10 October 2012

New observations reveal the secrets of a dying star

Curious spiral spotted by ALMA around red giant star R Sculptoris (data visualisation)

Astronomers using the Atacama Large Millimeter/submillimeter Array (ALMA) have discovered a totally unexpected spiral structure in the material around the old star R Sculptoris. This is the first time that such a structure, along with an outer spherical shell, has been found around a red giant star. It is also the first time that astronomers could get full three-dimensional information about such a spiral. The strange shape was probably created by a hidden companion star orbiting the red giant. This work is one of the first ALMA early science results to be published and it appears in the journal Nature this week.

A team using the Atacama Large Millimeter/submillimeter Array (ALMA), the most powerful millimetre/submillimetre telescope in the world, has discovered a surprising spiral structure in the gas around the red giant star R Sculptoris [1][2][3]. This means that there is probably a previously unseen companion star orbiting the star [4]. The astronomers were also surprised to find that far more material than expected had been ejected by the red giant.

The red giant star R Sculptoris in the constellation of Sculptor (The Sculptor)

“We’ve seen shells around this kind of star before, but this is the first time we’ve ever seen a spiral of material coming out from a star, together with a surrounding shell,” says the lead author on the paper presenting the results, Matthias Maercker (ESO and Argelander Institute for Astronomy, University of Bonn, Germany).

Because they blow out large amounts of material, red giants like R Sculptoris are major contributors to the dust and gas that provide the bulk of the raw materials for the formation of future generations of stars, planetary systems and subsequently for life.

Wide-field view of the sky around the red giant star R Sculptoris

Even in the Early Science phase, when the new observations were made, ALMA greatly outperformed other submillimetre observatories. Earlier observations had clearly shown a spherical shell around R Sculptoris, but neither the spiral structure nor a companion was found.

"When we observed the star with ALMA, not even half its antennas were in place. It's really exciting to imagine what the full ALMA array will be able to do once it's completed in 2013," adds Wouter Vlemmings (Chalmers University of Technology, Sweden), a co-author of the study.

Video above: Slicing through a 3D ALMA view of the material around the red giant star R Sculptoris.

Late in their lives, stars with masses up to eight times that of the Sun become red giants and lose a large amount of their mass in a dense stellar wind. During the red giant stage stars also periodically undergo thermal pulses. These are short-lived phases of explosive helium burning in a shell around the stellar core. A thermal pulse leads to material being blown off the surface of the star at a much higher rate, resulting in the formation of a large shell of dust and gas around the star. After the pulse the rate at which the star loses mass falls again to its normal value.

Thermal pulses occur approximately every 10 000 to 50 000 years, and last only a few hundred years. The new observations of R Sculptoris show that it suffered a thermal pulse event about 1800 years ago that lasted for about 200 years. The companion star shaped the wind from R Sculptoris into a spiral structure.

Video above: Slicing through a 3D model of the material around the red giant star R Sculptoris.

“By taking advantage of the power of ALMA to see fine details, we can understand much better what happens to the star before, during and after the thermal pulse, by studying how the shell and the spiral structure are shaped,” says Maercker. “We always expected ALMA to provide us with a new view of the Universe, but to be discovering unexpected new things already, with one of the first sets of observations is truly exciting.” 

In order to describe the observed structure around R Sculptoris, the team of astronomers has also performed computer simulations to follow the evolution of a binary system [5]. These models fit the new ALMA observations very well.

Zooming into the red giant star R Sculptoris

"It’s a real challenge to describe theoretically all the observed details coming from ALMA, but our computer models show that we really are on the right track. ALMA is giving us new insight into what's happening in these stars and what might happen to the Sun in a few billion years from now," says Shazrene Mohamed (Argelander Institute for Astronomy, Bonn, Germany and South African Astronomical Observatory), a co-author of the study.

“In the near future, observations of stars like R Sculptoris with ALMA will help us to understand how the elements we are made up of reached places like the Earth. They also give us a hint of what our own star's far future might be like,” concludes Matthias Maercker.

Video above: Model of the evolution of the material around the old star R Sculptoris over 2000 years.

Notes:

[1] R Sculptoris is an example of an asymptotic giant branch (AGB) star. These are stars with initial masses between 0.8 and 8 solar masses in the late stages of their lives. They are cool, red giants with large mass loss in the form of strong stellar winds, and are typically long-period variables. Their structure consists of a tiny central core of carbon and oxygen surrounded by a helium and hydrogen burning shell, and then an enormous convective envelope. The Sun will eventually evolve into an AGB star.

[2] The ejected shell formed around AGB stars is composed of gas and dust grains. The dust grains can be spotted by looking for thermal emission extending from the far infrared through millimetre wavelengths. At millimetre wavelengths emission from the CO molecule allows astronomers to obtain high-resolution maps of the gas emission from the strong stellar wind generated by the AGB stars. These observations are also excellent tracers of the gas distribution around these objects. The high sensitivity of ALMA makes it possible to directly image the dust condensation zone and the structure of the material around AGB stars, showing details smaller than 0.1 arcsecond.

[3] A similar spiral, but without a surrounding shell, has been seen in NASA/ESA Hubble Space Telescope observations of the star LL Pegasi. But, unlike the new ALMA observations, these data did not allow the full three-dimensional structure to be studied. The Hubble observations detect the dust and ALMA the molecular emission.

[4] Unseen binaries have also been suggested as an explanation for the odd shapes seen in related objects, planetary nebulae. After the AGB phase, intermediate and low-mass stars (0.8–8 solar masses) will end their lives by forming a planetary nebula. These are the glowing remains of the stellar envelope of gas ejected during the AGB phase, which is ionised by ultraviolet radiation emitted by the central star. Many planetary nebulae have extremely complex and varied morphologies. Binary central stars, stellar discs and magnetic fields have been suggested as the mechanism that produces such a variety of shapes.

[5] The system modelled here consists of a primary AGB star going through a thermal pulse and a small companion star. The separation between the stars used in the simulation is 60 astronomical units with a total mass of the system of two solar masses. The orbital period is 350 years.

More information:

This research was presented in a paper, “Unexpectedly large mass loss during the thermal pulse cycle of the red giant star R Sculptoris”, by Maercker et al. to appear in the journal Nature.

The team is composed of M. Maercker (ESO; Argelander Institute for Astronomy, University of Bonn, Germany), S. Mohamed (Argelander Institute for Astronomy; South African Astronomical Observatory, South Africa), W. H. T. Vlemmings (Onsala Space Observatory, Chalmers University of Technology, Onsala, Sweden), S. Ramstedt (Argelander Institute for Astronomy, University of Bonn; Uppsala University), M. A. T. Groenewegen (Royal Observatory of Belgium, Brussels, Belgium), E. Humphreys (ESO), F. Kerschbaum (Department of Astronomy, University of Vienna, Austria), M. Lindqvist (Onsala Space Observatory), H. Olofsson (Onsala Space Observatory), C. Paladini (Department of Astronomy, University of Vienna, Austria), M. Wittkowski (ESO), I. de Gregorio-Monsalvo (Joint ALMA Observatory, Chile) and L. A. Nyman (Joint ALMA Observatory).

The year 2012 marks the 50th anniversary of the founding of the European Southern Observatory (ESO). 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 15 countries: Austria, Belgium, Brazil, the Czech Republic, Denmark, France, Finland, Germany, Italy, the Netherlands, Portugal, Spain, Sweden, Switzerland and the United Kingdom. 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, the world’s most advanced visible-light astronomical observatory and two survey telescopes. VISTA works in the infrared and is the world’s largest survey telescope and the VLT Survey Telescope is the largest telescope designed to exclusively survey the skies in visible light. ESO is the European partner of a revolutionary astronomical telescope ALMA, the largest astronomical project in existence. ESO is currently planning the 39-metre European Extremely Large optical/near-infrared Telescope, the E-ELT, which will become “the world’s biggest eye on the sky”.

The Atacama Large Millimeter/submillimeter Array (ALMA), an international astronomy facility, is a partnership of Europe, North America and East Asia in cooperation with the Republic of Chile. ALMA is funded in Europe by the European Southern Observatory (ESO), in North America by the U.S. National Science Foundation (NSF) in cooperation with the National Research Council of Canada (NRC) and the National Science Council of Taiwan (NSC) and in East Asia by the National Institutes of Natural Sciences (NINS) of Japan in cooperation with the Academia Sinica (AS) in Taiwan. ALMA construction and operations are led on behalf of Europe by ESO, on behalf of North America by the National Radio Astronomy Observatory (NRAO), which is managed by Associated Universities, Inc. (AUI) and on behalf of East Asia by the National Astronomical Observatory of Japan (NAOJ). The Joint ALMA Observatory (JAO) provides the unified leadership and management of the construction, commissioning and operation of ALMA.

The ALMA Observatory will be inaugurated on 13 March 2013.

Links:

    Research paper: http://www.eso.org/public/archives/releases/sciencepapers/eso1239/eso1239a.pdf

    More about ALMA at ESO: http://www.eso.org/public/teles-instr/alma.html

    The Joint ALMA Observatory: http://www.almaobservatory.org/

Images, Text, Credit: ALMA (ESO / NAOJ / NRAO) / IAU and Sky & Telescope / Digitized Sky Survey 2. Acknowledgement: Davide De Martin / Videos: ALMA (ESO / NAOJ / NRAO), L. Calçada / S. Mohamed (SAAO) / A. Fujii/Digitized Sky Survey 2/Nature / M. Maercker et al.

Greetings, Orbiter.ch

SpaceX's Dragon Carrying NASA Cargo Resupplies Space Station

SpaceX - CRS-1 Mission patch.

Oct. 10, 2012


The Space Exploration Technologies Corp. (SpaceX) Dragon spacecraft was berthed to the International Space Station at 8:03 a.m. CDT Wednesday, a key milestone in a new era of commercial spaceflight. The delivery flight is the first contracted resupply mission by the company under NASA's Commercial Resupply Services contract.

Dragon Captured and Berthed to Station

"I want to congratulate SpaceX and the NASA team that worked alongside them to make this happen, and salute the astronauts aboard the space station who successfully captured the Dragon capsule," NASA Administrator Charles Bolden said. "This marks the start of a new era of exploration for the United States, one where we will reduce the cost of missions to low-Earth orbit so we can focus our resources on deep space human missions back around the moon, to an asteroid and eventually to Mars."

Image above: The International Space Station's Canadarm2 installs the SpaceX Dragon cargo craft to the Earth-facing side of the Harmony node. Credit: NASA TV.

Space station Expedition 33 crew members Aki Hoshide of the Japan Aerospace Exploration Agency and Sunita Williams of NASA used the station's robotic arm to successfully capture Dragon at 5:56 a.m. The capture came 2 days, 10 hours, 21 minutes and after the mission's launch. The station was 250 miles above the Pacific Ocean, just west of Baja California.

Station Crew Opens Dragon Hatch

Following its capture, the spacecraft was attached to the Earth-facing port of the Harmony node. The station crew could open the hatch to Dragon as early as Wednesday afternoon to begin unloading its cargo. The capsule is scheduled to spend 18 days attached to the station before returning for a splashdown in the Pacific Ocean off the Southern California coast.

Dragon delivered 882 pounds of supplies to the orbiting laboratory, including 260 pounds of crew supplies, 390 pounds of scientific research, 225 pounds of hardware and several pounds of other supplies. Dragon will return a total of 1,673 pounds, including 163 pounds of crew supplies, 866 pounds of scientific research, and 518 pounds of vehicle hardware and other hardware.

Image above: Commander Suni Williams opens the hatch to the SpaceX Dragon cargo craft. Credit: NASA TV.

Dragon's capability to return cargo from the station is critical for supporting scientific research in the orbiting laboratory's unique microgravity environment, which enables important benefits for humanity and increases understanding of how humans can safely work, live and thrive in space for long periods. The ability to return frozen samples is a first for this flight and will be very helpful to the station's research community. Not since the space shuttle have NASA and its international partners been able to return considerable amounts of research and samples for analysis.

The Dragon spacecraft lifted off from Cape Canaveral Air Force Station in Florida at 8:35 p.m. EDT Sunday aboard a SpaceX Falcon 9 rocket. The mission was the first of at least 12 Space X cargo resupply missions to the space station through 2016. The resupply contract with NASA is worth $1.6 billion.

Dragon spacecraft

"Under President Obama's leadership, the nation is embarking on an ambitious space program that is bringing critical launches back to the United States, in-sourcing American jobs, and keeping the nation on the cutting edge of technology development and innovation, all the while, maintaining America's world leadership and dominance in space exploration," Bolden said.

SpaceX is one of two companies that built and tested new cargo spacecraft under NASA's Commercial Orbital Transportation Services (COTS) program. SpaceX completed its final demonstration test in May when it launched a Dragon capsule to the station and performed a series of checkout maneuvers, before Dragon was grappled by the station crew and installed on the orbiting laboratory.

International Space Station (ISS)

Orbital Sciences is the other company participating in COTS. Orbital's Antares launch vehicle is on the launch pad at Wallops Flight Facility in Virginia. The rocket and pad will undergo a series of fueling tests that will take about three weeks. After the tests are completed, a hot fire test of the Antares first-stage engines will be conducted. A flight test of the Antares with a simulated Cygnus spacecraft will be flown in late 2012. A demonstration flight of Cygnus to the space station is planned in early 2013.

NASA initiatives like COTS and the agency's Commercial Crew Program are helping develop a robust U.S. commercial space transportation industry with the goal of achieving safe, reliable and cost-effective transportation to and from the space station and low-Earth orbit. In addition to cargo flights, NASA's commercial space partners are making progress toward a launch of astronauts from U.S. soil in the next 5 years.

For more information about the International Space Station, visit: http://www.nasa.gov/station

Follow @Astro_Suni on Twitter: http://twitter.com/Astro_Suni

Visit Gateway to Astronaut Photography of Earth: http://eol.jsc.nasa.gov/

Read more about Expedition 33: http://www.nasa.gov/mission_pages/station/expeditions/expedition33/index.html

Images, Videos, Text, Credits: NASA / NASA TV / SpaceX.

Greetings, Orbiter.ch

Testing Mars and Moon soil for sheltering astronauts from radiation

ESA logo.

10 October 2012

Humans venturing beyond Earth orbit deeper into space face increased exposure to cosmic radiation, so ESA has teamed with Germany’s GSI particle accelerator to test potential shielding for astronauts, including Moon and Mars soil.

ESA’s two-year project is assessing the most promising materials for shielding future astronauts going to the Moon, the asteroids or Mars.

Future deep space base

“We are working with the only facility in Europe capable of simulating the high-energy heavy atomic nuclei found in galactic cosmic radiation – the GSI Helmholtz Centre for Heavy Ion Research in Darmstadt, Germany,” explained Alessandra Menicucci, overseeing the project.

“We assessed materials including aluminium, water, polyethylene plastic, multilayer structures and simulated Moon and Mars material – the latter on the basis these will be accessible to planetary expeditions.

“We have also confirmed a new type of hydrogen storage material holds particular promise.”

Lunar soil simulant

The International Space Station orbits within Earth’s magnetic field, safeguarding its occupants from the bulk of space radiation. To venture further out, dedicated shielding will be required.

Space radiation comes from the Sun – in the form of intense but short-lived ‘solar particle events’ – as well as galactic cosmic radiation originating beyond our Solar System: atomic nuclei produced by dying stars, their passage sped by magnetic fields as they cross the galaxy.

“Solar particle events are made up of protons that can be shielded quite simply,” added Alessandra.

“The real challenge for deep-space missions is galactic cosmic radiation, which cannot be shielded completely because of its very high energy, although the exposure level decreases with increased solar activity.

GSI

Most are small protons or helium nuclei, but about 1% are larger, the size of an iron atom or more – known as ‘high-ionising high energy particles’ or HZE for short.

Radiation shielding can be counter-intuitive because denser and thicker does not always mean better.

HZEs striking metal shields can produce showers of secondary particles that might be even more harmful.

Astronauts

And as shield thickness increases, overall the energy loss of ionising radiation rises to a peak then declines rapidly.

“In general, the lighter a material’s atomic nuclei the better the protection,” notes Alessandra.

Water and polyethylene performed better than aluminium for instance, and new hydrogen-rich materials developed by UK company Cella Energy tested better still.

Cella Energy originally developed its patent-pending materials for storing hydrogen fuel but is currently investigating their radiation resistance.

ROSSINI for space radiation protection testing

Formally known as ROSSINI – Radiation Shielding by ISRU (In-Situ Resource Utilisation) and/or Innovative Materials for EVA, Vehicle and Habitat – the project also involves complex ‘Monte Carlo’ simulations to get a statistical overview of radiation effects.

One key resource is the Geant4 toolkit to simulate particles striking matter, developed through a CERN-led international collaboration and also employed on CERN’s Large Hadron Collider.

Moon and Mars material testing

“Simulation results are then compared against test data – an essential stage because this is such a complex field with many unknowns, especially in terms of human biology,” Alessandra says.

“Our completed research will then be available in the planning of manned missions.” 

GSI also provided access to its US counterpart, NASA’s Space Radiation Laboratory at Brookhaven in New York, where the first round of testing was recently performed.

ROSSINI is being managed for ESA by Thales Alenia Space Italy, with GSI performing testing and data analysis and Swiss company SpaceIT working on simulations.

ESA’s cooperation with GSI extends beyond ROSSINI: the Agency will be a major user of its new Facility for Antiproton and Ion Research particle accelerator. When complete, FAIR will give experimental access to an even higher range of particle energies.

Related links:

GSI: http://www.gsi.de/

NASA Space Radiation Laboratory at Brookhaven: http://www.bnl.gov/medical/nasa/nsrl_description.asp

Thales Alenia Space: http://www.thalesgroup.com/Markets/Space/Home/

Cella Energy: http://www.cellaenergy.com/

CERN: http://public.web.cern.ch/public/Welcome.html

Images, Text, Credits: ESA / NASA / GSI / ROSSINI.

Best regards, Orbiter.ch

Large water reservoirs at the dawn of stellar birth

ESA - Herschel Mission patch.

9 October 2012

ESA’s Herschel space observatory has discovered enough water vapour to fill Earth’s oceans more than 2000 times over, in a gas and dust cloud that is on the verge of collapsing into a new Sun-like star.

Stars form within cold, dark clouds of gas and dust – ‘pre-stellar cores’ – that contain all the ingredients to make solar systems like our own.

Water, essential to life on Earth, has previously been detected outside of our Solar System as gas and ice coated onto tiny dust grains near sites of active star formation, and in proto-planetary discs capable of forming alien planetary systems.

Taurus molecular cloud

The new Herschel observations of a cold pre-stellar core in the constellation of Taurus known as Lynds 1544 are the first detection of water vapour in a molecular cloud on the verge of star formation.

More than 2000 Earth oceans-worth of water vapour were detected, liberated from icy dust grains by high-energy cosmic rays passing through the cloud.

“To produce that amount of vapour, there must be a lot of water ice in the cloud, more than three million frozen Earth oceans’ worth,” says Paola Caselli from the University of Leeds, UK, lead author of the paper reporting the results in Astrophysical Journal Letters.

“Before our observations, the understanding was that all the water was frozen onto dust grains because it was too cold to be in the gas phase and so we could not measure it. 

“Now we will need to review our understanding of the chemical processes in this dense region and, in particular, the importance of cosmic rays to maintain some amount of water vapour.”

Water in L1544

The observations also revealed that the water molecules are flowing towards the heart of the cloud where a new star will probably form, indicating that gravitational collapse has just started.

“There is absolutely no sign of stars in this dark cloud today, but by looking at the water molecules, we can see evidence of motion inside the region that can be understood as collapse of the whole cloud towards the centre,” says Dr Caselli.

“There is enough material to form a star at least as massive as our Sun, which means it could also be forming a planetary system, possibly one like ours.”

Some of the water vapour detected in L1544 will go into forming the star, but the rest will be incorporated into the surrounding disc, providing a rich water reservoir to feed potential new planets.

Herschel Space Telescope

“Thanks to Herschel, we can now follow the ‘water trail’ from a molecular cloud in the interstellar medium, through the star formation process, to a planet like Earth where water is a crucial ingredient for life,” says ESA’s Herschel project scientist, Göran Pilbratt.

Related Links:

Herschel: ESA's giant infrared observatory: http://www.esa.int/SPECIALS/Herschel/index.html

Herschel overview: http://www.esa.int/SPECIALS/Herschel/index.html

Online Showcase of Herschel Images OSHI: http://oshi.esa.int/

Herschel in depth: http://sci.esa.int/science-e/www/area/index.cfm?fareaid=16

Herschel Science Centre: http://herschel.esac.esa.int/

Images, Text, Credits: ESA/Herschel/SPIRE/HIFI/Caselli et al.

Greetings, Orbiter.ch

Red Bulls Stratos, the dizzying challenge

Red Bull - Stratos Mission patch.

Oct. 8, 2012

Felix Baumgartner must leap into space 36 kilometers from "terra firma"(earth ground). The challenge, scheduled for Monday, was postponed to Tuesday.

Red Bull Stratos Flight Diagram

The adventurer Austrian daredevil Felix Baumgartner will start Tuesday confines of the atmosphere above New Mexico, hoping to cross the sound barrier and beat the world record skydiving. His attempt, initially scheduled for Monday, was postponed a day because of weather conditions, including temperatures too cold and too much wind in the Roswell area, where there is experience.

Supersonic Freefall - Red Bull Stratos

Felix Baumgartner will first be transported in a capsule attached to a huge helium balloon at an altitude of 36,576 meters record, before jumping into the void, wearing a pressure suit. The Austrian, aged 43, has been training for 5 years for this jump, during which it will be in free fall for 5 minutes before opening his parachute at 1,500 meters. If he manages to cross the sound barrier at 1227.6 km / h, Felix Baumgartner will go as fast as a pistol bullet. The greatest danger is for the adventurer lose control and start rotating on itself, resulting in a loss of consciousness.

Felix Baumgartner

He hopes to fight a series of records, including the highest jump - more than three times the average altitude of an airliner - and the fastest speed attained by a human being in free fall. Red Bull Stratos mission, with a staff of 100 people, also hope, with this jump, contribute to medical research in aeronautics. The record parachute freefall has been held since 1960 by a former colonel in the U.S. Air Force (USAF), Joe Kittinger, who, from a balloon filled with helium, jumped from 31,333 m. The veteran, now aged 83, is also part of Red Bull Stratos mission.

For more information about Felix Baumgartner / Red Bull Stratos, visit: http://www.redbullstratos.com/the-team/felix-baumgartner/

Images, Video, Text, Credits: Red Bull Stratos / Felix Baumgartner / AFP / Translation: Orbiter.ch.

Cheers, Orbiter.ch

SpaceX CRS-1 Launch, NASA Celebrates Milestone Liftoff!

SpaceX - CRS-1 Mission patch.

08 Oct 2012

Commercial Resupply Launch

    Mission: SpaceX CRS-1
    Launch Vehicle: Falcon 9
    Launch Site: Cape Canaveral Air Force Station, Fla.
    Launch Pad: Space Launch Complex 40
    Date: October 7
    Time: 8:35 p.m. EDT

Description: SpaceX CRS-1 will be the first commercial resupply mission to the International Space Station by Space Exploration Technologies (SpaceX).

 SpaceX CRS-1 Launch

The Falcon 9 and Dragon capsule lift off of the pad on a mission to open America's new operational cargo capability to the International Space Station!

SpaceX launched the first of a dozen operational missions to deliver supplies to the International Space Station on Oct. 7 for NASA. Launch time came at 8:35 p.m. from Launch Complex 40 at Cape Canaveral Air Force Station in Florida, just a few miles south of the space shuttle launch pads. The spacecraft will be joined to the station three days later.

Image above: The SpaceX Falcon 9 and Dragon capsule lift off Oct. 7. Photo credit: NASA.

NASA Administrator Charles Bolden and SpaceX President Gwynne Shotwell celebrated the successful liftoff of a landmark cargo mission to the International Space Station tonight as a SpaceX Dragon spacecraft loaded with supplies flew on its own in orbit. The flight is the first operational resupply mission for the company and NASA.

"This was a critical event in spaceflight tonight," Bolden said. "We're once again launching spacecraft from American soil with the supplies our astronauts need in space. NASA and the nation are embarking on an ambitious program of space exploration."

Hawthorne, Calif.-based Space Exploration Technologies, or SpaceX, launched its Dragon capsule aboard a Falcon 9 rocket at 8:35 p.m. EDT, capping a flawless countdown with spectacular show of light and thunder from the rocket's nine engines.

"This was an operational mission, so we're operational (but that) doesn't mean we're going to stop learning and stop making these vehicles as reliable as possible," Shotwell said during a press conference after the launch.

SpaceX Dragon in orbit

Dragon will rendezvous with the orbiting laboratory Wednesday so astronaut and station commander Suni Williams can reach out with the station's robot arm and grapple the Dragon. The spacecraft will then be joined to one of the station's ports where astronauts will unload its 1,000 pounds of materials. They will also load almost 2,000 pounds of used equipment and experiments inside the Dragon to be returned to Earth safely in about three weeks.

For more information about SpaceX, visit: http://www.spacex.com/

Images, Video, Text, Credits: NASA / NASA TV / SpaceX.

Best regards, Orbiter.ch

NASA's Swift Satellite Discovers a New Black Hole in our Galaxy

NASA - SWIFT Mission patch.

Oct. 05, 2012

Image above: Gas flood of gas plunging toward a previously unknown black hole. Credit: NASA's Goddard Space Flight Center.

NASA's Swift satellite recently detected a rising tide of high-energy X-rays from a source toward the center of our Milky Way galaxy. The outburst, produced by a rare X-ray nova, announced the presence of a previously unknown stellar-mass black hole.

"Bright X-ray novae are so rare that they're essentially once-a-mission events and this is the first one Swift has seen," said Neil Gehrels, the mission's principal investigator, at NASA's Goddard Space Flight Center in Greenbelt, Md. "This is really something we've been waiting for."

Video above: An X-ray outburst caught by NASA's Swift on Sept. 16, 2012, resulted from a flood of gas plunging toward a previously unknown black hole. Gas flowing from a sun-like star collects into a disk around the black hole. Normally, this gas would steadily spiral inward. But in this system, named Swift J1745-26, the gas collects for decades before suddenly surging inward. Credit: NASA's Goddard Space Flight Center.

An X-ray nova is a short-lived X-ray source that appears suddenly, reaches its emission peak in a few days and then fades out over a period of months. The outburst arises when a torrent of stored gas suddenly rushes toward one of the most compact objects known, either a neutron star or a black hole.

The rapidly brightening source triggered Swift's Burst Alert Telescope twice on the morning of Sept. 16, and once again the next day.

Named Swift J1745-26 after the coordinates of its sky position, the nova is located a few degrees from the center of our galaxy toward the constellation Sagittarius. While astronomers do not know its precise distance, they think the object resides about 20,000 to 30,000 light-years away in the galaxy's inner region.

Ground-based observatories detected infrared and radio emissions, but thick clouds of obscuring dust have prevented astronomers from catching Swift J1745-26 in visible light.

The nova peaked in hard X-rays -- energies above 10,000 electron volts, or several thousand times that of visible light -- on Sept. 18, when it reached an intensity equivalent to that of the famous Crab Nebula, a supernova remnant that serves as a calibration target for high-energy observatories and is considered one of the brightest sources beyond the solar system at these energies.

Even as it dimmed at higher energies, the nova brightened in the lower-energy, or softer, emissions detected by Swift's X-ray Telescope, a behavior typical of X-ray novae. By Wednesday, Swift J1745-26 was 30 times brighter in soft X-rays than when it was discovered and it continued to brighten.

"The pattern we're seeing is observed in X-ray novae where the central object is a black hole. Once the X-rays fade away, we hope to measure its mass and confirm its black hole status," said Boris Sbarufatti, an astrophysicist at Brera Observatory in Milan, Italy, who currently is working with other Swift team members at Penn State in University Park, Pa.

The black hole must be a member of a low-mass X-ray binary (LMXB) system, which includes a normal, sun-like star. A stream of gas flows from the normal star and enters into a storage disk around the black hole. In most LMXBs, the gas in the disk spirals inward, heats up as it heads toward the black hole, and produces a steady stream of X-rays.

But under certain conditions, stable flow within the disk depends on the rate of matter flowing into it from the companion star. At certain rates, the disk fails to maintain a steady internal flow and instead flips between two dramatically different conditions -- a cooler, less ionized state where gas simply collects in the outer portion of the disk like water behind a dam, and a hotter, more ionized state that sends a tidal wave of gas surging toward the center.

NASA's Swift satellite. Credit: NASA's Goddard Space Flight Center.

"Each outburst clears out the inner disk, and with little or no matter falling toward the black hole, the system ceases to be a bright source of X-rays," said John Cannizzo, a Goddard astrophysicist. "Decades later, after enough gas has accumulated in the outer disk, it switches again to its hot state and sends a deluge of gas toward the black hole, resulting in a new X-ray outburst."

This phenomenon, called the thermal-viscous limit cycle, helps astronomers explain transient outbursts across a wide range of systems, from protoplanetary disks around young stars, to dwarf novae -- where the central object is a white dwarf star -- and even bright emission from supermassive black holes in the hearts of distant galaxies.

Swift, launched in November 2004, is managed by Goddard Space Flight Center. It is operated in collaboration with Penn State, the Los Alamos National Laboratory in New Mexico and Orbital Sciences Corp. in Dulles, Va., with international collaborators in the United Kingdom and Italy and including contributions from Germany and Japan.

Related Links:

Swift website: http://www.nasa.gov/swift

Video on the NASA Explorer YouTube channel: http://www.youtube.com/watch?v=_W-QEs8sKE0

Images (mentioned), Video (mentioned), Text, Credit: NASA's Goddard Space Flight Center / Francis Reddy.

Greetings, Orbiter.ch