[Spacetalk] http://www.nasa.gov/index.html

Fri May 22 06:31:08 CDT 2015

Good morning all,
 I hope you have had a wonderful week, they go so fast and for many of you school is almost over...I know you are looking forward to the break although I know most will either teach during the summer or have other jobs so you will be as busy as ever....the visit to Missouri and Freedom Elementary was awesome....although a very full two days...this school is 3rd-5th grades, 800 students....I managed to see them all, visit classrooms, and even had lunch with the kids...it is so much fun and they are so appreciative...I feel so fortunate to be able to share the excitement of the space program while also encouraging them to chase their dreams, establish goals, and believe in themselves...I know the listen and so many are thrilled with the time we share....I post pictures on facebook, gabe gabrielle, if you would like to see them....I wish to thank Kelly and Amber for all their help...they had it scheduled so I could see all the kids and I know it takes allot of effort to make this happen....we have our big Holiday in the US, Memorial Day, when we recognize all those who have given the ultimate sacrifice for us and for our country, to ensure we have this wonderful freedom to live our lives in such a special environment...so many take it for granted but we are indeed very fortunate to live where we can be free, where the opportunities are endless, where we should feel safe, and where we can chase our dreams with confidence they can be achieved....Have a wonderful weekend....we have to always remember to do our best, enjoy everything we do, live in the present, make each day special, let those we care about most know....this is so important because we should never miss an opportunity to express our love and care of those who brighten our lives... keep things in perspective, smile & have fun! Gabe

Memorial Day is a federal holiday in the United States for remembering the people who died while serving in the country's armed forces.

NASA's WISE Spacecraft Discovers Most Luminous Galaxy in Universe
 <http://www.nasa.gov/sites/default/files/thumbnails/image/wise_j224607.57-052635.0.jpg>
This artist's concept depicts the current record holder for the most luminous galaxy in the universe. The galaxy, WISE J224607.57-052635.0, is erupting with light equal to more than 300 trillion suns. It was discovered using data from NASA's WISE mission.
Credits: NASA/JPL-Caltech
A remote galaxy shining with the light of more than 300 trillion suns has been discovered using data from NASA's Wide-field Infrared Survey Explorer (WISE). The galaxy is the most luminous galaxy found to date and belongs to a new class of objects recently discovered by WISE -- extremely luminous infrared galaxies, or ELIRGs.
"We are looking at a very intense phase of galaxy evolution," said Chao-Wei Tsai of NASA's Jet Propulsion Laboratory (JPL) in Pasadena, California, lead author of a new report appearing in the May 22 issue of The Astrophysical Journal. "This dazzling light may be from the main growth spurt of the galaxy’s black hole."
The brilliant galaxy, known as WISE J224607.57-052635.0, may have a behemoth black hole at its belly, gorging itself on gas. Supermassive black holes draw gas and matter into a disk around them, heating the disk to roaring temperatures of millions of degrees and blasting out high-energy, visible, ultraviolet, and X-ray light. The light is blocked by surrounding cocoons of dust. As the dust heats up, it radiates infrared light.
Immense black holes are common at the cores of galaxies, but finding one this big so “far back” in the cosmos is rare. Because light from the galaxy hosting the black hole has traveled 12.5 billion years to reach us, astronomers are seeing the object as it was in the distant past. The black hole was already billions of times the mass of our sun when our universe was only a tenth of its present age of 13.8 billion years.
The new study outlines three reasons why the black holes in the ELIRGs could have grown so massive. First, they may have been born big. In other words, the "seeds," or embryonic black holes, might be bigger than thought possible.
"How do you get an elephant?" asked Peter Eisenhardt, project scientist for WISE at JPL and a co-author on the paper. "One way is start with a baby elephant."
The other two explanations involve either breaking or bending the theoretical limit of black hole feeding, called the Eddington limit. When a black hole feeds, gas falls in and heats up, blasting out light. The pressure of the light actually pushes the gas away, creating a limit to how fast the black hole can continuously scarf down matter. If a black hole broke this limit, it could theoretically balloon in size at a breakneck pace. Black holes have previously been observed breaking this limit; however, the black hole in the study would have had to repeatedly break the limit to grow this large.
Alternatively, the black holes might just be bending this limit.
"Another way for a black hole to grow this big is for it to have gone on a sustained binge, consuming food faster than typically thought possible," said Tsai. "This can happen if the black hole isn't spinning that fast."
If a black hole spins slowly enough, it won't repel its meal as much. In the end, a slow-spinning black hole can gobble up more matter than a fast spinner.
"The massive black holes in ELIRGs could be gorging themselves on more matter for a longer period of time," said Andrew Blain of University of Leicester in the United Kingdom, a co-author of this report. "It's like winning a hot-dog-eating contest lasting hundreds of millions of years."
More research is needed to solve this puzzle of these dazzlingly luminous galaxies. The team has plans to better determine the masses of the central black holes. Knowing these objects’ true hefts will help reveal their history, as well as that of other galaxies, in this very crucial and frenzied chapter of our cosmos.
WISE has been finding more of these oddball galaxies in infrared images of the entire sky captured in 2010. By viewing the whole sky with more sensitivity than ever before, WISE has been able to catch rare cosmic specimens that might have been missed otherwise.
The new study reports a total of 20 new ELIRGs, including the most luminous galaxy found to date. These galaxies were not found earlier because of their distance, and because dust converts their powerful visible light into an incredible outpouring of infrared light.
"We found in a related study with WISE that as many as half of the most luminous galaxies only show up well in infrared light," said Tsai.
JPL manages and operates WISE for NASA's Science Mission Directorate in Washington. The spacecraft was put into hibernation mode in 2011, after it scanned the entire sky twice, thereby completing its main objectives. In September 2013, WISE was reactivated, renamed NEOWISE and assigned a new mission to assist NASA's efforts to identify potentially hazardous near-Earth objects.
The technical paper is online at: http://arxiv.org/abs/1410.1751  For more information on WISE, visit: http://www.nasa.gov/wise

Hubble Observes One-of-a-Kind Star Nicknamed ‘Nasty’
Astronomers using NASA’s Hubble Space Telescope have uncovered surprising new clues about a hefty, rapidly aging star whose behavior has never been seen before in our Milky Way galaxy. In fact, the star is so weird that astronomers have nicknamed it “Nasty 1,” a play on its catalog name of NaSt1. The star may represent a brief transitory stage in the evolution of extremely massive stars.
 <http://www.nasa.gov/sites/default/files/thumbnails/image/p1521a1.jpg>
Astronomers using NASA’s Hubble Space Telescope have uncovered surprising new clues about a hefty, rapidly aging star whose behavior has never been seen before in our Milky Way galaxy.
Credits: NASA/Hubble
First discovered several decades ago, Nasty 1 was identified as a Wolf-Rayet star, a rapidly evolving star that is much more massive than our sun. The star loses its hydrogen-filled outer layers quickly, exposing its super-hot and extremely bright helium-burning core.
But Nasty 1 doesn’t look like a typical Wolf-Rayet star. The astronomers using Hubble had expected to see twin lobes of gas flowing from opposite sides of the star, perhaps similar to those emanating from the massive star Eta Carinae, which is a Wolf-Rayet candidate. Instead, Hubble revealed a pancake-shaped disk of gas encircling the star. The vast disk is nearly 2 trillion miles wide, and may have formed from an unseen companion star that snacked on the outer envelope of the newly formed Wolf-Rayet.  Based on current estimates, the nebula surrounding the stars is just a few thousand years old, and as close as 3,000 light-years from Earth.
“We were excited to see this disk-like structure because it may be evidence for a Wolf-Rayet star forming from a binary interaction,” said study leader Jon Mauerhan of the University of California, Berkeley. “There are very few examples in the galaxy of this process in action because this phase is short-lived, perhaps lasting only a hundred thousand years, while the timescale over which a resulting disk is visible could be only ten thousand years or less.”
In the team’s proposed scenario, a massive star evolves very quickly, and as it begins to run out of hydrogen, it swells up. Its outer hydrogen envelope becomes more loosely bound and vulnerable to gravitational stripping, or a type of stellar cannibalism, by a nearby companion star. In that process, the more compact companion star winds up gaining mass, and the original massive star loses its hydrogen envelope, exposing its helium core to become a Wolf-Rayet star.
Another way Wolf-Rayet stars are said to form is when a massive star ejects its own hydrogen envelope in a strong stellar wind streaming with charged particles. The binary interaction model where a companion star is present is gaining traction because astronomers realize that at least 70 percent of massive stars are members of double-star systems. Direct mass loss alone also cannot account for the number of Wolf-Rayet stars relative to other less-evolved massive stars in the galaxy.
“We’re finding that it is hard to form all the Wolf-Rayet stars we observe by the traditional wind mechanism, because mass loss isn’t as strong as we used to think,” said Nathan Smith of the University of Arizona in Tucson, who is a co-author on the new NaSt1 paper. “Mass exchange in binary systems seems to be vital to account for Wolf-Rayet stars and the supernovae they make, and catching binary stars in this short-lived phase will help us understand this process.”
But the mass transfer process in mammoth binary systems isn’t always efficient. Some of the stripped matter can spill out during the gravitational tussle between the stars, creating a disk around the binary.
“That’s what we think is happening in Nasty 1,” Mauerhan said. “We think there is a Wolf-Rayet star buried inside the nebula, and we think the nebula is being created by this mass-transfer process. So this type of sloppy stellar cannibalism actually makes Nasty 1 a rather fitting nickname.”
The star’s catalogue name, NaSt1, is derived from the first two letters of each of the two astronomers who discovered it in 1963, Jason Nassau and Charles Stephenson.
Viewing the Nasty 1 system hasn’t been easy. The system is so heavily cloaked in gas and dust, it blocks even Hubble’s view of the stars. Mauerhan’s team cannot measure the mass of each star, the distance between them, or the amount of material spilling onto the companion star.
Previous observations of Nasty 1 have provided some information on the gas in the disk. The material, for example, is travelling about 22,000 miles per hour in the outer nebula, slower than similar stars. The comparatively slow speed indicates that the star expelled its material through a less violent event than Eta Carinae’s explosive outbursts, where the gas is travelling hundreds of thousands of miles per hour.
Nasty 1 may also be shedding the material sporadically. Past studies in infrared light have shown evidence for a compact pocket of hot dust very close to the central stars. Recent observations by Mauerhan and colleagues at the University of Arizona, using the Magellan telescope at Las Campanas Observatory in Chile, have resolved a larger pocket of cooler dust that may be indirectly scattering the light from the central stars. The presence of warm dust implies that it formed very recently, perhaps in spurts, as chemically enriched material from the two stellar winds collides at different points, mixes, flows away, and cools. Sporadic changes in the wind strength or the rate the companion star strips the main star’s hydrogen envelope might also explain the clumpy structure and gaps seen farther out in the disk.
To measure the hypersonic winds from each star, the astronomers turned to NASA’s Chandra X-ray Observatory. The observations revealed scorching hot plasma, indicating that the winds from both stars are indeed colliding, creating high-energy shocks that glow in X-rays. These results are consistent with what astronomers have observed from other Wolf-Rayet systems.
The chaotic mass-transfer activity will end when the Wolf-Rayet star runs out of material. Eventually, the gas in the disk will dissipate, providing a clear view of the binary system.
“What evolutionary path the star will take is uncertain, but it will definitely not be boring,” said Mauerhan. “Nasty 1 could evolve into another Eta Carinae-type system. To make that transformation, the mass-gaining companion star could experience a giant eruption because of some instability related to the acquiring of matter from the newly formed Wolf-Rayet. Or, the Wolf-Rayet could explode as a supernova. A stellar merger is another potential outcome, depending on the orbital evolution of the system. The future could be full of all kinds of exotic possibilities depending on whether it blows up or how long the mass transfer occurs, and how long it lives after the mass transfer ceases.”
The team’s results will appear May 21 in the online edition of the Monthly Notices of the Royal Astronomical Society.
The Hubble Space Telescope is a project of international cooperation between NASA and the European Space Agency. NASA's Goddard Space Flight Center in Greenbelt, Maryland, manages the telescope. The Space Telescope Science Institute (STScI) in Baltimore, Maryland, conducts Hubble science operations. STScI is operated for NASA by the Association of Universities for Research in Astronomy, Inc., in Washington.
For images and more information about Nasty 1 and the Hubble Space Telescope, visit:
  http://www.nasa.gov/hubble
  http://hubblesite.org/news/2015/21

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