Posted on by Tammy Plotner

PacMan Nebula Takes A “Bite” Out Of Space

n visible light, the star-forming cloud catalogued as NGC 281 in the constellation of Cassiopeia appears to be chomping through the cosmos, earning it the nickname the "Pacman" nebula after the famous Pac-Man video game of the 1980s. Image Credit: NASA/JPL-Caltech/UCLA

[/caption]

If you have a large telescope and an appetite for nebulae, then you’ve probably seen the Pac Man Nebula. Located 9,200 light years away in the constellation Cassiopeia, NGC 281 (RA 00 52 59.3 – Dec +56 37 19) is a seasonal favorite… and in this new image it’s showing a real “Halloween” face!

Discovered in August 1883 by E. E. Barnard, this diffuse HII region is home to open cluster IC 1590, the multiple star HD 5005, and several Bok globules. To the eye of the amateur telescope, it’s a soft, round region with a distinctive notch that makes it resemble the PacMan of video game fame. However, when seen in infrared light by NASA’s Wide-field Infrared Survey Explorer, or WISE, the PacMan appears to have “teeth”!

Of course, astronomers know these fanciful fangs are actually pillars where new stars are forming. They are created when stellar winds and radiation from the accompanying cluster blow away the gas and dust, revealing the dense star dough. If you see small red sprinkles in this cosmic cookie, then you’re looking at what could be very young stars in the process of springing to life.

According to JPL News, this image was made from observations by all four infrared detectors aboard WISE. Blue and cyan (blue-green) represent infrared light at wavelengths of 3.4 and 4.6 microns, respectively, which is primarily from stars, the hottest objects pictured. Green and red represent light at 12 and 22 microns, respectively, which is primarily from warm dust (with the green dust being warmer than the red dust).

It’s a great trick… or “treat”!

Original Story Source: JPL News.

Posted on by Nancy Atkinson

Space Telescopes Provide New Look at 2,000 Year Old Supernova

This image combines data from four different space telescopes to create a multi-wavelength view of all that remains of the oldest documented example of a supernova, called RCW 86.

[/caption]

What caused a huge explosion nearly 2,000 years ago, seen by early Chinese astronomers? Scientists have long known that a “guest star” that had mysteriously appeared in the sky and stayed for about 8 months in the year 185 was the first documented supernova. But now the combined efforts of four space observatories have provided insight into this stellar explosion and why it was so huge – and why its shattered remains — the object known as RCW 86 – is now spread out to great distances.

“This supernova remnant got really big, really fast,” said Brian Williams, an astronomer at North Carolina State University in Raleigh. “It’s two to three times bigger than we would expect for a supernova that was witnessed exploding nearly 2,000 years ago. Now, we’ve been able to finally pinpoint the cause.”

By studying new infrared observations from the Spitzer Space Telescope and data from the Wide-field Infrared Survey Explorer, and previous data from NASA’s Chandra X-ray Observatory and the European Space Agency’s XMM-Newton Observatory, astronomers were able to determine that the ancient supernova was a Type Ia supernova. And doing some “forensics” on the stellar remains, the astronomers could piece together that prior to exploding, winds from the white dwarf cleared out a huge “cavity,” a region of very low-density surrounding the system. The explosion into this cavity was able to expand much faster than it otherwise would have. The ejected material would have traveled into the cavity, unimpeded by gas and dust and spread out quickly.

This is the first time that astronomers have been able to deduce that this type of cavity was created, and scientists say the results may have significant implications for theories of white-dwarf binary systems and Type Ia supernovae.

At about 85 light-years in diameter, RCW occupies a region of the sky that is slightly larger than the full moon. It lies in the southern constellation of Circinus.

Source: JPL

Posted on by Tammy Plotner

Did Asteroid Baptistina Kill The Dinosaurs? Think Other WISE…

It's long been thought that a giant asteroid, which broke up long ago in the main asteroid belt between Mars and Jupiter, eventually made its way to Earth and led to the extinction of the dinosaurs. New studies say that the dinosaurs may have been facing extinction before the asteroid strike, and that mammals were already on the rise. Image credit: NASA/JPL-Caltech

[/caption]

Once upon a time, about 65 million years ago, scientists hypothesize a sizable asteroid crashed into Earth and contributed to the extinction of the dinosaurs. The evidence is a 150-kilometer-wide crater located just off the Yucatan peninsula and legend has it the 10-kilometer-wide asteroid was a fragment of a larger parent – Baptistina. Now, thanks to observations by NASA’s Wide-field Infrared Survey Explorer (WISE), we just might have to re-think that theory.

While there’s almost absolutely no doubt an asteroid crash was responsible for a cataclysmic climate change, science has never been particularly sure of what asteroid caused it. A visible-light study done by terrestrial telescopes in 2007 pointed a finger at a huge asteroid known as Baptistina. The conjecture was that about 160 million years ago, it collided with another main belt asteroid and sent pieces flying. Even though it was plausible, the theory was quickly challenged and now infra-red evidence from WISE may finally lay this family of asteroids to rest.

“As a result of the WISE science team’s investigation, the demise of the dinosaurs remains in the cold case files,” said Lindley Johnson, program executive for the Near Earth Object (NEO) Observation Program at NASA Headquarters in Washington. “The original calculations with visible light estimated the size and reflectivity of the Baptistina family members, leading to estimates of their age, but we now know those estimates were off. With infrared light, WISE was able to get a more accurate estimate, which throws the timing of the Baptistina theory into question.”

For over a year, WISE took an infra-red survey of the entire sky and asteroid-hunting portion of the mission, called NEOWISE, cataloged 157,000 members – discovering an additional 33,000 new ones. By utilizing the more accurate infra-red data, the team examined 1,056 members of the Baptistina family and discovered its break-up was closer to 80 million years ago – less than half the time previously suggested. By better knowing their size and reflectivity, researchers are able to calculate how long it would take for Baptistina members to reach their current position. The results show that in order for this particular asteroid to have caused an extinction level event, that it would have had to have impacted Earth much sooner… like about 15 million years.

“This doesn’t give the remnants from the collision very much time to move into a resonance spot, and get flung down to Earth 65 million years ago,” said Amy Mainzer, a study co-author and the principal investigator of NEOWISE at NASA’s Jet Propulsion Laboratory (JPL) in Pasadena. Calif. “This process is thought to normally take many tens of millions of years.”

Like bouncing a super ball off the walls, resonance spots can jettison asteroids out of the main belt. This means a dinosaur-killing Baptistina event isn’t likely, but other asteroid families in NEOWISE study show similar reflective properties and one day we may be able to locate a responsible party.

“We are working on creating an asteroid family tree of sorts,” said Joseph Masiero, the lead author of the study. “We are starting to refine our picture of how the asteroids in the main belt smashed together and mixed up.”

Original Story Source: JPL/NASA News.

Posted on by Jason Major

Dust in the Wind

WISE image of the "Elephant Trunk" nebula. NASA/JPL-Caltech/WISE Team.

[/caption]

The stellar wind, that is! This beautiful image, taken by NASA’s Wide-Field Infrared Explorer (WISE) shows a vast ring of interstellar dust and gas being forced outwards by the wind and radiation from a massive star.

The star, HR8281, is located in the center of the image, the topmost star in a small triangular formation of blue stars to the upper left of the tip of a bright elongated structure – the end of the “elephant trunk” that gives the nebula its name. The star may not look like much, but HR8281’s powerful stellar wind is what’s sculpting the huge cloud of dust into the beautiful shapes seen in this infrared image.

Located 2,450 light-years from Earth, the Elephant’s Trunk Nebula spans 100 light-years. The “trunk” itself is about 30 light-years long. (That’s about, oh… 180 trillion miles!)

Structures like this are common in nebulae. They are formed when the stellar wind – the outpouring of ultraviolet radiation and charged particles that are constantly streaming off stars – blows away the gas and dust near a star, leaving only the densest areas. It’s basically erosion on a massive interstellar scale.

The tip of the "trunk" and the triangle of stars, the topmost of which is HR8281.

It’s not just a destructive process, though. Within those dense areas new stars can form… in fact, in the bright tip of the trunk above a small dark spot can be seen. That’s an area that’s been cleared by the creation of a new star. When a baby star “ignites” and its nuclear fusion factory turns on, its stellar wind clears away the dust and gas in the cloud it was formed from. Nebulae aren’t just pretty clouds in space… they’re stellar nurseries!

The red-colored stars in this image are other newborn stars, still wrapped in their dusty “cocoons”.

The colors used in this image represent specific wavelengths of infrared light. Blue and cyan (blue-green) represent light emitted at wavelengths of 3.4 and 4.6 microns, which is predominantly from stars. Green and red represent light from 12 and 22 microns, respectively, which is mostly emitted by dust.

Read more about this image on the WISE site here.

Image Credit: NASA/JPL-Caltech/WISE Team

Posted on by Nancy Atkinson

Runaway Star Creates Quite a Shock

A fast-moving star, Alpha Camelopardalis, creates a stunning bow shock in this new image from WISE. Credit: NASA/JPL-Caltech/WISE Team

[/caption]

Faster than a speeding bullet, this supergiant star looks like it might be wearing a red cape. Alpha Camelopardalis, the bright star in the middle of this image, is a runaway star, moving at incredible speeds – astronomers believe could be zooming along at somewhere between 680 and 4,200 kilometers per second (between 1.5 and 9.4 million miles per hour). The speed of this star is so fast, a huge bow shock is being created as the star moves through space. Alpha Cam’s bow shock can’t be seen in visible light, but WISE’s infrared detectors allow us to see this arc of heated gas and dust around the star.

Runaway stars are kicked into motion either through the supernova explosion of a companion star or through gravitational interactions with other stars in a cluster. The WISE team explains the bow shock:

“Because Alpha Cam is a supergiant star, it gives off a very strong wind. The speed of the wind is boosted in the forward direction the star is moving in space. When this fast-moving wind slams into the slower-moving interstellar material, a bow shock is created, similar to the wake in front of the bow of a ship in water. The stellar wind compresses the interstellar gas and dust, causing it to heat up and glow in infrared.”

Just as astronomers aren’t quite sure about the speed Alpha Cam is traveling, its distance is also somewhat uncertain, but it is probably somewhere between 1,600 and 6,900 light-years away. It is located in the constellation Camelopardis, near Ursa Major. (Right ascension: 4h 54m 03.0113s, declination: +66° 20′ 33.641”)

The colors used in this image represent specific wavelengths of infrared light. Stars are seen primarily in blue and cyan (blue-green), because they are emitting light brightly at 3.4 and 4.6 microns. Green represents 12-micron light, primarily emitted by dust. The red of the blow shock represents light emitted at 22 microns.

Source: WISE

Posted on by Nancy Atkinson

Gallery: WISE’s Greatest Hits

WISE First Light image. Image credit: NASA/JPL-Caltech/UCLA

[/caption]

The WISE mission is now over, with the spacecraft taking its final image on Feb. 1, 2011. WISE was a “cool” infrared mission, with the optics chilled to less than 20 degrees centigrade above absolute zero (20 Kelvins). In its low Earth orbit (523 km above the ground), the spacecraft explored the entire Universe and collected infrared light coming from everywhere in space and studied asteroids, the coolest and dimmest stars, and the most luminous galaxies. Expect to hear and see more from WISE, however in the future. More images will be released from the team in April and in the spring of 2012. Here’s a look back at some of the great images from WISE’s 13 months in space:

The red dot at the center of this image is the first near-Earth asteroid discovered by NASA's Wide-Field Infrared Survey Explorer, or WISE Image credit: NASA/JPL-Caltech/UCLA
The red smudge at the center of this picture is the first comet discovered by NASA's Wide-Field Infrared Survey Explorer, or WISE. Image credit: NASA/JPL-Caltech/UCLA
The immense Andromeda galaxy, also known as Messier 31 or simply M31, is captured in full in this February 2010 image from WISE. credit: NASA/JPL-Caltech/UCLA
NGC 3603, as seen by WISE. credit: NASA/JPL-Caltech/UCLA
NGC 1514, sometimes called the Crystal Ball nebula shows a new double ring feature in an image from WISE. Image credit: NASA/JPL-Caltech/UCLA
This image from WISE shows the Tadpole nebula. Image credit: NASA/JPL-Caltech/UCLA
The Heart and Soul nebulae are seen in this infrared mosaic from WISE. Image credit: NASA/JPL-Caltech/UCLA
An image released in August 2010 from WISE image of the Small Magellanic Cloud. Image credit: NASA/JPL-Caltech/WISE Team
This oddly colorful nebula is the supernova remnant IC 443 as seen by WISE. Image credit: NASA/JPL-Caltech/UCLA
The last image that will ever be taken by the WISE spacecraft. Credit: NASA/JPL-Caltech/WISE Team

And if you want to see how it all started, here’s a video of WISE’s launch:

Posted on by Nancy Atkinson

Mission Complete: NEOWISE Concludes Hunt for Near-Earth Objects

During its one-year mission, NASA's Wide-field Infrared Survey Explorer, or WISE, mapped the entire sky in infrared light. Among the multitudes of astronomical bodies that have been discovered by the NEOWISE portion of the WISE mission are 20 comets. Image credit: NASA/JPL-Caltech/UCLA

[/caption]

The WISE spacecraft has completed a special mission called NEOWISE, looking for small bodies in the solar system, and has discovered a plethora of previously unknown objects. The NEOWISE mission found 20 comets, more than 33,000 asteroids in the main belt between Mars and Jupiter, and 134 near-Earth objects (NEOs). More data from NEOWISE also have the potential to reveal a brown dwarf even closer to us than our closest known star, Proxima Centauri, if such an object does exist. Likewise, if there is a hidden gas-giant planet in the outer reaches of our solar system, data from WISE and NEOWISE could detect it.

“WISE has unearthed a mother lode of amazing sources, and we’re having a great time figuring out their nature,” said Edward (Ned) Wright, the principal investigator of WISE at UCLA.

“Even just one year of observations from the NEOWISE project has significantly increased our catalog of data on NEOs and the other small bodies of the solar systems,” said Lindley Johnson, NASA’s program executive for the NEO Observation Program.

The NEOs are asteroids and comets with orbits that come within 45 million kilometers (28 million miles) of Earth’s path around the sun.

The NEOWISE mission made use of the the WISE spacecraft, the Wide-field Infrared Survey Explorer that launched in December 2009. WISE scanned the entire celestial sky in infrared light about 1.5 times. It captured more than 2.7 million images of objects in space, ranging from faraway galaxies to asteroids and comets close to Earth.

However, in early October 2010, after completing its prime science mission, the spacecraft ran out of the frozen coolant that keeps its instrumentation cold. But two of its four infrared cameras remained operational, which were still optimal for asteroid hunting, so NASA extended the NEOWISE portion of the WISE mission by four months, with the primary purpose of hunting for more asteroids and comets, and to finish one complete scan of the main asteroid belt.

Now that NEOWISE has successfully completed a full sweep of the main asteroid belt, the WISE spacecraft will go into hibernation mode and remain in polar orbit around Earth, where it could be called back into service in the future.

In addition to discovering new asteroids and comets, NEOWISE also confirmed the presence of objects in the main belt that had already been detected. In just one year, it observed about 153,000 rocky bodies out of approximately 500,000 known objects. Those include the 33,000 that NEOWISE discovered.

NEOWISE also observed known objects closer and farther to us than the main belt, including roughly 2,000 asteroids that orbit along with Jupiter, hundreds of NEOs and more than 100 comets.

These observations will be key to determining the objects’ sizes and compositions. Visible-light data alone reveal how much sunlight reflects off an asteroid, whereas infrared data is much more directly related to the object’s size. By combining visible and infrared measurements, astronomers also can learn about the compositions of the rocky bodies — for example, whether they are solid or crumbly. The findings will lead to a much-improved picture of the various asteroid populations.

NEOWISE took longer to survey the whole asteroid belt than WISE took to scan the entire sky because most of the asteroids are moving in the same direction around the sun as the spacecraft moves while it orbits Earth. The spacecraft field of view had to catch up to, and lap, the movement of the asteroids in order to see them all.

“You can think of Earth and the asteroids as racehorses moving along in a track,” said Amy Mainzer, the principal investigator of NEOWISE at NASA’s Jet Propulsion Laboratory in Pasadena, Calif. “We’re moving along together around the sun, but the main belt asteroids are like horses on the outer part of the track. They take longer to orbit than us, so we eventually lap them.”

NEOWISE data on the asteroid and comet orbits are catalogued at the NASA-funded International Astronomical Union’s Minor Planet Center, a clearinghouse for information about all solar system bodies at the Smithsonian Astrophysical Observatory in Cambridge, Mass. The science team is analyzing the infrared observations now and will publish new findings in the coming months.

The first batch of observations from the WISE mission will be available to the public and astronomical community in April.

Source: NASA

Posted on by Nancy Atkinson

The Real News about Ophiuchus: There’s a Runaway Star Plowing Through It

The blue star near the center of this image is Zeta Ophiuchi, a runaway star plowing through the constellation Ophiuchus. Credit: NASA/JPL-Caltech/UCLA

Lots of folks seem to be up in arms about the “new” sign in the zodiac, Ophiuchus, and the news that all the star signs are no longer in sync with the actual constellations. Of course, *most* of us already knew that news is centuries old, and that the zodiac has no effect whatsoever on our lives and it never has (most readers of Universe Today, anyway!) Now for some real news about Ophiuchus: NASA’s Wide-field Infrared Survey Explorer, or WISE has found a massive, runaway star, called Zeta Ophiuchi that is plowing through a cloud of space dust in Ophiuchus. The result is a brilliant bow shock, seen here as a yellow arc in this stunning new image.
Continue reading “The Real News about Ophiuchus: There’s a Runaway Star Plowing Through It”

Posted on by Nancy Atkinson

WISE Captures an Infrared Shock Wave

This oddly colorful nebula is the supernova remnant IC 443 as seen by WISE. Image credit: NASA/JPL-Caltech/UCLA

[/caption]

From a JPL press release:

A circular rainbow appears like a halo around an exploded star in this new view of the IC 443 nebula from NASA’s Wide-field Infrared Survey Explorer, or WISE.

When massive stars die, they explode in tremendous blasts, called supernovae, which send out shock waves. The shock waves sweep up and heat surrounding gas and dust, creating supernova remnants like the one pictured here. The supernova in IC 443 happened somewhere between 5,000 and 10,000 years ago.

In this WISE image, infrared light has been color-coded to reveal what our eyes cannot see. The colors differ primarily because materials surrounding the supernova remnant vary in density. When the shock waves hit these materials, different gases were triggered to release a mix of infrared wavelengths.

The supernova remnant’s northeastern shell, seen here as the violet-colored semi-circle at top left, is composed of sheet-like filaments that are emitting light from iron, neon, silicon and oxygen gas atoms and dust particles heated by a fast shock wave traveling at about 100 kilometers per second, or 223,700 mph.

The smaller southern shell, seen in bright bluish colors, is constructed of clumps and knots primarily emitting light from hydrogen gas and dust heated by a slower shock wave traveling at about 30 kilometers per second, or 67,100 miles per hour. In the case of the southern shell, the shock wave is interacting with a nearby dense cloud. This cloud can be seen in the image as the greenish dust cutting across IC 443 from the northwest to southeast.

IC 443 can be found near the star Eta Geminorum, which lies near Castor, one of the twins in the constellation Gemini.

Posted on by Nancy Atkinson

WISE Captures a Glowing Cylinder in Space

NGC 1514, sometimes called the "Crystal Ball" nebula shows a new double ring feature in an image from WISE. Image credit: NASA/JPL-Caltech/UCLA

[/caption]

It’s not like we’ve never seen the planetary nebula NGC 1514 before, but we’ve never seen it though WISE’s infrared eyes, until now. And in a stunning surprise, cylindrical rings appear to be encircling the dying star, like a neon-lit carousel, or perhaps like rolling tire surrounding a glowing blob. “I just happened to look up one of my favorite objects in our WISE catalogue and was shocked to see these odd rings,” said Michael Ressler, a member of the WISE science team at JPL. “This object has been studied for more than 200 years, but WISE shows us it still has surprises.

Space station from the movie 2001: A Space Odyssey.

At first glance the rings look like the double-ringed space station in the movie 2001: A Space Odyssey. (Too bad the Bad Astronomer beat me to that likeness. He also compared it to a tuna can.)

Other people see different things in this image.

“I am reminded of the jellyfish exhibition at the Monterey Bay Aquarium — beautiful things floating in water, except this one is in space,” said Edward (Ned) Wright, the principal investigator of the WISE mission at UCLA, and a co-author of a paper on the findings, reported in the Astronomical Journal.

WISE was able to spot the rings for the first time because their dust is being heated and glows with the infrared light that WISE can detect. In visible-light images, the rings are hidden from view, overwhelmed by the brightly fluorescing clouds of gas.

Here’s what NGC 1514 looks like in visible light from a ground observatory:

NGC1514 in visible light. Image credit: Digitized Sky Survey/STScI

The object is actually a pair of stars, seen as a single dot at the center of the blue orb. One star is a dying giant somewhat heavier and hotter than our sun, and the other was an even larger star that has now contracted into a dense body called a white dwarf. As the giant star ages, it sheds some its outer layers of material. An inner shell of ejected material is seen in bright, light blues. An outer shell can also be seen in more translucent shades of blue.

This planetary nebula is also called the “Crystal Ball” nebula, and Ressler said although NGC 1514’s structure looks unique, is probably similar in overall geometry to other hour-glass nebulae, such as the Engraved Hourglass Nebula.

Planetary Nebula MyCn18: An Hourglass Pattern Around a Dying Star. Credit: Raghvendra Sahai and John Trauger (JPL), the WFPC2 science team, and NASA.

The structure looks different in WISE’s view because the rings are detectable only by their heat; they do not fluoresce at visible wavelengths, as do the rings in the other objects.

The WISE science team says that more oddballs like NGC 1514 are sure to turn up in the plethora of WISE data — the first batch of which will be released to the astronomical community in spring 2011.

Source: JPL