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

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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

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”

SOFIA Opens New Window on Star Formation in Orion

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SOFIA’s mid-infrared image of Messier 42 (right) with comparison images of the same region made at other wavelengths by the Hubble Space Telescope (left) and European Southern Observatory (middle). (Credits: Visible-light image: NASA/ESA/HST/AURA/STScI/O’Dell & Wong; Near-IR image: ESO/McCaughrean et al.; Mid-IR image: NASA/DLR/SOFIA/USRA/DSI/FORCAST Team)

From a NASA Press Release:

A mid-infrared mosaic image from the Stratospheric Observatory for Infrared Astronomy, or SOFIA, offers new information about processes of star formation in and around the nebula Messier 42 in the constellation Orion. The image data were acquired using the Faint Object Infrared Camera for the SOFIA Telescope, or FORCAST, by principal investigator Terry Herter, of Cornell University during SOFIA’s Short Science 1 observing program in December 2010.
Continue reading “SOFIA Opens New Window on Star Formation in Orion”

SOFIA Telescope Makes First Science Flight

The Stratospheric Observatory for Infrared Astronomy, or SOFIA, 747SP basks in the light of a full moon shining over California’s Mojave Desert. NASA photographer Tom Tschida shot this telephoto image on October 22, 2010 NASA Photo / Tom Tschida

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SOFIA, NASA’s airplane-based Stratospheric Observatory for Infrared Astronomy made its first science flight on Wednesday, to help demonstrate the aircraft’s potential to make discoveries about the infrared universe. The new observatory uses a modified 747 airplane to carry a German-built 2.5 meter (100 inch) reflecting telescope, and on its initial flight to gather science data, the plane flew for about 10 hours.

“These initial science flights mark a significant milestone in SOFIA’s development and ability to conduct peer-reviewed science observations,” said NASA Astrophysics Division Director Jon Morse. “We anticipate a number of important discoveries from this unique observatory, as well as extended investigations of discoveries by other space telescopes.”

SOFIA is anticipated to have a 20-year lifespan that will enable a wide variety of astronomical science observations not possible from other Earth and space-borne observatories.

Cruising at altitudes between 39,000 and 45,000 feet, researchers hope to study how stars and planets are born, how organic substances form in interstellar space, and how supermassive black holes feed and grow.

SOFIA is a 100-inch diameter infrared telescope, and the instruments can analyze light from a wide
range of celestial objects, including warm interstellar gas and dust of bright star forming regions, by observing wavelengths between 0.3 and 1,600 microns. A micron equals one millionth of a meter. For
comparison, the human eye sees light with wavelengths between 0.4 and 0.7 microns.

The first three science flights, phase one of SOFIA’s early science program, will employ the Faint Object InfraRed Camera for the SOFIA Telescope (FORCAST) instrument developed by Cornell University and
led by principal investigator Terry Herter. FORCAST observes the mid-infrared spectrum from five to 40 microns.

Researchers used the FORCAST camera on SOFIA during a test flight two weeks ago to produce infrared images of areas within the Orion star-formation complex, a region of the sky for which more extensive
data were collected during the Nov. 30 flight. The image below is of this region. You can see more images at this link.

This infrared image of the heart of the Orion star-formation complex was taken by SOFIA’s FORCAST mid-infrared camera. Credit: NASA

SOFIA flies from NASA’s Dryden Aircraft Operations Facility in Palmdale, California.

Herschel Provides Gravitational Lens Bonanza

The image shows the first area of sky viewed as part of the Herschel-ATLAS survey. The five inset show enlarged views of the five distant galaxies whose images are being gravitationally lensed by foreground galaxies (unseen by Herschel). The distant galaxies are not only very bright, but also very red in colour in this image, showing that they are brighter at the longer wavelengths measured by the SPIRE instrument. Image credits: ESA/SPIRE/Herschel-ATLAS/SJ Maddox (top); ESA/NASA/JPL-Caltech/Keck/SMA (bottom).
The image shows the first area of sky viewed as part of the Herschel-ATLAS survey. The five inset show enlarged views of the five distant galaxies whose images are being gravitationally lensed by foreground galaxies (unseen by Herschel). The distant galaxies are not only very bright, but also very red in colour in this image, showing that they are brighter at the longer wavelengths measured by the SPIRE instrument. Image credits: ESA/SPIRE/Herschel-ATLAS/SJ Maddox (top); ESA/NASA/JPL-Caltech/Keck/SMA (bottom).

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One of the predictions of Einstein’s predictions from general relativity was that gravity could distort space itself and potentially, act as a lens. This was spectacularly confirmed in 1919 when, during a solar eclipse, Arthur Eddington observed stars near the Sun were distorted from their predicted positions. In 1979, this effect was discovered at much further distances when astronomers found it to distort the image of a distant quasar, making one appear as two. Several other such cases have been discovered since then, but these instances of gravitational lensing have proven difficult to find. Searches for them have had a low success rate in which less than 10% of candidates are confirmed as gravitational lenses. But a new method using data from Herschel may help astronomers discover many more of these rare occurrences.

The Herschel telescope is one of the many space telescopes currently in use and explores the portion of the spectrum from the far infrared to the submillimeter regime. A portion of its mission is to produce a large survey of the sky resulting in the Herschel ATLAS project which will take deep images of over 550 square degrees of the sky.

While Herschel explores this portion of the electromagnetic spectrum in far greater detail than its predecessors, in many ways, there’s not much to see. Stars emit only very faintly in this range. The most promising targets are warm gas and dust which are better emitters, but also far more diffuse. But it’s this combination of facts that will allow Herschel to potentially discover new lenses with improved efficiency.

The reason is that, although galaxies lack strong emission in this regime in the modern universe, ancient galaxies gave off far more since during the first 4 billion years. During that time, many galaxies were dominated by dust being warmed by star formation. Yet due to their distance, they too should be faint… Unless a gravitational lens gets in the way. Thus, the majority of small, point-like sources in the ALTAS collection are likely to be lensed galaxies. As Dr Mattia Negrello, of the Open University and lead researcher of the study explains, “The big breakthrough is that we have discovered that many of the brightest sources are being magnified by lenses, which means that we no longer have to rely on the rather inefficient methods of finding lenses which are used at visible and radio wavelengths.”

These panels show a zoom of one of the lenses, with high resolution images from Keck (optical light, blue) and the submillimeter Array (sub-millimetre light, red). Image credits: ESA/NASA/JPL-Caltech/Keck/SMA
These panels show a zoom of one of the lenses, with high resolution images from Keck (optical light, blue) and the submillimeter Array (sub-millimetre light, red). Image credits: ESA/NASA/JPL-Caltech/Keck/SMA

Already, this new technique has turned up at least five strong candidates. A paper, to be published in the current issue of Science discusses them. Each of them received followup observations from the Z-Spec spectrometer on the California Institute of Technology Submillimeter Observatory. The furthest of these these objects, labeled as ID81, showed a prominent IR spectral line had a redshift of 3.04, putting it at a distance of 11.5 billion lightyears. Additionally, each system showed the spectral profile of the foreground galaxy, demonstrating that the combined light received was indeed two galaxies and the bright component was a gravitational lens.

This method of using gravitational lenses will allow the Herschel team to probe distant galaxies in detail never before achieved. As with all telescopes, longer wavelengths of observations result in less resolution which means that, even if one of the distant systems were to be broken into distinct portions, Herschel would be unable to resolve them. But the fact that we can see them at all means their spectral signatures of the galaxies as a whole can still be studied. Additionally, as Professor Steve Eales from Cardiff University and the other leader of the survey noted: “We can also use this technique to study the lenses themselves.” This potential to explore the mass of the nearby galaxies may help astronomers to understand and constrain the enigmatic Dark Matter that makes up ~80% of the mass in our universe.

Dr Loretta Dunne of Nottingham University and joint-leader of the Herschel-ATLAS survey adds, “What we’ve seen so far is just the tip of the iceberg. Wide area surveys are essential for finding these rare events and since Herschel has only covered one thirtieth of the entire Herschel-ATLAS area so far, we expect to discover hundreds of lenses once we have all the data. Once found, we can probe the early Universe on the same physical scales as we can in galaxies next door.”

New VISTA Within the Unicorn

A new infrared image shows the nearby star formation region Monoceros R2, located some 2700 light-years away in the constellation of Monoceros (the Unicorn).Credit: ESO/J. Emerson/VISTA. Acknowledgment: Cambridge Astronomical Survey Unit

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What a gorgeous new infrared image of the region within the Monoceros (Unicorn) constellation taken from ESO’s Paranal Observatory in northern Chile with the amazing VISTA: the Visible and Infrared Survey Telescope for Astronomy. This telescope has a huge field of view, a large mirror and a very sensitive camera and has been churning out image after fantastic image. In this one, VISTA is able to penetrates the dark curtain of cosmic dust and reveals in astonishing detail the folds, loops and filaments sculpted from the dusty interstellar matter by intense particle winds and the radiation emitted by hot young stars.

“When I first saw this image I just said ‘Wow!’” said Jim Emerson, of Queen Mary, University of London and leader of the VISTA consortium. “I was amazed to see all the dust streamers so clearly around the Monoceros R2 cluster, as well as the jets from highly embedded young stellar objects. There is such a great wealth of exciting detail revealed in these VISTA images.”

It shows an active stellar nursery hidden inside a massive dark cloud rich in molecules and dust. Although the Unicorn appears close in the sky to the more familiar Orion Nebula it is actually almost twice as far from Earth, at a distance of about 2,700 light-years.

The width of VISTA’s field of view is equivalent to about 80 light-years at this distance. Since the dust is largely transparent at infrared wavelengths, many young stars that cannot be seen in visible-light images become apparent. The most massive of these stars are less than ten million years old.

In visible light a grouping of massive hot stars creates a beautiful collection of reflection nebulae where the bluish starlight is scattered from parts of the dark, foggy outer layers of the molecular cloud. However, most of the new-born massive stars remain hidden as the thick interstellar dust strongly absorbs their ultraviolet and visible light.

This new image was created from exposures taken in three different parts of the near-infrared spectrum. In molecular clouds like Monoceros R2, the low temperatures and relatively high densities allow molecules to form, such as hydrogen, which under certain conditions emit strongly in the near infrared. Many of the pink and red structures that appear in the VISTA image are probably the glows from molecular hydrogen in outflows from young stars.

Read more about this image at the ESO website.

Herschel Finds Water Around a Carbon Star

Herschel image of the carbon star CW Leonis. The arc visible to the left of the star is a bow showck, where the stellar wind encounters the interstellar medium. ESA/PACS/SPIRE/MESS Consortia

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There’s something strange going on around the red giant star CW Leonis (a.k.a. IRC+10216). Deep within the star’s carbon-rich veil, astronomers have detected water vapor where no water should be.

CW Leonis is similar in mass to the sun, but much older and much larger. It is the nearest red giant to the sun, and in its death throes it has hidden itself in a sooty, expanding cloud of carbon-rich dust. This shroud makes CW Leonis almost invisible to the naked eye, but at some infrared wavelengths it is the brightest object in the sky.

Water was originally discovered around CW Leonis in 2001 when the Submillimeter Wave Astronomy Satellite (SWAS) found the signature of water in the chilly outer reaches of the star’s dusty envelope at a temperature of only 61 K. This water was assumed to be evidence for vaporizing comets and other icy objects around the expanding star. New observations with the SPIRE and PACS spectrometers on the Herschel Space Observatory reveal that there’s something much more surprising going on.

“Thanks to Herschel’s superb sensitivity and spectral resolution, we were able to identify more than 60 lines of water, corresponding to a whole series of energetic levels of the molecule,” explains Leen Decin from the University of Leuven and leader of the study. The newly-detected spectral lines indicate that the water vapor is not all in the cold outer envelope of the star. Some of it is much closer to the star, where temperatures reach 1000 K.

No icy fragments could exist that close to the star, so Decin and colleagues had to come up with a new explanation for the presence of the hot water vapor. Hydrogen is abundant in the envelope of gas and dust surrounding carbon stars like  CW Leonis, but the other building block of water, oxygen, is typically bound up in molecules like carbon monoxide (CO) and silicon monoxide (SiO). Ultraviolet light can split these molecules, releasing their stored oxygen, but red giant stars don’t make much UV light so it has to come from somewhere else.

An illustration of the chemical reactions caused by interstellar UV light interacting with molecules surrounding CW Leonis. ESA. Adapted from L. Decin et al. (2010)

The dusty envelopes around carbon stars are known to be clumpy, and that turns out to be the key to explaining the mysterious water vapor. The patchy structure of the shroud around CW Leonis lets UV light from interstellar space into the depths of the star’s envelope. “Well within the envelope, UV photons trigger a set of reactions that can produce the observed distribution of water, as well as other, very interesting molecules, such as ammonia (NH3),” says Decin. “This is the only mechanism that explains the full range of the water’s temperature.”

In the coming months, astronomers will test this hypothesis by using Herschel to search for evidence of water near other carbon stars.

Ambitious Survey Spots Stellar Nurseries

VISTA Magellanic Cloud Survey view of the Tarantula Nebula. Credit: ESO/M.-R. Cioni/VISTA Magellanic Cloud survey. Acknowledgment: Cambridge Astronomical Survey Unit

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ESO’s VISTA telescope has begun a new survey of the Magellanic Cloud, and this spectacular image of the Tarantula Nebula is a taste of great things to come from this near-infrared scan of the more interesting galaxies in our neighborhood. This panoramic near-infrared view captures the nebula itself in great detail as well as the rich surrounding area of sky. “This view is of one of the most important regions of star formation in the local Universe — the spectacular 30 Doradus star-forming region, also called the Tarantula Nebula,” said the leader of the survey team, Maria-Rosa Cioni from the University of Hertfordshire. “At its core is a large cluster of stars called RMC 136, in which some of the most massive stars known are located.”

VISTA is a new survey telescope at the Paranal Observatory in Chile, and is equipped with a huge camera that detects light in the near-infrared part of the spectrum, revealing a wealth of detail about astronomical objects that gives us insight into the inner workings of astronomical phenomena. Near-infrared light has a longer wavelength than visible light, fortunately, it can pass through much of the dust that would normally obscure the views that our eyes can see. This makes it particularly useful for studying objects such as young stars that are still enshrouded in the gas and dust clouds from which they formed. Another powerful aspect of VISTA is the large area of the sky that its camera can capture in each shot.
The VISTA Magellanic Cloud Survey is one of six huge near-infrared surveys of the southern sky that will take up most of the first five years of operations of VISTA.

This project will scan a vast area — 184 square degrees of the sky (corresponding to almost one thousand times the apparent area of the full Moon) including our neighboring galaxies the Large and Small Magellanic Clouds. The end result will be a detailed study of the star formation history and three-dimensional geometry of the Magellanic system.

“The VISTA images will allow us to extend our studies beyond the inner regions of the Tarantula into the multitude of smaller stellar nurseries nearby, which also harbor a rich population of young and massive stars,” said Chris Evans who is part of the VMC team. “Armed with the new, exquisite infrared images, we will be able to probe the cocoons in which massive stars are still forming today, while also looking at their interaction with older stars in the wider region.”

The wide-field image shows a host of different objects. The bright area above the centre is the Tarantula Nebula itself, with the RMC 136 cluster of massive stars in its core. To the left is the NGC 2100 star cluster. To the right is the tiny remnant of the supernova SN1987A (eso1032). Below the centre are a series of star-forming regions including NGC 2080 — nicknamed the “Ghost Head Nebula” — and the NGC 2083 star cluster.

See more images, zoomable images, and movies of the Tarantula Nebula at the ESO website.

WISE Cryostat is Depleting

An image released in August 2010 from WISE image of the Small Magellanic Cloud. Image credit: NASA/JPL-Caltech/WISE Team

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NASA’s Wide-field Infrared Survey Explorer, or WISE, is losing its cool. The spacecraft is running out of the frozen coolant needed to keep its heat-sensitive instrument chilled, and will only be in operation for 2-3 more months. While the spacecraft was designed to be rather short-lived – 7 to 10 months — it still is sad to see the mission winding down. But WISE has completed its primary mission, a full scan of the entire sky in infrared light, which was accomplished by July 17, 2010. The mission has taken more than 1.5 million snapshots so far, uncovering hundreds of millions of objects, including asteroids, stars and galaxies. It has discovered more than 29,000 new asteroids to date, more than 100 near-Earth objects and 15 comets.

The telescope has two coolant tanks that keep the spacecraft’s normal operating temperature at 12 Kelvin (minus 438 degrees Fahrenheit). The outer, secondary tank is now depleted, causing the temperature to increase. One of WISE’s infrared detectors, the longest-wavelength band most sensitive to heat, stopped producing useful data once the telescope warmed to 31 Kelvin (minus 404 degrees Fahrenheit). The primary tank still has a healthy supply of coolant, and data quality from the remaining infrared detectors remains high.

WISE is continuing a second survey of about one-half the sky as originally planned. It’s possible the remaining coolant will run out before that scan is finished. Scientists say the second scan will help identify new and nearby objects, as well as those that have changed in brightness. It could also help to confirm oddball objects picked up in the first scan.

NASA is hoping to find more Near Earth Objects with WISE’s remaining days of operations.
“WISE’s prime mission was to do an infrared background map,” said Lindley Johnson, program executive for the Near-Earth Objects Observation program at NASA, speaking at a workshop this week to define objectives for exploring asteroids. “But we realized in talking with scientists that it would also make a good asteroid detector by comparing images. It has done a good job of finding a lot of objects for us.”

Source: NASA

WISE Covers the Heart and Soul of Infrared Astronomy

The Heart and Soul nebulae are seen in this infrared mosaic from WISE. Image credit: NASA/JPL-Caltech/UCLA

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In about six months’ time, NASA’s WISE mission, the Wide-field Infrared Survey Explorer, has captured almost a million images, covering about three-quarters, or 30,000 square degrees, of the sky. At the 216th American Astronomical Society meeting today, astronomers released a new mosaic of two bubbling clouds in space, known as the Heart and Soul nebulae.

“This image actually has two hearts; one is a Valentine’s Day heart, and the other is a surgical heart that you have in your body,” said Ned Wright of the University of California, Los Angeles who presented the new picture. “This new image demonstrates the power of WISE to capture vast regions. We’re looking north, south, east and west to map the whole sky.”

To make this huge mosaic WISE stared at this region of space which lies about 6,000 light-years away in the constellation Cassiopeia, for 3.5 hours of total exposure time, taking 1,147 images.

Both these nebulae are massive star-making factories, marked by giant bubbles blown into surrounding dust by radiation and winds from the stars. The infrared vision of WISE allows it to see into the cooler and dustier crevices of clouds like these, where gas and dust are just beginning to collect into new stars.

WISE will complete its first map of the sky in July 2010, and then spend the next three months surveying much of the sky a second time, before the solid-hydrogen coolant needed to chill its infrared detectors runs dry. Wright said the first installment of the public WISE catalog will be released in summer 2011.
Wright marveled at how in the span of his career he has gone from observing in just 4 pixels to now observing with WISE in almost 4 million pixels.

“It’s been an amazing progress in IR astronomy, with cameras growing by a factor of a million in power in just a few decades,” he said.

Screen shot from Wright's presentation at the AAS meeting showing how much of the sky WISE has covered. The small green box shows the area of the Heart and Soul nebulae.

Spotting NEO’s

One goal of the WISE mission is to study asteroids throughout our solar system and to find out more about how they vary in size and composition. Infrared helps with this task because it can get better size measurements of the space rocks than visible light.

So far, WISE has observed more than 60,000 asteroids, most of which lie in the main belt, orbiting between Mars and Jupiter. About 11,000 of these objects are newly discovered, and about 50 of them belong to a class of near-Earth objects, which have paths that take them within about 48 million kilometers (30 million miles) of Earth’s orbit.

“As WISE is orbiting the Earth, we are sweeping through the solar system like radar, and building up a map of what the solar system looks like in near infrared, looking for Near Earth Objects,” said astronomer Tommy Grav of Johns Hopkins University.

Grav told Universe Today so far there haven’t been any big surprises in the amount of NEOs the WISE team is finding. “We haven’t done full analysis of all the data WISE has sent back, but we’re finding about what we expected. We’re right in the ballpark of what we expected to find.”

The mission also studies the Trojans, asteroids that run along with Jupiter in its orbit around the sun in two packs — one in front of and one behind the gas giant. It has seen more than 800 of these objects, and by the end of the mission, should have observed about half of all 4,500 known Trojans. The results will address dueling theories about how the outer planets evolved.

“We can basically confirm and fill in the gap between ground based observations and the Spitzer Space Telescope’s observations of the Trojan asteroids,” Grav said.

Grav said WISE is an outstanding observatory. “We’ve basically done in six months what it took over 100 years to do in the optical.”

Sources: NASA, AAS press conference