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Space News Update — March 10, 2015 —
Contents
In the News
Story 1:
Comet Flyby: OSIRIS Catches Glimpse of Rosetta’s Shadow
Story 2:
NASA’s Hubble Discovers Four Images of Same Supernova Split by Cosmic Lens
Story 3:
Use of Rover Arm Expected to Resume in a Few Days
Departments
The Night Sky
ISS Sighting Opportunities
NASA-TV Highlights
Space Calendar
Food for Thought
Space Image of the Week
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1. Comet Flyby: OSIRIS Catches Glimpse of Rosetta’s Shadow
Close-up view of an area on the Imhotep region on Comet 67P/Churyumov-Gerasimenko, as seen by the OSIRIS Narrow
Angle Camera during Rosetta’s flyby at 12:39 UT on 14 February 2015. The image was taken six kilometers above the
comet’s surface, and the image resolution is just 11 cm/pixel. Rosetta’s fuzzy shadow, measuring approximately 20 x 50
meters, is seen at the bottom of the image. Credits: ESA/Rosetta/MPS for OSIRIS Team
MPS/UPD/LAM/IAA/SSO/INTA/UPM/DASP/IDA
Images from the OSIRIS scientific imaging camera taken during the close flyby on February 14 have now been
downlinked to Earth, revealing the surface of Comet 67P/C-G in unprecedented detail, and including the
shadow of the spacecraft encircled in a wreath of light.
The image released March 3rd shows an area near the edge of the comet’s “belly” close to the Imhotep-Ash
regional boundary, where a mesh of steep slopes separates smooth-looking terrains from a craggier area. The
image was taken from a distance of 6 km from the comet’s surface and has a resolution of 11 cm/pixel. It
covers an area of 228 x 228 m.
Indeed, while the match on the smooth-looking region at the bottom of the NAC image in the displayed
orientation is good, it is harder to match the upper half because of the lack of shadows in the NAC image, and
because the geometry/viewing perspective has changed between the images. This means that the NAC image
would have to be distorted and "draped" over the surface to fit the NAVCAM properly.
During the flyby, Rosetta not only passed closer by the comet than ever before, but also passed through a
unique observational geometry: for a short time the Sun, spacecraft, and comet were exactly aligned. In this
geometry, surface structures cast almost no shadows, and therefore the reflection properties of the surface
material can be discerned.
“Images taken from this viewpoint are of high scientific value,” says OSIRIS Principal Investigator Holger
Sierks from the Max Planck Institute for Solar System Research (MPS) in Germany. “This kind of view is key for
the study of grain sizes.”
As a side effect of this exceptional observational geometry, Rosetta’s shadow can be seen cast on the surface
of Comet 67P/C-G as a fuzzy rectangular-shaped dark spot surrounded by a bright halo-like region.
The shadow is fuzzy and somewhat larger than Rosetta itself, measuring approximately 20 x 50 meters. If the
Sun were a point source, the shadow would be sharp and almost exactly the same size as Rosetta
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(approximately 2 x 32 m). However, even at 347 million km from 67P/C-G on 14 February, the Sun appeared
as a disc about 0.2 degrees across (about 2.3 times smaller than on Earth), resulting in a fuzzy “penumbra”
around the spacecraft’s shadow on the surface. In this scenario and with Rosetta 6 km above the surface, the
penumbra effect adds roughly 20 meters to the spacecraft’s dimensions, and which is cast onto the tilted
surface of the comet.
If you were standing on the surface with Rosetta high above you, there would be no place in the shadow
where the entire Sun would be blocked from view, which explains why there is no fully dark core to the
shadow.
Rosetta is not the first spacecraft to capture its own shadow in this way. In 2005, JAXA’s Hayabusa spacecraft
captured its shadow on asteroid Itokawa. However, because Hayabusa was only a few tens of meters above
the surface, the penumbral effect was much less, resulting in a sharper and darker shadow of the spacecraft.
Also, the comet surface surrounding Rosetta’s shadow on Comet 67P/C-G appears significantly brighter than
the rest of the surface seen in the image. Scientists refer to this effect as the ‘opposition surge’ and it is
commonly observed when highly-structured regolith surfaces on planets and moons are illuminated directly
behind the observer. For example, astronauts on the lunar surface saw the effect surrounding their own
shadows. The primary cause of opposition surge is ‘shadow hiding’. When the Sun is directly behind the
observer, the shadows cast by small grains disappear from the perspective of the observer, hidden behind the
grains themselves, leading to a pronounced increase in brightness. There may also be a contribution from
coherent backscatter due to the retro-reflective properties of small dust grains.
Source: ESA Rosetta Blog Return to Contents
Graphic to illustrate the difference between how a sharp shadow is generated by a point source (left) and a fuzzy shadow by a diffuse source (right). Credits: Spacecraft: ESA/ATG medialab. Comet background: ESA/Rosetta/NAVCAM – CC BY-SA IGO 3.0
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2. NASA’s Hubble Discovers Four Images of Same Supernova Split by Cosmic
Lens
The image shows the galaxy's location within a hefty cluster of galaxies called MACS J1149.6+2223. Arrows (inset) point
to the multiple copies of Supernova Refsdal. The four images were spotted on Nov. 11, 2014. Image
Credit: NASA/ESA/STScI/UCLA
Astronomers using NASA’s Hubble Space Telescope have spotted for the first time a distant supernova split
into four images. The multiple images of the exploding star are caused by the powerful gravity of a foreground
elliptical galaxy embedded in a massive cluster of galaxies. This unique observation will help astronomers
refine their estimates of the mass of dark matter in the lensing galaxy and cluster. Dark matter is an invisible
form of matter that makes up most of the mass of the universe.
The gravity from both the elliptical galaxy and its galaxy cluster distorts and magnifies the light from the
supernova behind it in an effect called gravitational lensing. First predicted by Albert Einstein, this effect is
similar to a glass lens bending light to magnify and distort the image of an object behind it. The multiple
images are arranged around the elliptical galaxy in a cross-shaped pattern, also known an Einstein Cross.
The elliptical galaxy and its galaxy cluster, MACS J1149.6+2223, are 5 billion light-years away from Earth. The
supernova behind it is 9.3 billion light-years away.
Although astronomers have discovered dozens of multiply-imaged galaxies and quasars, they have never seen
a stellar explosion resolved into several images.
“It really threw me for a loop when I spotted the four images surrounding the galaxy— it was a complete
surprise,” said Patrick Kelly of the University of California, Berkeley, a member of the Grism Lens Amplified
Survey from Space (GLASS) collaboration. Kelly is also the lead author on the paper, which will appear on
March 6 in a special issue of the journal Science celebrating the centenary of Albert Einstein’s Theory of
General Relativity.
When the four images fade away, astronomers predict they will have the rare opportunity to see the
supernova again. This is because the current four-image pattern is only one component of the lensing display.
The supernova may have appeared as a single image some 20 years ago elsewhere in the cluster field, and it
is expected to reappear once more in about a decade.
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This prediction is based on computer models of the cluster, which describe the various paths the divided
supernova light is taking through the maze of clumpy dark matter in the galactic grouping. Each image takes a
different route through the cluster and arrives at a different time, due in part to differences in the length of
the pathways the light follows to reach Earth. The four supernova images captured by Hubble, for example,
appeared within a few days or weeks of each other.
The supernova’s various light paths are analogous to several trains that leave a station at the same time, all
traveling at the same speed and bound for the same location. Each train, however, takes a different route, and
the distance for each route is not the same. Some trains travel over hills. Others go through valleys, and still
others chug around mountains. Because the trains travel over different track lengths across different terrain,
they do not arrive at their destination at the same time. Similarly, the supernova images do not appear at the
same time because some of the light is delayed by traveling around bends created by the gravity of dense
dark matter in the intervening galaxy cluster.
“Our model for the dark matter in the cluster gives us the prediction of when the next image will appear
because it tells us how long each train track is, which correlates with time,” said Steve Rodney of the Johns
Hopkins University in Baltimore, Maryland, leader of the Frontier Field Supernova Search team (FrontierSN
team) that is working with the GLASS group to analyze the exploding star. “We already missed one that we
think appeared about 20 years ago and we found these four images after they had already appeared. The
prediction of this future image is the one that is most exciting because we might be able to catch it. We hope
to come back to this field with Hubble, and we’ll keep looking to see when that expected next image appears.”
Measuring the time delays between images offers clues to the type of warped-space terrain the supernova’s
light had to cover and will help the astronomers fine-tune the models that map out the cluster’s mass. “We will
measure the time delays, and we’ll go back and compare to the model predictions of the light path," Kelly said.
“The lens modelers, such as Adi Zitrin of the California Institute of Technology from our team, will then be
able to adjust their models to more accurately recreate the landscape of dark matter, which dictates the light
travel time.”
While making a routine search of the GLASS team’s data, Kelly spotted the four images of the exploding star
on Nov. 11, 2014. The FrontierSN and GLASS teams have been searching for such highly magnified explosions
since 2013, and this object is their most spectacular discovery. The supernova appears about 20 times brighter
than its natural brightness, due to the combined effects of two overlapping lenses. The dominant lensing
effect is from the massive galaxy cluster, which focuses the supernova light along at least three separate
paths. A secondary lensing effect occurs when one of those light paths is precisely aligned with a specific
elliptical galaxy within the cluster.
“The dark matter of that individual galaxy then bends and refocuses the light into four more paths,” Rodney
explained, “generating the rare Einstein Cross pattern we are currently observing.”
The two teams spent a week analyzing the object’s light, confirming it was the signature of a supernova. They
then turned to the W.M. Keck Observatory on Mauna Kea, in Hawaii, to measure the distance of the
supernova’s host galaxy.
The astronomers nicknamed the supernova Refsdal in honor of Norwegian astronomer Sjur Refsdal, who, in
1964, first proposed using time-delayed images from a lensed supernova to study the expansion of the
universe. “Astronomers have been looking to find one ever since,” said Tommaso Treu of the University of
California, Los Angeles, the GLASS project’s principal investigator. “The long wait is over!”
The Frontier Fields survey is a three-year program that uses Hubble and the gravitational-lensing effects of six
massive galaxy clusters to probe not only what is inside the clusters but also what is beyond them.
Source: NASA Return to Contents
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3. Use of Rover Arm Expected to Resume in a Few Days
This March 4, 2015, image from the Navcam on NASA's Curiosity Mars rover shows the position in which the rover held its
arm for several days after a transient short circuit triggered onboard fault-protection programming to halt arm activities
on Feb. 27. Image Credit: NASA/JPL-Caltech/MSSS
Managers of NASA's Curiosity Mars rover mission expect to approve resumption of rover arm movements as
early as next week while continuing analysis of what appears to be an intermittent short circuit in the drill.
A fluctuation in current on Feb. 27 triggered a fault-protection response that immediately halted action by the
rover during the mission's 911th Martian day, or sol. Since then, the rover team has avoided driving Curiosity
or moving the rover's arm, while engineers have focused on diagnostic tests. Science observations with
instruments on the rover's mast have continued, along with environmental monitoring by its weather station.
"Diagnostic testing this week has been productive in narrowing the possible sources of the transient short
circuit," said Curiosity Project Manager Jim Erickson of NASA's Jet Propulsion Laboratory, Pasadena, California.
"The most likely cause is an intermittent short in the percussion mechanism of the drill. After further analysis
to confirm that diagnosis, we will be analyzing how to adjust for that in future drilling."
The sample-collection drill on Curiosity's robotic arm uses both rotation and hammering, or percussion, to
penetrate into Martian rocks and collect pulverized rock material for delivery to analytical instruments inside
the rover.
The short on Sol 911 occurred while the rover was transferring rock-powder sample from the grooves of the
drill into a mechanism that sieves and portions the powder. The percussion action was in use, to shake the
powder loose from the drill.
Engineers received results Thursday, March 5, from a test on Curiosity that similarly used the drill's percussion
action. During the third out of 180 up-and-down repeats of the action, an apparent short circuit occurred for
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less than one one-hundredth of a second. Though small and fleeting, it would have been enough to trigger
the fault protection that was active on Sol 911 under the parameters that were in place then.
The rover team plans further testing to characterize the intermittent short before the arm is moved from its
present position, in case the short does not appear when the orientation is different.
After those tests, the team expects to finish processing the sample powder that the arm currently holds and
then to deliver portions of the sample to onboard laboratory instruments. Next, Curiosity will resume climbing
Mount Sharp.
Source: NASA
Opportunity Rover Examining Odd Mars Rocks at Valley Overlook & Reaches Marathon Distance
This map updates progress that NASA's Mars Exploration Rover Opportunity is making toward reaching a driving distance
equivalent to a marathon footrace. It indicates the rover position on March 5, 2015, relative to where it could surpass that distance. As of March 5, Opportunity has driven 26.139 miles (42.067 kilometers) since it landed on Mars in January
2004. This brings it within 140 yards (128 meters) of reaching the distance of a marathon footrace. Image Credit:
NASA/JPL-Caltech/Univ. of Arizona
Source: NASA Return to Contents
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The Night Sky
Source: Sky and Telescope Return to Contents
Tuesday, March 10
Jupiter this month forms a big, more-or-
less equilateral triangle with Procyon and
Pollux. Face southeast soon after dark, and
Procyon is to Jupiter's right. Pollux is high
above them.
Procyon is also part of the slightly larger
Winter Triangle just to the west, also
equilateral. Its other stars are orange
Betelgeuse and bright Sirius below.
Wednesday, March 11
The eclipsing variable star Algol should be
at minimum brightness, magnitude 3.4
instead of its usual 2.1, for a couple hours
tonight centered on midnight EDT; 9 p.m.
PDT. Algol takes several additional hours to
fade and to rebrighten.
Early risers will find the last-quarter Moon
passing over Saturn and Scorpius. They're
due south in early dawn. (See picture)
Before and during dawn Thursday morning
the 12th, the waning Moon poses near
Saturn, as shown here. Look for Antares
below them.
Thursday, March 12
On Friday morning the 13th, the last-quarter Moon shines to the left of Saturn and the head of Scorpius
before and during dawn.
Friday, March 13
You know the season is shifting. As the stars come out, the Big Dipper standing on its handle in the
northeast is now as high as Cassiopeia standing on end in the northwest. The Dipper is rising into spring and
summer, and Cassiopeia is descending from its high showing in fall and winter.
Saturday, March 14
On the traditional divide between the winter and spring sky is dim Cancer, marked this year by Jupiter.
Wintry Gemini is to its west, and Leo of spring is to its east. Don't be too distracted by Jupiter; Cancer also
hosts the Beehive Star Cluster, M44, in its middle. Look for it 6° to Jupiter's upper right after dark. That's
about the width of a binocular's field of view.
Algol should be in mid-eclipse around 9 p.m. Eastern Daylight Time.
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ISS Sighting Opportunities (from Denver)
Sighting information for other cities can be found at NASA’s Satellite Sighting Information
NASA-TV Highlights (all times Eastern Time Zone)
Tuesday, March 10
1 p.m. - NASA Magnetospheric Multiscale (MMS) Mission Prelaunch News Conference (all channels)
3 p.m. - NASA Social -- SLS Booster Test (all channels)
Wednesday, March 11
10:30 a.m. - Space Station Live (all channels)
11 a.m. - Live Coverage of the Orbital ATK Booster Test in Promontory, (all channels)
1 p.m. - NASA Magnetospheric Multiscale (MMS) Mission Science Briefing (all channels)
3 p.m. - ISS Expedition 42 Farewells and Hatch Closure Coverage (all channels)
6:15 p.m. - ISS Expedition 42/Soyuz TMA-14M Undocking Coverage (all channels)
9 p.m. - ISS Expedition 42/Soyuz TMA-14M Deorbit Burn and Landing Coverage (all channels)
Thursday, March 12
Midnight – Video File of the ISS Expedition 42/Soyuz TMA-14M Landing and Post-Landing Activities (all channels)
10:30 a.m. - Video File of the ISS Expedition 42/Soyuz TMA-14M Landing and Post-Landing Activities (Including an interview with
Expedition 42 Commander Barry Wilmore of NASA and the return of Expedition 42 Flight Engineers Alexander Samokutyaev and
Elena Serova (all channels)
3 p.m. - NASA Magnetospheric Multiscale (MMS) Mission Social (all channels)
8 p.m. - Live Launch coverage of NASA Magnetospheric Multiscale (MMS) Mission (Launch scheduled at 10:44 p.m. ET) (NTV-1
(Public), NTV-3 (Media))
9:15 p.m. - Live NASA Edge coverage of the launch of the Magnetospheric Multiscale (MMS) Mission from Kennedy Space Center,
Florida (NTV-2 (Education))
Watch NASA TV online by going to the NASA website. Return to Contents
Date Visible Max Height Appears Disappears
Wed Mar 11, 5:51 AM 3 min 31° 17 above S 27 above ESE
Thu Mar 12, 5:01 AM 1 min 15° 15 above ESE 11 above E
Thu Mar 12, 6:34 AM 6 min 50° 12 above WSW 11 above NE
Fri Mar 13, 5:43 AM 2 min 80° 63 above SSW 22 above NE
Sat Mar 14, 4:52 AM < 1 min 19° 19 above ENE 19 above ENE
Sat Mar 14, 6:25 AM 4 min 25° 15 above WNW 11 above NNE
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Space Calendar
Mar 10 - New Horizons Trajectory Correction Maneuver
Mar 10 - Comet C/2015 A1 (PANSTARRS) Perihelion (2.020 AU)
Mar 10 - Asteroid 12524 Conscience Closest Approach To Earth (1.770 AU)
Mar 11 - Mars Passes 0.3 Degrees from Uranus
Mar 11 - Comet C/2014 W6 (Catalina) At Opposition (2.206 AU)
Mar 11 - Asteroid 9025 Polansky Closest Approach To Earth (2.629 AU)
Mar 11 - 50th Anniversary (1965), Pioneer 5 Launch (Solar Orbiter)
Mar 11 - Nicolas Bloembergen's 95th Birthday (1920)
Mar 12 - Soyuz TMA Return To Earth (International Space Station)
Mar 12 - Magnetospheric Multiscale (MMS 1-4) Atlas 5 Launch
Mar 12 - Kompsat 3A Dnepr 1 Launch
Mar 12 - Comet C/2013 V5 (Oukaimeden) Closest Approach To Earth (2.125 AU)
Mar 12 - Comet C/2013 V2 (Borisov) Closest Approach To Earth (2.960 AU)
Mar 12 - Comet C/2015 D3 (PANSTARRS) At Opposition (7.568 AU)
Mar 12 - Asteroid 498 Tokio Occults HIP 14439 (5.6 Magnitude Star)
Mar 12 - Asteroid 78577 JPL Closest Approach To Earth (1.956 AU)
Mar 12 - Simon Newcomb's 180th Birthday (1835)
Mar 13 - Cassini, Orbital Trim Maneuver #406 (OTM-406)
Mar 13 - Comet C/2014 W6 (Catalina) Closest Approach To Earth (2.206 AU)
Mar 13 - Comet 6P/d'Arrest Closest Approach To Earth (2.297 AU)
Mar 13 - Comet C/2014 N3 (NEOWISE) Perihelion (3.882 AU)
Mar 13 - Asteroid 141527 (2002 FG7) Near-Earth Flyby (0.044 AU)
Mar 13 - Asteroid 12426 Racquetball Closest Approach To Earth (1.484 AU)
Mar 13 - Asteroid 2688 Halley Closest Approach To Earth (2.316 AU)
Mar 13 - 35th Anniversary (1980), Pascu/Seidelmann/Baum/Currie's Discovery of Saturn Moon Calypso
Mar 13 - Percival Lowell's 160th Birthday (1855)
Mar 14 - Cassini, Distant Flyby of Helene & Calypso
Mar 14 - Comet 295P/LINEAR At Opposition (2.331 AU)
Mar 14 - Asteroid 3199 Nefertiti Closest Approach To Earth (0.990 AU)
Mar 14 - Heidi Hammel's 55th Birthday (1960)
Mar 14 - Giovanni Schiaparelli's 180th Birthday (1835)
Source: JPL Space Calendar Return to Contents
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Food for Thought
Fastest Star in the Galaxy Has a Strange Origin
An astrophysicist-artist's conception of a hypervelocity star speeding away from the visible part of a spiral galaxy like our
Milky Way. Hypervelocity star 708 is now the fastest-recorded star on its way out of the galaxy, and its origin story is
highly unique. Credit: Ben Bromley, University of Utah
The fastest-known star in the Milky Way is on a path out of the galaxy, and new research suggests it was a
supernova that gave it the boot.
The runaway star, US 708, is traveling at 7,456 miles per second (12,000 km/s) — that's 26 million miles per hour
(43 million km/h) —making it the fastest star in the Milky Way ever clocked by astronomers, according to the new
research. Its speed will allow it to escape the gravitational pull of the galaxy, and eventually make its way into
intergalactic space. A NASA animation shows the hypervelocity star's ejection after a star explosion, kicking off the
rogue flight across the Milky Way.
Most other stars moving fast enough to get out of the galaxy are thought to be ejected by the monster black hole
at the galactic center, the researchers say. US 708 is the first star with a different origin story, and the new
research suggests its life has been strange and chaotic.
Outta Here!
Our sun and most of the millions of stars in the Milky Way collectively orbit the center of the galaxy at a mild pace:
Our sun travels about 125 miles per second, or 450,000 miles per hour.
But there is a class of so-called hypervelocity stars, or HVSs, that are moving with speeds high enough to escape
the gravitational pull of the galaxy. Thus far, the fastest of these hypervelocity stars have been clocked at about 2
million miles per hour. But US 708 is moving at more than 26 million miles per hour.
"It's significantly faster," said Stephan Geier, a postdoctoral researcher at the European Southern Observatory and
co-author on the new research.
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Geier and some colleagues first identified UB 708 in 2005. In the new work, he and his co-authors were able to
measure the speed of the star by using both current and archival data, and watching its motion change over a total
of about 70 years.
The monster black hole at the center of the Milky Way has the gravitational muscle to fling a star on a one-way-
track out of the neighborhood, and many other hypervelocity stars are thought to originate from there. But US 708
didn't start its journey near the galactic center, the new research shows.
Based on additional clues, the scientists say it was probably orbiting another star when its path changed. US 708
and its partner star were likely orbiting each other very quickly, with a very small distance between them. The
neighbor star exploded into a supernova and was completely destroyed. US 708 was suddenly without a
gravitational tether to keep it in the same place, and all that rotational speed and energy then abruptly started
moving in a straight line.
"It's like if you are riding a swing carousel, where you are connected with a chain, and you cut the chain — then
you fly away from the carousel," Geier said. "In this case the carousel explodes."
An uncommon life for a star
The researchers can't look back in time to see what happened to US 708 before it was set on its current course. But
the clues they need are in the star's physical characteristics and current behavior.
Speed isn't the only thing that sets US 708 apart from other hypervelocity stars. Before 2014, all detected HVSs
were main sequence stars, similar to our sun. Early that year, a group of much larger hypervelocity stars was
discovered (those stars also appear to have originated away from the galactic center). But US 708 is not main
sequence, and it is not large; it's what's known as a hot sub-dwarf.
As their name suggests, hot sub-dwarfs are small but have very high temperatures suggesting they were once
much more massive. US 708 is currently about half the mass of our sun, but the researchers say it was likely a red
giant earlier in its lifetime, with a mass two to three times that of our sun. The red giant's outer layers of hydrogen
were probably siphoned off by another nearby star, leaving behind a smaller sub-dwarf star made mostly of helium.
This cannibalizing neighbor star was most likely a white dwarf: a collapsed star that is no longer burning fuel. After
it ate the outer layers of hydrogen from US 708, it then began sucking helium away from US 708, which is what
eventually led to its demise.
Helium is a highly combustible gas, and as the white dwarf gobbled up more of this material, steadily creating a
thick, hot layer on its surface, the helium ignited. Theories suggest that this buildup and ignition of helium then
kick-starts the burning of carbon inside the star, which can then trigger the destruction of the entire star, as in a
Type 1a supernova explosion. "The white dwarf was completely destroyed," Geier said.
Once again, the removal of the white dwarf set US 708 on a path out of the galaxy. The explosion itself most likely
contributed very little energy to the star as it left the system, he said.
"It's probably one of the most dramatic life stories of a star," Geier said. "The star went through a lot."
The researchers can't say for sure if US 708 came from a region where a Type 1a supernova went off. The
remnants of such an event would be long gone, Geier said. But the physical characteristics of the star led them to
this conclusion: the fact that US 708 is a hot sub-dwarf made mostly of helium, and the fact that it is rotating very
rapidly (this would be a product of its close orbit with the white dwarf).
Geier and his colleagues say studying more stars like US 708 could provide information about how Type 1a
supernovas form. Scientists use these bright points of light to measure large distances in the universe, so
understanding them better can influence many areas of astronomy.
Source: Space.com Return to Contents
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Space Image of the Week
Pillars and Jets in the Pelican Nebula Image Credit & Copyright: Larry Van Vleet (LVVASTRO)
Explanation: What dark structures arise from the Pelican Nebula? Visible as a bird-shaped nebula toward the
constellation of a bird (Cygnus, the Swan), the Pelican Nebula is a place dotted with newly formed stars but
fouled with dark dust. These smoke-sized dust grains formed in the cool atmospheres of young stars and were
dispersed by stellar winds and explosions. Impressive Herbig-Haro jets are seen emitted by a star on the right
that is helping to destroy the light year-long dust pillar that contains it. The featured image was scientifically-
colored to emphasize light emitted by small amounts of ionized nitrogen, oxygen, and sulfur in the nebula
made predominantly of hydrogen and helium. The Pelican Nebula (IC 5067 and IC 5070) is about 2,000 light-
years away and can be found with a small telescope to the northeast of the bright star Deneb.
Source: NASA APOD Return to Contents