Runaway Stars Leave Infrared Waves in Space

NASA - Spitzer Space Telescope logo / NASA - WISE Mission patch.

Jan. 5, 2016

Astronomers are finding dozens of the fastest stars in our galaxy with the help of images from NASA's Spitzer Space Telescope and Wide-field Infrared Survey Explorer, or WISE.

When some speedy, massive stars plow through space, they can cause material to stack up in front of them in the same way that water piles up ahead of a ship. Called bow shocks, these dramatic, arc-shaped features in space are leading researchers to uncover massive, so-called runaway stars.

Images above: Bow shocks thought to mark the paths of massive, speeding stars are highlighted in these images from NASA's Spitzer Space Telescope and Wide-field Infrared Survey Explorer, or WISE. Images Credits: NASA/JPL-Caltech/University of Wyoming.

"Some stars get the boot when their companion star explodes in a supernova, and others can get kicked out of crowded star clusters," said astronomer William Chick from the University of Wyoming in Laramie, who presented his team's new results at the American Astronomical Society meeting in Kissimmee, Florida. "The gravitational boost increases a star's speed relative to other stars."

Our own sun is strolling through our Milky Way galaxy at a moderate pace. It is not clear whether our sun creates a bow shock. By comparison, a massive star with a stunning bow shock, called Zeta Ophiuchi (or Zeta Oph), is traveling around the galaxy faster than our sun, at 54,000 mph (24 kilometers per second) relative to its surroundings. Zeta Oph's giant bow shock can be seen in this image from the WISE mission:

http://www.nasa.gov/mission_pages/WISE/multimedia/gallery/pia13455.html

Both the speed of stars moving through space and their mass contribute to the size and shapes of bow shocks. The more massive a star, the more material it sheds in high-speed winds. Zeta Oph, which is about 20 times as massive as our sun, has supersonic winds that slam into the material in front of it.

The result is a pile-up of material that glows. The arc-shaped material heats up and shines with infrared light. That infrared light is assigned the color red in the many pictures of bow shocks captured by Spitzer and WISE.

Chick and his team turned to archival infrared data from Spitzer and WISE to identify new bow shocks, including more distant ones that are harder to find. Their initial search turned up more than 200 images of fuzzy red arcs. They then used the Wyoming Infrared Observatory, near Laramie, to follow up on 80 of these candidates and identify the sources behind the suspected bow shocks. Most turned out to be massive stars.

Spitzer Space Telescope. Image Credit: NASA

The findings suggest that many of the bow shocks are the result of speedy runaways that were given a gravitational kick by other stars. However, in a few cases, the arc-shaped features could turn out to be something else, such as dust from stars and birth clouds of newborn stars. The team plans more observations to confirm the presence of bow shocks.

"We are using the bow shocks to find massive and/or runaway stars," said astronomer Henry "Chip" Kobulnicky, also from the University of Wyoming. "The bow shocks are new laboratories for studying massive stars and answering questions about the fate and evolution of these stars."

Another group of researchers, led by Cintia Peri of the Argentine Institute of Radio Astronomy, is also using Spitzer and WISE data to find new bow shocks in space. Only instead of searching for the arcs at the onset, they start by hunting down known speedy stars, and then they scan them for bow shocks.

Wide-field Infrared Survey Explorer, or WISE. Image Credit: NASA

"WISE and Spitzer have given us the best images of bow shocks so far," said Peri. "In many cases, bow shocks that looked very diffuse before, can now be resolved, and, moreover, we can see some new details of the structures."

Some of the first bow shocks from runaway stars were identified in the 1980s by David Van Buren of NASA's Jet Propulsion Laboratory in Pasadena, California. He and his colleagues found them using infrared data from the Infrared Astronomical Satellite (IRAS), a predecessor to WISE that scanned the whole infrared sky in 1983.

Kobulnicky and Chick belong to a larger team of researchers and students studying bow shocks and massive stars, including Matt Povich from the California State Polytechnic University, Pomona. The National Science Foundation funds their research.

Images from Spitzer, WISE and IRAS are archived at the NASA Infrared Science Archive housed at the Infrared Processing and Analysis Center at the California Institute of Technology in Pasadena. Caltech manages JPL for NASA.

More information about Spitzer is online at:

http://www.nasa.gov/spitzer

http://spitzer.caltech.edu

More information about WISE is at:

http://www.nasa.gov/wise

Images (mentioned), Text, Credits: NASA/Martin Perez/JPL/Whitney Clavin.

Best regards, Orbiter.ch

Chandra Finds Supermassive Black Hole Burping Nearby

NASA - Chandra X-ray Observatory patch.

Jan. 5, 2016

Evidence for powerful blasts produced by a giant black hole has been discovered using NASA’s Chandra X-ray Observatory. This is one of the nearest supermassive black holes to Earth that is currently undergoing such violent outbursts.

Astronomers found this outburst in the supermassive black hole centered in the small galaxy NGC 5195. This companion galaxy is merging with a large spiral galaxy NGC 5194, also known as “The Whirlpool.” Both of these galaxies are in the Messier 51 galaxy system, located about 26 million light years from Earth.

Image above: Galaxy NGC 5195. Image Credits: X-ray: NASA/CXC/Univ of Texas/E.Schlegel et al; Optical: NASA/STScI.

“For an analogy, astronomers often refer to black holes as 'eating' stars and gas.  Apparently, black holes can also burp after their meal,” said Eric Schlegel of The University of Texas in San Antonio, who led the study. “Our observation is important because this behavior would likely happen very often in the early universe, altering the evolution of galaxies. It is common for big black holes to expel gas outward, but rare to have such a close, resolved view of these events.”

In the Chandra data, Schlegel and his colleagues detect two arcs of X-ray emission close to the center of NGC 5195.

“We think these arcs represent fossils from two enormous blasts when the black hole expelled material outward into the galaxy,” said co-author Christine Jones of the Harvard-Smithsonian Center for Astrophysics (CfA) in Cambridge, Mass. “This activity is likely to have had a big effect on the galactic landscape.”

Just outside the outer X-ray arc, the researchers detected a slender region of emission of relatively cool hydrogen gas in an optical image from the Kitt Peak National Observatory 0.9-meter telescope. This suggests that the hotter, X-ray emitting gas has “snow-plowed,” or swept up, the hydrogen gas from the center of the galaxy. This is a clear case where a supermassive black hole is affecting its host galaxy in a phenomenon that astronomers call “feedback.”

In NGC 5195, the properties of the gas around the X-ray-glowing arcs suggest that the outer arc has plowed up enough material to trigger the formation of new stars.

“We think that feedback keeps galaxies from becoming too large,” said co-author Marie Machacek of CfA. “But at the same time, it can be responsible for how some stars form. This shows that black holes can create, not just destroy.”

The astronomers think the outbursts of the supermassive black hole in NGC 5195 may have been triggered by the interaction of this smaller galaxy with its large spiral companion, causing gas to be funneled in towards the black hole. The energy generated by this infalling matter would produce the outbursts. The team estimates that it took about one to three million years for the inner arc to reach its current position, and three to six million years for the outer arc.

Artist's view of Chandra X-ray Observatory. Image Credits: NASA/CXC

The arcs are also significant because of their location in the galaxy. They are well outside the region where rapid outflow, or winds, have been detected from active supermassive black holes in other galaxies, yet inside the much larger cavities and filaments observed in the hot gas around many massive galaxies.  As such they may represent a rare view an intermediate stage in the feedback process operating between the interstellar gas and the black hole.

These results were presented in January 2016 at the 227th meeting of the American Astronomical Society meeting in Kissimmee, FL, and have been submitted in a paper to The Astrophysical Journal. Laura Vega, of the Fisk University and Vanderbilt University Bridge Program, in Nashville, Tennessee was also a co-author of the paper. NASA's Marshall Space Flight Center in Huntsville, Alabama, manages the Chandra program for NASA's Science Mission Directorate in Washington. The Smithsonian Astrophysical Observatory in Cambridge, Massachusetts, controls Chandra's science and flight operations.

Read More from NASA's Chandra X-ray Observatory: http://chandra.harvard.edu/photo/2016/ngc5195/

For more Chandra images, multimedia and related materials, visit: http://www.nasa.gov/chandra

Images (mentioned), Text, Credits: NASA/Lee Mohon/Marshall Space Flight Center/Molly Porter.

Best regards, Orbiter.ch

Andromeda in High-Energy X-rays

NASA - NuSTAR Mission patch.

Jan. 5, 2016

Image above: NASA's Nuclear Spectroscope Telescope Array, or NuSTAR, has imaged a swath of the Andromeda galaxy -- the nearest large galaxy to our own Milky Way galaxy. Image Credits: NASA/JPL-Caltech/GSFC.

NASA's Nuclear Spectroscopic Telescope Array, or NuSTAR, has captured the best high-energy X-ray view yet of a portion of our nearest large, neighboring galaxy, Andromeda. The space mission has observed 40 "X-ray binaries" -- intense sources of X-rays comprised of a black hole or neutron star that feeds off a stellar companion.

The results will ultimately help researchers better understand the role of X-ray binaries in the evolution of our universe. According to astronomers, these energetic objects may play a critical role in heating the intergalactic bath of gas in which the very first galaxies formed.

"Andromeda is the only large spiral galaxy where we can see individual X-ray binaries and study them in detail in an environment like our own," said Daniel Wik of NASA Goddard Space Flight Center in Greenbelt, Maryland, who presented the results at the 227th meeting of American Astronomical Society in Kissimmee, Florida.­­­­ "We can then use this information to deduce what's going on in more distant galaxies, which are harder to see."

Andromeda, also known as M31, can be thought of as the big sister to our own Milky Way galaxy. Both galaxies are spiral in shape, but Andromeda is slightly larger than the Milky Way in size. Lying 2.5 million light-years away, Andromeda is relatively nearby in cosmic terms. It can even be seen by the naked eye in dark, clear skies.

Other space missions, such as NASA's Chandra X-ray Observatory, have obtained crisper images of Andromeda at lower X-ray energies than the high-energy X-rays detected by NuSTAR. The combination of Chandra and NuSTAR provides astronomers with a powerful tool for narrowing in on the nature of the X-ray binaries in spiral galaxies. 

In X-ray binaries, one member is always a dead star or remnant formed from the explosion of what was once a star much more massive than the sun. Depending on the mass and other properties of the original giant star, the explosion may produce either a black hole or neutron star. Under the right circumstances, material from the companion star can "spill over" its outermost edges and then be caught by the gravity of the black hole or neutron star. As the material falls in, it is heated to blazingly high temperatures, releasing a huge amount of X-rays.

With NuSTAR's new view of a swath of Andromeda, Wik and colleagues are working on identifying the fraction of X-ray binaries harboring black holes versus neutron stars. That research will help them understand the population as a whole.

"We have come to realize in the past few years that it is likely the lower-mass remnants of normal stellar evolution, the black holes and neutron stars, may play a crucial role in heating of the intergalactic gas at very early times in the universe, around the cosmic dawn," said Ann Hornschemeier of NASA Goddard, the principal investigator of the NuSTAR Andromeda studies.

"Observations of local populations of stellar-mass-sized black holes and neutron stars with NuSTAR allow us to figure out just how much power is coming out from these systems."

NASA's Nuclear Spectroscopic Telescope Array, or NuSTAR. Image Credits: NASA/GFSC

The new research also reveals how Andromeda may differ from our Milky Way. Fiona Harrison, the principal investigator of the NuSTAR mission, added, "Studying the extreme stellar populations in Andromeda tells us about how its history of forming stars may be different than in our neighborhood."

Harrison will be presenting the 2015 Rossi Prize lecture at the AAS meeting. The prize, awarded by the AAS's High-Energy Astrophysics Division, honors physicist Bruno Rossi, an authority on cosmic-ray physics and a pioneer in the field of X-ray astronomy.

Related links:

Harrison will be presenting the 2015 Rossi Prize lecture: http://www.jpl.nasa.gov/news/news.php?feature=4447

AAS's High-Energy Astrophysics Division: http://head.aas.org/

For more information, visit http://www.nasa.gov/nustar and http://www.nustar.caltech.edu/

Images (mentioned), Text, Credits: NASA/Martin Perez/JPL/Whitney Clavin.

Greetings, Orbiter.ch

Tim Peake set for spacewalk

ESA - Principia Mission patch.

5 January 2016

December spacewalk

ESA astronaut Tim Peake and NASA astronaut Tim Kopra will exit the International Space Station next week to repair a power unit on the outside.

The two Tims arrived at the Space Station on 15 December but this will be their second involvement in a spacewalk: Tim Peake assisted Tim Kopra and Station commander Scott Kelly when they moved an equipment carrier on 21 December.

Tim Peake training at JSC

The new spacewalk will last around six hours on 15 January, with Tim Kopra and Tim Peake working closely together to replace a faulty unit.

The ESA astronaut explains: “Our primary task will be to replace a failed Solar Shunt Unit, which transfers electrical power generated by the solar panels.”

The unit is relatively easy to replace because it is a simple box that can be removed by undoing one bolt. Once done, the spacewalkers will lay cables in advance of new docking ports and reinstall a valve that was removed for the relocation of the Leonardo module last year.

Preparing for spacewalk

Inside the Station, Scott Kelly will help the spacewalkers into and out of their suits – a major operation in itself.

Before the astronauts leave they will breathe pure oxygen for two hours to purge their bodies of nitrogen. The spacesuit pressure is lower than in the Space Station and the drop could give them the ‘bends’, much like scuba divers rising too quickly to the sea surface.

Donning their spacesuits and safety equipment will take hours before they enter the airlock to reduce the pressure until it is safe to open the exterior hatch.

Tim Peake comments, “I am thrilled at this opportunity for a spacewalk. Right now we are focusing on preparing the tools, equipment and procedures. 

Quest airlock

“Maintaining the International Space Station from the outside requires intense operations - not just from the crew, but also from our ground support teams who are striving to make this spacewalk as safe and efficient as possible.”

The Station has eight shunt units to regulate power but has been operating with only seven since last November.

Tim concludes, “If the spacewalk is successful, this will restore the International Space Station to 100% of its operational capability.”

More information and live updates can be found on Tim Peake’s Principia blog: http://blogs.esa.int/tim-peake/

Related article:

Space Station Module Relocation Makes Way for Commercial Crew Spacecraft:
http://orbiterchspacenews.blogspot.ch/2015/05/space-station-module-relocation-makes.html

Related links:

Principia mission: http://www.esa.int/Our_Activities/Human_Spaceflight/Principia

Connect with Tim Peake: http://timpeake.esa.int/

Principia in UK: https://principia.org.uk/

Images, Text, Credits: ESA/NASA/Bill Stafford.

Greetings, Orbiter.ch

Rover Rounds Martian Dune to Get to the Other Side

NASA - Mars Science Laboratory (MSL) patch.

Jan. 4, 2016

Image above: This Dec. 18, 2015, view of the downwind face of "Namib Dune" on Mars covers 360 degrees, including a portion of Mount Sharp on the horizon. Image Credits: NASA/JPL-Caltech/MSSS.

NASA's Curiosity Mars rover, partway through the first up-close study ever conducted of  extraterrestrial sand dunes, is providing dramatic views of a dune's steep face, where cascading sand has sculpted very different textures than the wavy ripples visible on the dune's windward slope.

Panoramic scenes dominated by the steep face of a dune called "Namib Dune" are online at these sites:

http://www.jpl.nasa.gov/spaceimages/details.php?id=PIA20284

http://www.jpl.nasa.gov/spaceimages/details.php?id=PIA20281

Researchers are using Curiosity to examine examples of the Bagnold Dunes, a band of dark sand dunes lining the northwestern flank of Mt. Sharp, the layered mountain the rover is climbing. A characteristic that sets true dunes apart from other wind-shaped bodies of sand, such as drifts and ripples previously visited by Mars rovers, is a steep, downwind slope known as the slip face. Here, sand blowing across the windward side of the dune suddenly becomes sheltered from the wind by the dune itself. The sand falls out of the air and builds up on the slope until it becomes steepened and flows in mini-avalanches down the face.

Image above: This view from NASA's Curiosity Mars Rover shows the downwind side of a dune about 13 feet high within the Bagnold Dunes field on Mars. The rover's Navigation Camera took the component images on Dec. 17, 2015. Image Credits: NASA/JPL-Caltech.

The mission's dune-investigation campaign is designed to increase understanding about how wind moves and sorts grains of sand, in an environment with less gravity and much less atmosphere than well-studied dune fields on Earth. The Bagnold Dunes are active. Sequential images taken from orbit over the course of multiple years show that some of these dunes are migrating by as much as a yard, or meter, per Earth year.

Image above: This Dec. 17, 2015, view combines multiple images from the telephoto-lens camera of the Mast Camera (Mastcam) on NASA's Curiosity Mars rover to reveal fine details of the downwind face of "Namib Dune." Image Credits: NASA/JPL-Caltech/MSSS.

Curiosity has not caught a sand slide in action, but the rover's images of the Namib Dune slip face show where such slides have occurred recently. These dunes likely are most active in Mars' southern summer, rather than in the current late-fall season.

Image above: This Dec. 17, 2015, view combines multiple images from the telephoto-lens camera of the Mast Camera (Mastcam) on NASA's Curiosity Mars rover to reveal fine details of the downwind face of "Namib Dune." Sand on this face of the dark dune has cascaded down a slope of about 26 to 28 degrees. Image Credits: NASA/JPL-Caltech/MSSS.

A few days of rover operations were affected in December due to an arm-motion fault, diagnosed as a minor software issue. Normal use of the arm resumed Dec. 23.

Curiosity has been working on Mars since early August 2012. It reached the base of Mount Sharp in 2014 after fruitfully investigating outcrops closer to its landing site and then trekking to the mountain. The main mission objective now is to examine successively higher layers of Mount Sharp.

For more information about Curiosity, visit: http://mars.jpl.nasa.gov/msl

Images (mentioned), Text, Credits: NASA/Dwayne Brown/Laurie Cantillo/JPL/Guy Webster/Martin Perez.

Happy New Year! Best regards, Orbiter.ch

New Year Begins With Eye to Next Spacewalk

ISS - Expedition 46 Mission patch.

January 4, 2016

The Expedition 46 crew begins its first full week of the New Year planning for a spacewalk scheduled for Jan. 15. The orbiting residents are also busy with numerous science experiments benefitting life on Earth and future astronauts.

Image above: Tropical Cyclone Ula, a category 3 storm at the time this image was captured, is seen from the International Space Station. Image Credit: NASA TV.

A pair of spacewalkers will replace a failed voltage regulator to return power to one of eight power channels next Friday. Two crew members will exit the Quest airlock and work outside for 6.5 hours for the replacement work. They will also rig cables for the future installation of docking adapters that will enable commercial crew vehicles to dock at the International Space Station. Final spacewalking roles will be confirmed following spacesuit hardware checkouts taking place today.

Image above: NASA astronaut Tim Kopra is seen floating during a spacewalk on Dec. 21, 2015. Image Credit: NASA TV.

NASA astronauts Tim Kopra and Commander Scott Kelly collected and stowed blood and urine samples this morning for the Fluid Shifts study. That experiment observes the headward fluid shift caused by microgravity that increases brain pressure and pushes back on the eye. British astronaut Tim Peake also explored particles suspended in fluids, or colloids, which could benefit the design of advanced materials on Earth.

Related links:

Fluid Shifts study: http://www.nasa.gov/mission_pages/station/research/experiments/1257.html

One-Year Crew: https://www.nasa.gov/content/one-year-crew/

Expedition 46: https://blogs.nasa.gov/spacestation/category/expedition-46/

Stay up-to-date on the latest ISS news at: http://www.nasa.gov/station

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

Happy New Year! Greetings, Orbiter.ch

Triple Play

NASA - Cassini Mission to Saturn patch.

Jan. 4, 2016

What looks like a pair of Saturnian satellites is actually a trio upon close inspection.

Here, Cassini has captured Enceladus (313 miles or 504 kilometers across) above the rings and Rhea (949 miles or 1,527 kilometers across) below.  The comparatively tiny speck of Atlas (19 miles or 30 kilometers across) can also be seen just above and to the left of Rhea, and just above the thin line of Saturn's F ring.

This view looks toward the unilluminated side of the rings from about 0.34 degrees below the ring plane.

The image was taken in visible light with the Cassini spacecraft narrow-angle camera on Sept. 24, 2015.

The view was obtained at a distance of approximately 1.8 million miles (2.8 million kilometers) from Rhea. Image scale on Rhea is 10 miles (16 kilometers) per pixel. The distance to Enceladus was 1.3 million miles (2.1 million kilometers) for a scale of 5 miles (8 kilometers) per pixel. The distance to Atlas was 1.5 million miles (2.4 million) kilometers) for an image scale at Atlas of 9 miles (14 kilometers) per pixel.

The Cassini mission is a cooperative project of NASA, ESA (the European Space Agency) and the Italian Space Agency. The Jet Propulsion Laboratory, a division of the California Institute of Technology in Pasadena, manages the mission for NASA's Science Mission Directorate, Washington. The Cassini orbiter and its two onboard cameras were designed, developed and assembled at JPL. The imaging operations center is based at the Space Science Institute in Boulder, Colorado.

For more information about the Cassini-Huygens mission visit http://saturn.jpl.nasa.gov or http://www.nasa.gov/cassini . The Cassini imaging team homepage is at http://ciclops.org and ESA's website: http://www.esa.int/Our_Activities/Space_Science/Cassini-Huygens

Image, Text, Credits: NASA/JPL/Martin Perez.

Happy New Year! Greetings, Orbiter.ch