NASA - Hubble Space Telescope updates

[Space Pete]

RELEASE: 10-175

NASA's Hubble Shows Hyperfast Star Was Booted From Milky Way

WASHINGTON -- NASA's Hubble Space Telescope has detected a hypervelocity star, a rare phenomenon moving three times faster than our sun.

The star may have been created in a cosmic misstep. A hundred million years ago, a triple-star system was traveling through the bustling center of our Milky Way galaxy when it wandered too close to the galaxy's giant black hole. The black hole captured one of the stars and hurled the other two out of the Milky Way. The two outbound stars merged to form a super-hot blue star traveling at incredible speeds.

This story may seem like science fiction, but Hubble astronomers say it is the most likely scenario for the creation of a so-called hypervelocity star, known as HE 0437-5439. It is one of the fastest ever detected with a speed of 1.6 million mph. Hubble observations confirm that the stellar speedster hails from the Milky Way's core, settling some confusion about the star's original home.

Most of the roughly 16 known hypervelocity stars, all discovered since 2005, are thought to be exiles from the heart of our galaxy. But this Hubble result is the first direct observation linking such a star to an origin in the center of the galaxy.

"Using Hubble, we can for the first time trace back to where the star came from by measuring the star's direction of motion on the sky," said astronomer Warren Brown of the Harvard-Smithsonian Center for Astrophysics in Cambridge, Mass. "Our measurements point directly to the Milky Way center."

Brown, a member of the Hubble team that observed the star, is the lead author on a paper about the finding published online July 20 in the Astrophysical Journal Letters.

Brown said, "These exiled stars are rare in the Milky Way's population of 100 billion stars. For every 100 million stars in the galaxy, there lurks one hypervelocity star."

The stellar outcast already is cruising in the Milky Way's distant outskirts about 200,000 light-years from the galaxy's center. Using Hubble to measure the runaway star's direction and determine the Milky Way's core as its starting point, Brown and Gnedin's team calculated how fast the star had to have been ejected to reach its current location.

"Studying these stars could provide more clues about the nature of some of the universe's unseen mass, and it could help astronomers better understand how galaxies form," said team leader Oleg Gnedin of the University of Michigan in Ann Arbor.

The star's age is another mystery. Based on the speed and position of HE 0437-5439, the star would have to be 100 million years old to have journeyed from the Milky Way's core. Yet its mass -- nine times that of our sun-- and blue color mean that it should have burned out after only 20 million years -- far shorter than the transit time it took to get to its current location.

Astronomers have proposed two possibilities to solve the age problem. The star either dipped into the Fountain of Youth by becoming a blue straggler, or it was flung out of the Large Magellanic Cloud, a neighboring galaxy.

In 2008 a team of astronomers thought they had solved the mystery. They found a match between the exiled star's chemical makeup and the characteristics of stars in the Large Magellanic Cloud. The rogue star's position also is close to the neighboring galaxy, only 65,000 light-years away. The new Hubble result, however, settles the debate over the star's birthplace and places it in the Milky Way.

The most likely explanation for the star's blue color and extreme speed is that it was part of a triple-star system that was involved in a gravitational billiards game with the galaxy's monster black hole. This concept for imparting an escape velocity on stars was first proposed in 1988. The theory predicted the Milky Way's black hole should eject a star about once every 100,000 years.

The triple-star system contained a pair of closely orbiting stars and a third outer member also gravitationally tied to the group. The black hole pulled the outer star away from the tight binary system. The doomed star's momentum was transferred to the stellar twosome, boosting the duo to escape velocity from the galaxy. As the pair rocketed away, they went on with normal stellar evolution.

The more massive companion evolved more quickly, puffing up to become a red giant. It enveloped its partner, and the two stars spiraled together, merging into one superstar, the blue straggler that Hubble observed. A blue straggler is a relatively young, massive star produced by the merger of two lighter-weight stars.

Astronomers used the sharp vision of Hubble's Advanced Camera for Surveys to make two separate observations of the wayward star 3.5 years apart. Team member Jay Anderson of the Space Telescope Science Institute in Baltimore developed a technique to measure the star's position relative to each of 11 distant background galaxies. These background galaxies form a reference frame in which Anderson compared the star's position in 2006 and 2009 to calculate how far it had moved.

"Hubble excels with this type of measurement," Anderson said. "This observation would be challenging to do from the ground."

The team is trying to determine the homes of four other unbound stars, all located on the fringes of the Milky Way.

"We are targeting massive "B" stars, like HE 0437-5439," said Brown, who has discovered 14 of the 16 known hypervelocity stars. "These stars shouldn't live long enough to live in the distant outskirts of the Milky Way, so we shouldn't expect to find them there. But the quantity of stars in the outer region is much less than in the core, so we have a better chance of finding these unusual objects."

For graphics and more information about HE 0437-5439, visit:

www.nasa.gov/hubble

and

http://hubblesite.org/news/2010/19

[rdale]

Following the extraordinarily successful Servicing Mission 4 (SM4) of Hubble Space Telescope (HST) in May of 2009, the Observatory is now fully equipped with a broad array of powerful science instruments that put it at the pinnacle of its scientific power. Relevant to the subject matter of the Beyond 2010 Conference, HST will be well-placed over the next five-plus years to advance our knowledge of the formation of high-redshift galaxies and their growth with cosmic time; the emergence of structure in the early universe via Dark Matter-driven gravitational instability; and the universe's expansion history and any resulting implications for the temporal character of Dark Energy. These are fitting projects for the iconic facility now celebrating its 20th anniversary in orbit.

http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/20100026446_2010028446.pdf

[jacqmans]

News release: 2010-272                                                                      Aug. 19, 2010

Cosmic Lens Used to Probe Dark Energy for First Time

The full version of this story with accompanying images is at:
http://www.jpl.nasa.gov/news/news.cfm?release=2010-272&cid=release_2010-272

PASADENA, Calif. -- Astronomers have devised a new method for measuring perhaps the greatest puzzle of our universe -- dark energy. This mysterious force, discovered in 1998, is pushing our universe apart at ever-increasing speeds.

For the first time, astronomers using NASA's Hubble Space Telescope were able to take advantage of a giant magnifying lens in space -- a massive cluster of galaxies -- to narrow in on the nature of dark energy. Their calculations, when combined with data from other methods, significantly increase the accuracy of dark energy measurements. This may eventually lead to an explanation of what the elusive phenomenon really is.

"We have to tackle the dark energy problem from all sides," said Eric Jullo, an astronomer at NASA's Jet Propulsion Laboratory, Pasadena, Calif. "It's important to have several methods, and now we've got a new, very powerful one." Jullo is lead author of a paper on the findings appearing in the Aug. 20 issue of the journal Science.

Scientists aren't clear about what dark energy is, but they do know that it makes up a large chunk of our universe -- about 72 percent. Another chunk, about 24 percent, is thought to be dark matter, also mysterious in nature but easier to study than dark energy because of its gravitational influence on matter that we can see. The rest of the universe, a mere four percent, is the stuff that makes up people, planets, stars and everything made up of atoms.

In their new study, the science team used images from Hubble to examine a massive cluster of galaxies, named Abell 1689, which acts as a magnifying, or gravitational, lens. The gravity of the cluster causes galaxies behind it to be imaged multiple times into distorted shapes, sort of like a fun house mirror reflection that warps your face.

Using these distorted images, the scientists were able to figure out how light from the more distant, background galaxies had been bent by the cluster -- a characteristic that depends on the nature of dark energy. Their method also depends on precise ground-based measurements of the distance and speed at which the background galaxies are traveling away from us. The team used these data to quantify the strength of the dark energy that is causing our universe to accelerate.

"What I like about our new method is that it's very visual," said Jullo. "You can literally see gravitation and dark energy bend the images of the background galaxies into arcs."

According to the scientists, their method required multiple, meticulous steps. They spent the last several years developing specialized mathematical models and precise maps of the matter -- both dark and "normal" -- constituting the Abell 1689 cluster.

"We can now apply our technique to other gravitational lenses," said co-author Priya Natarajan, a cosmologist at Yale University, New Haven, Conn. "We're exploiting a beautiful phenomenon in nature to learn more about the role that dark energy plays in our universe."

Other authors of the paper include Jean-Paul Kneib and Carlo Schimd of the Université de Provence, France; Anson D’Aloisio of Yale University; Marceau Limousin of Université de Provence and University of Copenhagen, Denmark; and Johan Richard of Durham University, United Kingdom.

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, Md., manages the telescope. The Space Telescope Science Institute, operated for NASA by the Association of Universities for Research in Astronomy, Inc. in Washington, conducts Hubble science operations. More information is online at http://www.nasa.gov/hubble .

The California Institute of Technology in Pasadena manages JPL for NASA. More information is at http://www.jpl.nasa.gov .



- end -

[Space Pete]

New Hubble Observations of Supernova 1987A Trace Shock Wave.

An international team of astronomers using the Hubble Space Telescope reports a significant brightening of the emissions from Supernova 1987A. The results, which appear in this week's Science magazine, are consistent with theoretical predictions about how supernovae interact with their immediate galactic environment.

The team observed the supernova remnant in optical, ultraviolet, and near-infrared light. They studied the interaction between the ejecta from the stellar explosion and a glowing 6-trillion-mile-diameter ring of gas encircling the supernova remnant. The gas ring was probably shed some 20,000 years before the supernova exploded. Shock waves resulting from the impact of the ejecta onto the ring have brightened 30 to 40 pearl-like "hot spots" in the ring. These blobs likely will grow and merge together in the coming years to form a continuous, glowing circle.

"We are seeing the effect a supernova can have in the surrounding galaxy, including how the energy deposited by these stellar explosions changes the dynamics and chemistry of the environment," said University of Colorado at Boulder Research Associate Kevin France of the Center for Astrophysics and Space Astronomy. "We can use these new data to understand how supernova processes regulate the evolution of galaxies."

Discovered in 1987, Supernova 1987A is the closest exploding star to Earth to be detected since 1604 and it resides in the nearby Large Magellanic Cloud, a dwarf galaxy adjacent to our own Milky Way Galaxy.

Source (with accompanying image).

-----

University of Colorado in Boulder: "New Hubble Observations of Supernova 1987A Reveal Composition of 'Star Guts' Pouring Out".

[Space Pete]

NASA's Hubble Harvests Distant Solar System Objects.

Beyond the orbit of Neptune reside countless icy rocks known as trans-Neptunian objects (TNOs). One of the biggest, Pluto, is classified as a dwarf planet. The region also supplies us with comets such as famous Comet Halley. Most TNOs are small and receive little sunlight, making them faint and difficult to spot.

Now, astronomers using clever techniques to cull the data archives of NASA's Hubble Space Telescope have added 14 new TNOs to the catalog. Their method promises to turn up hundreds more.

"Trans-Neptunian objects interest us because they are building blocks left over from the formation of the solar system," explained lead author Cesar Fuentes, formerly with the Harvard-Smithsonian Center for Astrophysics and now at Northern Arizona University.

As TNOs slowly orbit the sun, they move against the starry background, appearing as streaks of light in time exposure photographs. The team developed software to analyze hundreds of Hubble images hunting for such streaks. After promising candidates were flagged, the images were visually examined to confirm or refute each discovery.

Most TNOs are located near the ecliptic -- a line in the sky marking the plane of the solar system (since the solar system formed from a disk of material). Therefore, the team searched within 5 degrees of the ecliptic to increase their chance of success.

They found 14 objects, including one binary (two TNOs orbiting each other like a miniature Pluto-Charon system). All were very faint, with most measuring magnitude 25-27 (more than 100 million times fainter than objects visible to the unaided eye).

By measuring their motion across the sky, astronomers calculated an orbit and distance for each object. Combining the distance and brightness (plus an assumed albedo or reflectivity), they then estimated the size. The newfound TNOs range from 25 to 60 miles (40-100 km) across.

Unlike planets, which tend to have very flat orbits (known as low inclination), some TNOs have orbits significantly tilted from the ecliptic (high inclination). The team examined the size distribution of TNOs with low- versus high-inclination orbits to gain clues about how the population has evolved over the past 4.5 billion years.

Generally, smaller trans-Neptunian objects are the shattered remains of bigger TNOs. Over billions of years, these objects smack together, grinding each other down. The team found that the size distribution of TNOs with low- versus high-inclination orbits is about the same as objects get fainter and smaller. Therefore, both populations (low and high inclination) have similar collisional histories.

This initial study examined only one-third of a square degree of the sky, meaning that there is much more area to survey. Hundreds of additional TNOs may lurk in the Hubble archives at higher ecliptic latitudes. Fuentes and his colleagues intend to continue their search.

"We have proven our ability to detect and characterize TNOs even with data intended for completely different purposes," Fuentes said.

This research has been accepted for publication in The Astrophysical Journal and is available online.

The Hubble Space Telescope is a project of international cooperation between NASA and the European Space Agency. NASA’s Goddard Space Flight Center manages the telescope. The Space Telescope Science Institute (STScI) conducts Hubble science operations.
Headquartered in Cambridge, Mass., the Harvard-Smithsonian Center for Astrophysics (CfA) is a joint collaboration between the Smithsonian Astrophysical Observatory and the Harvard College Observatory. CfA scientists, organized into six research divisions, study the origin, evolution and ultimate fate of the universe.

Source.

[mike robel]

/quote
Generally, smaller trans-Neptunian objects are the shattered remains of bigger TNOs. Over billions of years, these objects smack together, grinding each other down. The team found that the size distribution of TNOs with low- versus high-inclination orbits is about the same as objects get fainter and smaller. Therefore, both populations (low and high inclination) have similar collisional histories.
quote/

Why do these object not accreat instead of shatter?  Are they now too cold to do so?  Can accreation only occur when the debris is molten?

[Space Pete]

Breaking Waves in the Stellar Lagoon.

A spectacular new NASA/ESA Hubble Space Telescope image reveals the heart of the Lagoon Nebula. Seen as a massive cloud of glowing dust and gas, bombarded by the energetic radiation of new stars, this placid name hides a dramatic reality.

The Advanced Camera for Surveys (ACS) on the NASA/ESA Hubble Space Telescope has captured a dramatic view of gas and dust sculpted by intense radiation from hot young stars deep in the heart of the Lagoon Nebula (Messier 8 ). This spectacular object is named after the wide, lagoon-shaped dust lane that crosses the glowing gas of the nebula.

This structure is prominent in wide-field images, but cannot be seen in this close-up. However the strange billowing shapes and sandy texture visible in this image make the Lagoon Nebula’s watery name eerily appropriate from this viewpoint too.

Located four to five thousand light-years away, in the constellation of Sagittarius (the Archer), Messier 8 is a huge region of star birth that stretches across one hundred light-years. Clouds of hydrogen gas are slowly collapsing to form new stars, whose bright ultraviolet rays then light up the surrounding gas in a distinctive shade of red.

The wispy tendrils and beach-like features of the nebula are not caused by the ebb and flow of tides, but rather by ultraviolet radiation’s ability to erode and disperse the gas and dust into the distinctive shapes that we see.

In recent years astronomers probing the secrets of the Lagoon Nebula have found the first unambiguous proof that star formation by accretion of matter from the gas cloud is ongoing in this region.

Young stars that are still surrounded by an accretion disc occasionally shoot out long tendrils of matter from their poles. Several examples of these jets, known as Herbig-Haro objects, have been found in this nebula in the last five years, providing strong support for astronomers’ theories about star formation in such hydrogen-rich regions.

The Lagoon Nebula is faintly visible to the naked eye on dark nights as a small patch of grey in the heart of the Milky Way. Without a telescope, the nebula looks underwhelming because human eyes are unable to distinguish clearly between colours at low light levels.

Charles Messier, the 18th century French astronomer, observed the nebula and included it in his famous astronomical catalogue, from which the nebula’s alternative name comes. But his relatively small refracting telescope would only have hinted at the dramatic structures and colours now visible thanks to Hubble.


www.spacetelescope.org/news/heic1015

[Space Pete]

Hubble Probes Comet 103P/Hartley 2 in Preparation for DIXI/EPOXI Flyby.

Hubble Space Telescope observations of comet 103P/Hartley 2, taken on September 25, are helping in the planning for a November 4 flyby of the comet by the Deep Impact eXtended Investigation (DIXI) on NASA's EPOXI spacecraft.

See the rest:
• See All the Images.


http://hubblesite.org/newscenter/archive/releases/2010/35

[jacqmans]

RELEASE: 10-243

HUBBLE ASTRONOMERS UNCOVER AN OVERHEATED EARLY UNIVERSE

WASHINGTON -- During a period of universal warming 11 billion years
ago, quasars -- the brilliant core of active galaxies -- produced
fierce radiation blasts that stunted the growth of some dwarf
galaxies for approximately 500 million years.

This important conclusion comes from a team of astronomers that used
the new capabilities of NASA's Hubble Space Telescope to probe the
invisible, remote universe. The team's results will be published in
the October 10 issue of The Astrophysical Journal.

Using Hubble's Cosmic Origins Spectrograph (COS), the astronomers
identified this era, from 11.7 to 11.3 billion years ago, when the
ultraviolet light emitted by active galaxies stripped electrons off
helium atoms. The process, known as ionization, heated the
intergalactic helium from 18,000 degrees Fahrenheit to nearly 40,000
degrees. This inhibited the gas from gravitationally collapsing to
form new generations of stars in some small galaxies.

Because of its greatly improved sensitivity and lower background
"noise" compared to previous spectrographs in space, the COS
observations were ground-breaking. The observations allowed
scientists to produce more detailed measurements of the intergalactic
helium than previously possible.

"These COS results yield new insight into an important phase in the
history of our universe," said Hubble Program Scientist Eric Smith at
NASA Headquarters in Washington.

Michael Shull of the University of Colorado in Boulder and his team
studied the spectrum of ultraviolet light produced by a quasar and
found signs of ionized helium. This beacon, like a headlight shining
through fog, travels through interspersed clouds of otherwise
invisible gas and allows for a core sample of the gas clouds.

The universe went through an initial heat wave more than 13 billion
years ago when energy from early massive stars ionized cold
interstellar hydrogen from the big bang. This epoch is called
reionization, because the hydrogen nuclei originally were in an
ionized state shortly after the big bang.

The Hubble team found it would take another two billion years before
the universe produced sources of ultraviolet radiation with enough
energy to reionize the primordial helium that also was cooked up in
the big bang. This radiation didn't come from stars, but rather from
super massive black holes. The black holes furiously converted some
of the gravitational energy of this mass to powerful ultraviolet
radiation that blazed out of these active galaxies.

The helium's reionization occurred at a transitional time in the
universe's history when galaxies collided to ignite quasars. After
the helium was reionized, intergalactic gas again cooled down and
dwarf galaxies could resume normal assembly.

"I imagine quite a few more dwarf galaxies may have formed if helium
reionization had not taken place," Shull said.

So far, Shull and his team only have one perspective to measure the
helium transition to its ionized state. However, the COS science team
plans to use Hubble to look in other directions to determine if
helium reionization uniformly took place across the universe.

For illustrations and more information about these results, visit:



http://hubblesite.org/news/2010/31

[jacqmans]

RELEASE: 10-254

NASA MISSION TO ASTEROID GETS HELP FROM HUBBLE SPACE TELESCOPE

WASHINGTON -- NASA's Hubble Space Telescope has captured images of the
large asteroid Vesta that will help scientists refine plans for the
Dawn spacecraft's rendezvous with Vesta in July 2011.

Scientists have constructed a video from the images that will help
improve pointing instructions for Dawn as it is placed in a polar
orbit around Vesta. Analyses of Hubble images revealed a pole
orientation, or tilt, of approximately four degrees more to the
asteroid's east than scientists previously thought.

This means the change of seasons between the southern and northern
hemispheres of Vesta may take place about a month later than
previously expected while Dawn is orbiting the asteroid. The result
is a change in the pattern of sunlight expected to illuminate the
asteroid. Dawn needs solar illumination for imaging and some mapping
activities.

"While Vesta is the brightest asteroid in the sky, its small size
makes it difficult to image from Earth," said Jian-Yang Li, a
scientist participating in the Dawn mission from the University of
Maryland in College Park. "The new Hubble images give Dawn scientists
a better sense of how Vesta is spinning because our new views are 90
degrees different from our previous images. It's like having a
street-level view and adding a view from an airplane overhead."

The recent images were obtained by Hubble's Wide Field Camera 3 in
February. The images complemented previous ones of Vesta taken from
ground-based telescopes and Hubble's Wide Field and Planetary Camera
2 between 1983 and 2007. Li and his colleagues looked at 216 new
images -- and a total of 446 Hubble images overall -- to clarify how
Vesta was spinning. The journal Icarus recently published the report
online.

"The new results give us food for thought as we make our way toward
Vesta," said Christopher Russell, Dawn's principal investigator at
the University of California, Los Angeles. "Because our goal is to
take pictures of the entire surface and measure the elevation of
features over most of the surface to an accuracy of about 33 feet, or
the height of a three-story building, we need to pay close attention
to the solar illumination. It looks as if Vesta is going to have a
late northern spring next year, or at least later than we planned."

Launched in September 2007, Dawn will leave Vesta to encounter the
dwarf planet Ceres in 2015. Vesta and Ceres are the most massive
objects in the main asteroid belt between Mars and Jupiter.
Scientists study these celestial bodies as examples of the building
blocks of terrestrial planets like Earth. Dawn is approximately 134
million miles away from Vesta. Next summer, the spacecraft will make
its own measurements of Vesta's rotating surface and allow mission
managers to pin down its axis of spin.

"Vesta was discovered just over 200 years ago, and we are excited now
to be on the threshold of exploring it from orbit," said Bob Mase,
Dawn's project manager at NASA's Jet Propulsion Laboratory (JPL) in
Pasadena, Calif. "We planned this mission to accommodate our
imprecise knowledge of Vesta. Ours is a journey of discovery and,
with our ability to adapt, we are looking forward to collecting
excellent science data at our target."

The Dawn mission is managed by JPL for NASA's Science Mission
Directorate at the agency's headquarters in Washington. Orbital
Sciences Corporation of Dulles, Va., designed and built the
spacecraft. Several international space organizations are part of the
mission team.

To see the Vesta images and video, visit:


http://www.nasa.gov/mission_pages/dawn/multimedia/vestavid20101008.html 

To learn more about Dawn and its mission to the asteroid belt, visit:


http://www.nasa.gov/dawn 

[jacqmans]

RELEASE: 10-253

NASA'S HUBBLE CAPTURES FIRST IMAGES OF AFTERMATH OF POSSIBLE ASTEROID COLLISION

WASHINGTON -- NASA's Hubble Space Telescope has captured the first
snapshots of a suspected asteroid collision. The images show a
bizarre X-shaped object at the head of a comet-like trail of
material.

In January, astronomers began using Hubble to track the object for
five months. They thought they had witnessed a fresh asteroid
collision, but were surprised to learn the collision occurred in
early 2009.

"We expected the debris field to expand dramatically, like shrapnel
flying from a hand grenade," said astronomer David Jewitt of the
University of California in Los Angeles, who is a leader of the
Hubble observations. "But what happened was quite the opposite. We
found that the object is expanding very, very slowly."

The peculiar object, dubbed P/2010 A2, was found cruising around the
asteroid belt, a reservoir of millions of rocky bodies between the
orbits of Mars and Jupiter. It is estimated modest-sized asteroids
smash into each other about once a year. When the objects collide,
they inject dust into interplanetary space. But until now,
astronomers have relied on models to make predictions about the
frequency of these collisions and the amount of dust produced.

Catching colliding asteroids is difficult because large impacts are
rare while small ones, such as the one that produced P/2010 A2, are
exceedingly faint. The two asteroids that make up P/2010 A2 were
unknown before the collision because they were too faint to be
noticed. The collision itself was unobservable because of the
asteroids' position in relation to the sun.

About 10 or 11 months later, in January 2010, the Lincoln Near-Earth
Research (LINEAR) Program Sky Survey spotted the comet-like tail
produced by the collision. But only Hubble discerned the X pattern,
offering unequivocal evidence that something stranger than a comet
outgassing had occurred.

Although the Hubble images give compelling evidence for an asteroid
collision, Jewitt says he still does not have enough information to
rule out other explanations for the peculiar object. In one such
scenario, a small asteroid's rotation increases from solar radiation
and loses mass, forming the comet-like tail.

"These observations are important because we need to know where the
dust in the solar system comes from, and how much of it comes from
colliding asteroids as opposed to 'outgassing' comets," Jewitt said.
"We also can apply this knowledge to the dusty debris disks around
other stars, because these are thought to be produced by collisions
between unseen bodies in the disks. Knowing how the dust was produced
will yield clues about those invisible bodies."

The Hubble images, taken from January to May 2010 with the telescope's
Wide Field Camera 3, reveal a point-like object about 400 feet wide,
with a long, flowing dust tail behind a never-before-seen X pattern.
Particle sizes in the tail are estimated to vary from about 1/25th of
an inch to an inch in diameter.

The 400-foot-wide object in the Hubble image is the remnant of a
slightly larger precursor body. Astronomers think a smaller rock,
perhaps 10 to 15 feet wide, slammed into the larger one. The pair
probably collided at high speed, about 11,000 mph, which smashed and
vaporized the small asteroid and stripped material from the larger
one. Jewitt estimates that the violent encounter happened in February
or March 2009 and was as powerful as the detonation of a small atomic
bomb.

Sunlight radiation then swept the debris behind the remnant asteroid,
forming a comet-like tail. The tail contains enough dust to make a
ball 65 feet wide, most of it blown out of the bigger body by the
impact-caused explosion. The science journal Nature will publish the
findings in the Oct. 14 issue.

"Once again, Hubble has revealed unexpected phenomena occurring in our
celestial 'back yard," said Eric Smith, Hubble Program scientist at
NASA Headquarters in Washington. "Though it's often Hubble's deep
observations of the universe or beautiful images of glowing nebulae
in our galaxy that make headlines, observations like this of objects
in our own solar system remind us how much exploration we still have
to do locally."

Astronomers do not have a good explanation for the X shape. The
crisscrossed filaments at the head of the tail suggest that the
colliding asteroids were not perfectly symmetrical. Material ejected
from the impact, therefore, did not make a symmetrical pattern, a bit
like the ragged splash made by throwing a rock into a lake. Larger
particles in the X disperse very slowly and give this structure its
longevity.

Astronomers plan to use Hubble again next year to view the object.
Jewitt and his colleagues hope to see how far the dust has been swept
back by the sun's radiation and how the mysterious X-shaped structure
has evolved.

For images, movies, and more information about asteroid encounter
P/2010 A2, visit:

http://hubblesite.org/news/2010/34   

and

http://www.nasa.gov/hubble   


-end-

[Space Pete]

Pinwheel of Star Birth.

This face-on spiral galaxy, called NGC 3982, is striking for its rich tapestry of star birth, along with its winding arms. The arms are lined with pink star-forming regions of glowing hydrogen, newborn blue star clusters, and obscuring dust lanes that provide the raw material for future generations of stars. The bright nucleus is home to an older population of stars, which grow ever more densely packed toward the center.

NGC 3982 is located about 68 million light-years away in the constellation Ursa Major. The galaxy spans about 30,000 light-years, one-third of the size of our Milky Way galaxy. This color image is composed of exposures taken by the Hubble Space Telescope's Wide Field Camera 3 (WFC3), the Advanced Camera for Surveys (ACS), and the Wide Field Planetary Camera 2 (WFPC2). The observations were taken between March 2000 and August 2009.


http://hubblesite.org/newscenter/archive/releases/2010/36

[jacqmans]

Hubble Zooms in on a Space Oddity

A ghostly, glowing, green blob of gas has become one of astronomy's great cosmic mystery stories. The space oddity was spied in 2007 by Dutch high-school teacher Hanny van Arkel while participating in the online Galaxy Zoo project. The cosmic blob, called Hanny's Voorwerp (Hanny's Object in Dutch), appears to be a solitary green island floating near a normal-looking spiral galaxy, called IC 2497. Since the discovery, puzzled astronomers have used a slew of telescopes, including X-ray and radio observatories, to help unwrap the mystery. Astronomers found that Hanny's Voorwerp is the only visible part of a 300-light-year-long gaseous streamer stretching around the galaxy. The greenish Voorwerp is visible because a searchlight beam of light from the galaxy's core illuminated it.

This beam came from a quasar, a bright, energetic object that is powered by a black hole. An encounter with another galaxy may have fed the black hole and pulled the gaseous streamer from IC 2497.

 
http://hubblesite.org/newscenter/archive/releases/2011/01/full/

http://hubblesite.org/newscenter/archive/releases/2011/01/image/

[ngc3314]

Hubble Zooms in on a Space Oddity

Grinning myself silly seeing that reposted here. I was the principal investigator for those HST observations; everything about the story from discovery to science results has been great. There's even a comic book (funded as a public-outreach activity by NASA).

[jacqmans]

MEDIA ADVISORY: M11-015

NASA ANNOUNCES MEDIA TELECONFERENCE ABOUT HUBBLE DISCOVERY

WASHINGTON -- NASA will hold a media teleconference at 1 p.m. EST on
Wednesday, Jan. 26. Astronomers have pushed the Hubble Space
Telescope to its limits and have seen further back in time than ever
before. The related discussion will focus on new research findings to
be published in the journal Nature.

The teleconference panelists are:

-- Rychard Bouwens, Hubble co-investigator, University of California,
Santa Cruz, and Leiden University, The Netherlands
-- Garth Illingworth, Hubble principal investigator, University of
California, Santa Cruz
-- Eric Smith, Hubble Space Telescope and James Webb Space Telescope
Program Scientist, NASA Headquarters, Washington

To participate, reporters must contact Trent Perrotto at
[email protected] or 202-358-0321, by 9 a.m. on Jan. 26 for
dial-in instructions.

Audio of the teleconference will be streamed live on NASA's website
at:

http://www.nasa.gov/newsaudio


For more information about Hubble, visit:

http://www.nasa.gov/hubble   

[jacqmans]

RELEASE: 11-025

NASA'S HUBBLE FINDS MOST DISTANT GALAXY CANDIDATE EVER SEEN IN UNIVERSE

WASHINGTON -- Astronomers have pushed NASA's Hubble Space Telescope to
its limits by finding what is likely to be the most distant object
ever seen in the universe. The object's light traveled 13.2 billion
years to reach Hubble, roughly 150 million years longer than the
previous record holder. The age of the universe is approximately 13.7
billion years.

The tiny, dim object is a compact galaxy of blue stars that existed
480 million years after the big bang. More than 100 such
mini-galaxies would be needed to make up our Milky Way. The new
research offers surprising evidence that the rate of star birth in
the early universe grew dramatically, increasing by about a factor of
10 from 480 million years to 650 million years after the big bang.

"NASA continues to reach for new heights, and this latest Hubble
discovery will deepen our understanding of the universe and benefit
generations to come," said NASA Administrator Charles Bolden, who was
the pilot of the space shuttle mission that carried Hubble to orbit.
"We could only dream when we launched Hubble more than 20 years ago
that it would have the ability to make these types of groundbreaking
discoveries and rewrite textbooks."

Astronomers don't know exactly when the first stars appeared in the
universe, but every step farther from Earth takes them deeper into
the early formative years when stars and galaxies began to emerge in
the aftermath of the big bang.

"These observations provide us with our best insights yet into the
earlier primeval objects that have yet to be found," said Rychard
Bouwens of the University of Leiden in the Netherlands. Bouwens and
Illingworth report the discovery in the Jan. 27 issue of the British
science journal Nature.

This observation was made with the Wide Field Camera 3 starting just a
few months after it was installed in the observatory in May 2009,
during the last NASA space shuttle servicing mission to Hubble. After
more than a year of detailed observations and analysis, the object
was positively identified in the camera's Hubble Ultra Deep
Field-Infrared data taken in the late summers of 2009 and 2010.

The object appears as a faint dot of starlight in the Hubble
exposures. It is too young and too small to have the familiar spiral
shape that is characteristic of galaxies in the local universe.
Although its individual stars can't be resolved by Hubble, the
evidence suggests this is a compact galaxy of hot stars formed more
than 100-to-200 million years earlier from gas trapped in a pocket of
dark matter.

"We're peering into an era where big changes are afoot," said Garth
Illingworth of the University of California at Santa Cruz. "The rapid
rate at which the star birth is changing tells us if we go a little
further back in time we're going to see even more dramatic changes,
closer to when the first galaxies were just starting to form."

The proto-galaxy is only visible at the farthest infrared wavelengths
observable by Hubble. Observations of earlier times, when the first
stars and galaxies were forming, will require Hubble's successor, the
James Webb Space Telescope (JWST).

The hypothesized hierarchical growth of galaxies -- from stellar
clumps to majestic spirals and ellipticals -- didn't become evident
until the Hubble deep field exposures. The first 500 million years of
the universe's existence, from a z of 1000 to 10, is the missing
chapter in the hierarchical growth of galaxies. It's not clear how
the universe assembled structure out of a darkening, cooling fireball
of the big bang. As with a developing embryo, astronomers know there
must have been an early period of rapid changes that would set the
initial conditions to make the universe of galaxies what it is today.


"After 20 years of opening our eyes to the universe around us, Hubble
continues to awe and surprise astronomers," said Jon Morse, NASA's
Astrophysics Division director at the agency's headquarters in
Washington. "It now offers a tantalizing look at the very edge of the
known universe -- a frontier NASA strives to explore."

Hubble is a project of international cooperation between NASA and the
European Space Agency. NASA's Goddard Space Flight Center in
Greenbelt, Md., manages the telescope. The Space Telescope Science
Institute (STScI) conducts Hubble science operations. STScI is
operated for NASA by the Association of Universities for Research in
Astronomy, Inc., in Washington.

For more information about Hubble, visit:



http://www.nasa.gov/hubble

[jacqmans]

RELEASE: 11-073

NASA'S HUBBLE RULES OUT ONE ALTERNATIVE TO DARK ENERGY



WASHINGTON -- Astronomers using NASA's Hubble Space Telescope have
ruled out an alternate theory on the nature of dark energy after
recalculating the expansion rate of the universe to unprecedented
accuracy.

The universe appears to be expanding at an increasing rate. Some
believe that is because the universe is filled with a dark energy
that works in the opposite way of gravity. One alternative to that
hypothesis is that an enormous bubble of relatively empty space eight
billion light-years across surrounds our galactic neighborhood. If we
lived near the center of this void, observations of galaxies being
pushed away from each other at accelerating speeds would be an
illusion.

This hypothesis has been invalidated because astronomers have refined
their understanding of the universe's present expansion rate. Adam
Riess of the Space Telescope Science Institute (STScI) and Johns
Hopkins University in Baltimore, Md., led the research. The Hubble
observations were conducted by the SHOES (Supernova Ho for the
Equation of State) team that works to refine the accuracy of the
Hubble constant to a precision that allows for a better
characterization of dark energy's behavior. The observations helped
determine a figure for the universe's current expansion rate to an
uncertainty of just 3.3 percent. The new measurement reduces the
error margin by 30 percent over Hubble's previous best measurement in
2009. Riess's results appear in the April 1 issue of The
Astrophysical Journal.

"We are using the new camera on Hubble like a policeman's radar gun to
catch the universe speeding," Riess said. "It looks more like it's
dark energy that's pressing the gas pedal."

Riess' team first had to determine accurate distances to galaxies near
and far from Earth. The team compared those distances with the speed
at which the galaxies are apparently receding because of the
expansion of space. They used those two values to calculate the
Hubble constant, the number that relates the speed at which a galaxy
appears to recede to its distance from the Milky Way. Because
astronomers cannot physically measure the distances to galaxies,
researchers had to find stars or other objects that serve as reliable
cosmic yardsticks. These are objects with an intrinsic brightness,
brightness that hasn't been dimmed by distance, an atmosphere, or
stellar dust, that is known. Their distances, therefore, can be
inferred by comparing their true brightness with their apparent
brightness as seen from Earth.

To calculate longer distances, Riess' team chose a special class of
exploding stars called Type 1a supernovae. These stellar explosions
all flare with similar luminosity and are brilliant enough to be seen
far across the universe. By comparing the apparent brightness of Type
1a supernovae and pulsating Cepheid stars, the astronomers could
measure accurately their intrinsic brightness and therefore calculate
distances to Type Ia supernovae in far-flung galaxies.

Using the sharpness of the new Wide Field Camera 3 (WFC3) to study
more stars in visible and near-infrared light, scientists eliminated
systematic errors introduced by comparing measurements from different
telescopes.

"WFC3 is the best camera ever flown on Hubble for making these
measurements, improving the precision of prior measurements in a
small fraction of the time it previously took," said Lucas Macri, a
collaborator on the SHOES Team from Texas A&M in College Station.

Knowing the precise value of the universe's expansion rate further
restricts the range of dark energy's strength and helps astronomers
tighten up their estimates of other cosmic properties, including the
universe's shape and its roster of neutrinos, or ghostly particles,
that filled the early universe.

"Thomas Edison once said 'every wrong attempt discarded is a step
forward,' and this principle still governs how scientists approach
the mysteries of the cosmos," said Jon Morse, astrophysics division
director at NASA Headquarters in Washington. "By falsifying the
bubble hypothesis of the accelerating expansion, NASA missions like
Hubble bring us closer to the ultimate goal of understanding this
remarkable property of our universe."

For images and more information about this study, visit:



http://www.nasa.gov/hubble

[jacqmans]

RELEASE: 11-119

NASA'S HUBBLE CELEBRATES 21ST ANNIVERSARY WITH "ROSE" OF GALAXIES

WASHINGTON -- To celebrate the 21st anniversary of the Hubble Space
Telescope's deployment into space, astronomers at the Space Telescope
Science Institute in Baltimore pointed Hubble's eye at an especially
photogenic pair of interacting galaxies called Arp 273. The new image
is available at:

http://www.nasa.gov/hubble

"For 21 years, Hubble has profoundly changed our view of the universe,
allowing us to see deep into the past while opening our eyes to the
majesty and wonders around us," NASA Administrator Charles Bolden
said."I was privileged to pilot space shuttle Discovery as it
deployed Hubble. After all this time, new Hubble images still inspire
awe and are a testament to the extraordinary work of the many people
behind the world's most famous observatory."

Hubble was launched April 24, 1990, aboard Discovery's STS-31 mission.
Hubble discoveries revolutionized nearly all areas of current
astronomical research from planetary science to cosmology.

"Hubble is America's gift to the world," Sen. Barbara Mikulski of
Maryland said. "Its jaw-dropping images have rewritten the textbooks
and inspired generations of schoolchildren to study math and science.
It has been documenting the history of our universe for 21 years.
Thanks to the daring of our brave astronauts, a successful servicing
mission in 2009 gave Hubble new life. I look forward to Hubble's
amazing images and inspiring discoveries for years to come."

The newly released Hubble image shows a large spiral galaxy, known as
UGC 1810, with a disk that is distorted into a rose-like shape by the
gravitational tidal pull of the companion galaxy below it, known as
UGC 1813. A swath of blue jewel-like points across the top is the
combined light from clusters of intensely bright and hot young blue
stars. These massive stars glow fiercely in ultraviolet light.

The smaller, nearly edge-on companion shows distinct signs of intense
star formation at its nucleus, perhaps triggered by the encounter
with the companion galaxy.

Arp 273 lies in the constellation Andromeda and is roughly 300 million
light-years away from Earth. The image shows a tenuous tidal bridge
of material between the two galaxies that are separated from each
other by tens of thousands of light-years.

A series of uncommon spiral patterns in the large galaxy are a
tell-tale sign of interaction. The large, outer arm appears partially
as a ring, a feature seen when interacting galaxies actually pass
through one another. This suggests the smaller companion dived deep,
but off-center, through UGC 1810. The inner set of spiral arms is
highly warped out of the plane, with one of the arms going behind the
bulge and coming back out the other side. How these two spiral
patterns connect is not precisely known.

The larger galaxy in the UGC 1810 - UGC 1813 pair has a mass about
five times that of the smaller galaxy. In unequal pairs such as this,
the relatively rapid passage of a companion galaxy produces the
lopsided or asymmetric structure in the main spiral. Also in such
encounters, the starburst activity typically begins in the minor
galaxies earlier than in the major galaxies. These effects could be
because the smaller galaxies have consumed less of the gas present in
their nuclei, from which new stars are born.

The interaction was imaged on Dec. 17, 2010, with Hubble's Wide Field
Camera 3 (WFC3). The picture is a composite of data taken with three
separate filters on WFC3 that allow a broad range of wavelengths
covering the ultraviolet, blue, and red portions of the spectrum.

The Hubble Space Telescope is a project of international cooperation
between NASA and the European Space Agency. NASA's Goddard Space
Flight Center manages the telescope. The Space Telescope Science
Institute (STScI) conducts Hubble science operations. STScI is
operated for NASA by the Association of Universities for Research in
Astronomy Inc. in Washington.

For image files and more information about Arp 273 and Hubble, visit:

http://www.nasa.gov/hubble   

and

http://hubblesite.org/news/2011/11

For the greatest hits of Hubble videos and images, visit:
http://www.nasa.gov/mission_pages/hubble/multimedia/index.html   

[jacqmans]

RELEASE: 11-162

NASA'S HUBBLE FINDS RARE 'BLUE STRAGGLER' STARS IN MILKY WAY'S HUB

WASHINGTON -- NASA's Hubble Space Telescope has found a rare class of
oddball stars called blue stragglers in the hub of our Milky Way, the
first detected within our galaxy's bulge.

Blue stragglers are so named because they seemingly lag behind in the
aging process, appearing younger than the population from which they
formed. While they have been detected in many distant star clusters,
and among nearby stars, they never have been seen inside the core of
our galaxy.

It is not clear how blue stragglers form. A common theory is that they
emerge from binary pairs. As the more massive star evolves and
expands, the smaller star gains material from its companion. This
stirs up hydrogen fuel and causes the growing star to undergo nuclear
fusion at a faster rate. It burns hotter and bluer, like a massive
young star.

The findings support the idea that the Milky Way's central bulge
stopped making stars billions of years ago. It now is home to aging
sun-like stars and cooler red dwarfs. Giant blue stars that once
lived there have long since exploded as supernovae. The results have
been accepted for publication in an upcoming issue of The
Astrophysical Journal. Lead author Will Clarkson of Indiana
University in Bloomington, will discuss them today at the American
Astronomical Society meeting in Boston.

"Although the Milky Way bulge is by far the closest galaxy bulge,
several key aspects of its formation and subsequent evolution remain
poorly understood," Clarkson said. "Many details of its
star-formation history remain controversial. The extent of the blue
straggler population detected provides two new constraints for models
of the star-formation history of the bulge."

The discovery followed a seven-day survey in 2006 called the
Sagittarius Window Eclipsing Extrasolar Planet Search (SWEEPS).
Hubble peered at 180,000 stars in the crowded central bulge of our
galaxy, 26,000 light-years away. The survey was intended to find hot
Jupiter-class planets that orbit very close to their stars. In doing
so, the SWEEPS team also uncovered 42 oddball blue stars with
brightness and temperatures typical for stars much younger than
ordinary bulge stars.

The observations clearly indicate that if there is a young star
population in the bulge, it is very small. It was not detected in the
SWEEPS program. Blue stragglers long have been suspected to be living
in the bulge, but had not been observed because younger stars in the
disk of our galaxy lie along the line-of-sight to the core, confusing
and contaminating the view.

Astronomers used Hubble to distinguish the motion of the core
population from foreground stars in the Milky Way. Bulge stars orbit
the galactic center at a different speed than foreground stars.
Plotting their motion required returning to the SWEEPS target region
with Hubble two years after the first observations were made. The
blue stragglers were identified as moving along with the other stars
in the bulge.
"The size of the field of view on the sky is roughly that of the
thickness of a human fingernail held at arm's length, and within this
region, Hubble sees about a quarter million stars toward the bulge,"
Clarkson said. "Only the superb image quality and stability of Hubble
allowed us to make this measurement in such a crowded field."

From the 42 candidate blue stragglers, the investigators estimate 18
to 37 are likely genuine. The remainder could be a mix of foreground
objects and, at most, a small population of genuinely young bulge
stars.

"The SWEEPS program was designed to detect transiting planets through
small light variations" said Kailash Sahu, the principal investigator
of the SWEEPS program. "Therefore the program could easily detect the
variability of binary pairs, which was crucial in confirming these
are indeed blue stragglers."

Hubble is a project of international cooperation between NASA and the
European Space Agency. NASA's Goddard Space Flight Center in
Greenbelt, Md., manages the telescope. The Space Telescope Science
Institute (STScI) conducts Hubble science operations. STScI is
operated for NASA by the Association of Universities for Research in
Astronomy in Washington. For images and more information about the
findings, visit:



http://www.nasa.gov/hubble

[jacqmans]

RELEASE: 11-217

NASA'S HUBBLE MAKES ONE MILLIONTH SCIENCE OBSERVATION

WASHINGTON -- NASA's Hubble Space Telescope crossed another milestone
in its space odyssey of exploration and discovery. On Monday, July 4,
the Earth-orbiting observatory logged its one millionth science
observation during a search for water in an exoplanet's atmosphere
1,000 light-years away.

"For 21 years Hubble has been the premier space science observatory,
astounding us with deeply beautiful imagery and enabling
ground-breaking science across a wide spectrum of astronomical
disciplines," said NASA Administrator Charles Bolden. He piloted the
space shuttle mission that carried Hubble to orbit. "The fact that
Hubble met this milestone while studying a faraway planet is a
remarkable reminder of its strength and legacy."

Although Hubble is best known for its stunning imagery of the cosmos,
the millionth observation is a spectroscopic measurement, where light
is divided into its component colors. These color patterns can reveal
the chemical composition of cosmic sources.

Hubble's millionth exposure is of the planet HAT-P-7b, a gas giant
planet larger than Jupiter orbiting a star hotter than our sun.
HAT-P-7b, also known as Kepler 2b, has been studied by NASA's
planet-hunting Kepler observatory after it was discovered by
ground-based observations. Hubble now is being used to analyze the
chemical composition of the planet's atmosphere.

"We are looking for the spectral signature of water vapor. This is an
extremely precise observation and it will take months of analysis
before we have an answer," said Drake Deming of the University of
Maryland and NASA's Goddard Space Flight Center in Greenbelt, Md.
"Hubble demonstrated it is ideally suited for characterizing the
atmospheres of exoplanets, and we are excited to see what this latest
targeted world will reveal."

Hubble was launched April 24, 1990, aboard space shuttle's Discovery's
STS-31 mission. Its discoveries revolutionized nearly all areas of
astronomical research from planetary science to cosmology. The
observatory has collected more than 50 terabytes of data to-date. The
archive of that data is available to scientists and the public at:


http://hla.stsci.edu/


Hubble's odometer reading includes every observation of astronomical
targets since its launch and observations used to calibrate its suite
of instruments. Hubble made the millionth observation using its Wide
Field Camera 3, a visible and infrared light imager with an on-board
spectrometer. It was installed by astronauts during the Hubble
Servicing Mission 4 in May 2009.

"The Hubble keeps amazing us with groundbreaking science," said Sen.
Barbara A. Mikulski, the chairwoman of the Senate Commerce, Justice,
Science and Related Agencies Appropriations Subcommittee that funds
NASA. "I championed the mission to repair and renew Hubble not just
to get one million science observations, but also to inspire millions
of children across the planet to become our next generation of
stargazers, scientists, astronauts and engineers."

Hubble is a project of international cooperation between NASA and the
European Space Agency. Goddard manages the telescope. The Space
Telescope Science Institute (STScI) conducts Hubble science
operations. STScI is operated for NASA by the Association of
Universities for Research in Astronomy Inc. in Washington.

For more information about Hubble, galleries of videos and images,
visit:


http://www.nasa.gov/hubble