December 9, 2008, 10:13 PM CT

Hubble finds carbon dioxide on an extrasolar planet

The Jupiter-sized planet, called HD 189733b, is too hot for life. But new Hubble observations are a proof-of-concept demonstration that the basic chemistry for life can be measured on planets orbiting other stars. Organic compounds can also be a by-product of life processes and their detection on an Earth-like planet may someday provide the first evidence of life beyond Earth.

Prior observations of HD 189733b by Hubble and the Spitzer Space Telescope found water vapour. Earlier this year Hubble found methane in the planet's atmosphere.

"This is exciting because Hubble is allowing us to see molecules that probe the conditions, chemistry, and composition of atmospheres on other planets," says first author Mark Swain of The Jet Propulsion Laboratory in Pasadena, USA. "Thanks to Hubble we're entering an era where we are rapidly going to expand the number of molecules we know about on other planets".

The international team of astronomers used Hubble's Near Infrared Camera and Multi-Object Spectrometer (NICMOS) to study infrared light emitted from the planet, which lies 63 light-years away. Gases in the planet's atmosphere absorb certain wavelengths of light from the planet's hot glowing interior. The team identified not only carbon dioxide, but also carbon monoxide. The molecules leave their own unique spectral fingerprint on the radiation from the planet that reaches Earth. This is the first time a near-infrared emission spectrum has been obtained for an extrasolar planet......... Posted by: Sean      Read more         Source

November 21, 2008, 8:45 PM CT

Mars Express observes aurorae

Researchers using ESA's Mars Express have produced the first crude map of aurorae on Mars. These displays of ultraviolet light appear to be located close to the residual magnetic fields generated by Mars's crustal rocks. They highlight many mysteries about the way Mars interacts with electrically charged particles originating from the Sun.

The aurorae on Mars were discovered in 2004 using the SPICAM ultraviolet and infrared atmospheric spectrometer on board Mars Express. They are a powerful tool with which researchers can investigate the composition and structure of the Red Planet's atmosphere.

Now Francois Leblanc, from the Service d'Aeronomie, IPSL/CNRS, France and his colleagues have announced the results of coordinated observation campaigns using SPICAM, the MARSIS sub-surface sounding radar altimeter's radar, and the energetic neutral atoms analyser, ASPERA's electron spectrometer on Mars Express.

They have observed nine new auroral emission events, which have allowed them to make the first crude map of auroral activity on Mars. They see that the aurorae seem to be located near regions where the martian magnetic field is the strongest. MARSIS had previously observed higher-than-expected electrons in similar regions. This suggests, eventhough it does not prove, that the magnetic fields help to create the aurorae......... Posted by: Sean      Read more         Source

November 14, 2008, 8:47 PM CT

Surprising flashes from a possible magnetar

By means of the high-speed photometer OPTIMA of the Max Planck Institute for Extraterrestrial Physics (MPE), a team of MPE researchers may have detected an unexpected new sub-category of astronomical objects. The object appears to be a magnetar with bursts in the visible part of the spectrum, in contrast to the X-ray and gamma flashes, which are considered to be characteristic for magnetars (Nature, September 2008).

A notice was received by the researchers around Alexander Stefanescu in real time, pertaining to a brief outburst of high-energy radiation detected by the NASA Swift satellite. After observing the location of this outburst, they quickly discovered they had not observed a normal gamma-ray burst (GRB): Instead of the slow decay in brightness commonly expected along with occasional short episodes of re-brightening, the researchers observed sudden bright flashes. The observations grew stranger still, when the activity hadn't ceased the next night, but had in fact become stronger, not ceasing completely until several nights had passed.

Examining the radiation emitted during an X-ray outburst, the scientists observed that a part of the radiation had been absorbed by hydrogen gas on the way from the object to Earth. After mapping the gas masses along the line of sight it became clear that the object was most probably situated within our own Galaxy. This meant it could not have been a normal GRB, because these commonly do not happen in our "immediate astronomical vicinity", but in distant galaxies......... Posted by: Sean      Read more         Source

November 14, 2008, 8:40 PM CT

Winds of Baby Stars

New high-resolution observations with the VLT Interferometer of the European Southern Observatory in Chile reveal gas infall and outflow processes in the direct environment of six young stars. The origin of the gas emission from these stars is still strongly debated, since earlier investigations could not resolve the gas distribution close to the star. An international team of astronomers, led by Stefan Kraus from the Max Planck Institute for Radio Astronomy in Bonn, Gera number of and Eric Tatulli from the Observatoire de Grenoble in France used the AMBER instrument to measure the geometry of atomic and molecular gas in the inner disk regions. Surprisingly, they observed that the gas emission can trace very distinct physical mechanisms. These processes include infall of material onto the star as well as gas which is ejected from the system, likely in a disk wind. The results are published in this week's issue of "Astronomy & Astrophysics".

An international team of astronomers led by Stefan Kraus from the Max Planck Institute for Radio Astronomy in Bonn, Gera number of, and Eric Tatulli from the Observatoire de Grenoble, France, used the unique capability of the VLT near-infrared interferometer, coupled with spectroscopy, to probe the gaseous environment of a specific type of young stars called Herbig Ae/Be stars. These are young stars of intermediate mass (approximately 2 to 10 solar masses) which are still contracting and which often show strong line emission......... Posted by: Sean      Read more         Source

November 13, 2008, 10:35 PM CT

First images of newly-discovered solar system

Astronomers for the first time have taken snapshots of a multi-planet solar system, much like ours, orbiting another star. The new solar system orbits a dusty young star named HR8799, which is 140 light years away and about 1.5 times the size of our sun. Three planets, roughly 10, 10 and 7 times the mass of Jupiter, orbit the star. The size of the planets decreases with distance from the parent star, much like the giant planets do in our system.

And there may be more planets out there, but researchers say they just haven't seen them yet.

"Every extrasolar planet detected so far has been a wobble on a graph. These are the first pictures of an entire system," said Bruce Macintosh, an astrophysicist from Lawrence Livermore National Laboratory and one of the key authors of a paper appearing in the Nov. 13 issue of Science Express. "We've been trying image planets for eight years with no luck and now we have pictures of three planets at once".

Using high-contrast, near-infrared adaptive optics observations with the Keck and Gemini telescopes, the team of scientists from Livermore, the NRC Herzberg Institute of Astrophysics in Canada, Lowell Observatory, University of California Los Angeles, and several other institutions were able to see three orbiting planetary companions to HR8799......... Posted by: Sean      Read more         Source

October 20, 2008, 10:11 PM CT

Cosmic Lens Reveals Distant Galactic Violence

By cleverly unraveling the workings of a natural cosmic lens, astronomers have gained a rare glimpse of the violent assembly of a young galaxy in the early Universe. Their new picture suggests that the galaxy has collided with another, feeding a supermassive black hole and triggering a tremendous burst of star formation.

The astronomers used the National Science Foundation's Very Large Array (VLA) radio telescope to look at a galaxy more than 12 billion light-years from Earth, seen as it was when the Universe was only about 15 percent of its current age. Between this galaxy and Earth lies another distant galaxy, so perfectly aligned along the line of sight that its gravity bends the light and radio waves from the farther object into a circle, or "Einstein Ring".

This gravitational lens made it possible for the researchers to learn details of the young, distant galaxy that would have been unobtainable otherwise.

"Nature provided us with a magnifying glass to peer into the workings of a nascent galaxy, providing an exciting look at the violent, messy process of building galaxies in the early history of the Universe," said Dominik Riechers, who led this project at the Max Planck Institute for Astronomy in Gera number of and now is a Hubble Fellow at the California Institute of Technology (Caltech)......... Posted by: Sean      Read more         Source

October 15, 2008, 5:32 PM CT

Star Count Goes Global

Schoolchildren, families and citizen researchers around the world will gaze skyward after dark from Oct. 20 to Nov.3, 2008, looking for specific constellations and then sharing their observations through the Internet.

The Great World Wide Star Count, now in its second year, helps researchers map light pollution globally while educating participants about the stars.

The event, which is open to everyone who wants to participate, is organized by the Windows to the Universe project at the University Corporation for Atmospheric Research (UCAR) in Boulder, Colo., in conjunction with planetariums and scientific societies across the country and abroad.

Funding is provided by the National Science Foundation (NSF).

"By searching for the same constellations in their respective hemispheres, participants in the Great World Wide Star Count will be able to compare their observations with what others see, giving them a sense of how star visibility varies from place to place," said Cliff Jacobs, program director in NSF's Division of Atmospheric Sciences.

The observers will also learn more about the economic and geographic factors that control light pollution in their communities and around the world.

"The star count brings families together to enjoy the night sky and become involved in science," says Dennis Ward of UCAR's Office of Education and Outreach. "It also raises awareness about the impact of artificial lighting on our ability to see the stars"......... Posted by: Sean      Read more         Source

October 15, 2008, 5:30 PM CT

Ghostly glow reveals galaxy clusters in collision

A team of scientists, including astronomers from the Naval Research Laboratory (NRL), have detected long wavelength radio emission from a colliding, massive galaxy cluster which, surprisingly, is not detected at the shorter wavelengths typically seen in these objects.

The discovery implies that existing radio telescopes have missed a large population of these colliding objects. It also provides an important confirmation of the theoretical prediction that colliding galaxy clusters accelerate electrons and other particles to very high energies through the process of turbulent waves. The team revealed their findings in the October 16, 2008 edition of Nature

This new population of objects is most easily detected at long wavelengths. Professor Greg Taylor of the University of New Mexico and scientific director of the Long Wavelength Array (LWA) points out, "This result is just the tip of the iceberg. When an emerging suite of much more powerful low frequency telescopes, including the LWA in New Mexico, turn their views to the cosmos, the sky will 'light up' with hundreds or even thousands of colliding galaxy clusters." NRL has played a key role in promoting the development of this generation of new instruments and is currently involved with the development of the LWA. NRL radio astronomer and LWA Project Scientist Namir Kassim says "Our discovery of a previously hidden class of low frequency cluster-radio sources is especially important since the study of galaxy clusters was a primary motivation for development of the LWA."........ Posted by: Sean      Read more         Source

October 7, 2008, 10:55 PM CT

Stars stop forming when big galaxies collide

New Haven, Conn. Astronomers studying new images of a nearby galaxy cluster have found evidence that high-speed collisions between large elliptical galaxies may prevent new stars from forming, as per a paper would be published in a November 2008 issue of The Astrophysical Journal Letters

Led by Jeffrey Kenney, professor and chair of astronomy at Yale, the team saw a spectacular complex of warm gas filaments 400,000 light-years-long connecting the elliptical galaxy M86 and the spiral galaxy NGC 4438 in the Virgo galaxy cluster, providing striking evidence for a previously unsuspected high-speed collision between the galaxies. The view was constructed using the wide-field Mosaic imager on the National Science Foundation telescope at Kitt Peak National Observatory near Tucson, Arizona.

"Our data show that this system represents the nearest recent collision between a large elliptical galaxy and a large spiral galaxy," said Kenney, who is lead author of the paper. "This discovery provides some of the clearest evidence yet for high-speed collisions between large galaxies, and it suggests a plausible alternative to black holes as an explanation of what turns off star formation in the biggest galaxies".

Previously, researchers had seen the filaments of gas around both galaxies, but had not seen or inferred any correlation between the two galaxies located approximately 50 million light-years from Earth. The new image shows extended and faint emissions that directly connect the two galaxies and there are no obvious stars in the filaments......... Posted by: Sean      Read more         Source

October 1, 2008, 9:37 PM CT

Infrared Echoes Give NASA's Spitzer a Supernova Flashback

Hot spots near the shattered remains of an exploded star are echoing the blast's first moments, say researchers using data from NASA's Spitzer Space Telescope.

Eli Dwek of NASA's Goddard Space Flight Center in Greenbelt, Md., and Richard Arendt of the University of Maryland, Baltimore County, say these echoes are powered by radiation from the supernova shock wave that blew the star apart some 11,000 years ago. "We're seeing the supernova's first flash," Dwek says.

Other Spitzer scientists discovered hot spots near the Cassiopeia A supernova remnant and recognized their importance as light echoes of the original blast. Dwek and Arendt used Spitzer data to probe this hot dust and pin down the cause of the echoes more precisely.

Six knots of silicate dust near the remnant show temperatures between -280 degrees and -190 degrees Fahrenheit. Eventhough this might seem frigid by Earthly standards, such temperatures are downright hot in comparison to typical interstellar dust.

Writing in the October 1 issue of The Astrophysical Journal, the researchers show that the only event that could make the grains this hot is the powerful and short-lived pulse of ultraviolet radiation and X-rays that heralded the death of the star. The flash was a hundred billion times brighter than the sun but lasted only a day or so......... Posted by: Sean      Read more         Source