Free Newsletters - Space - Defense - Environment - Energy - Solar - Nuclear
..
. 24/7 Space News .




STELLAR CHEMISTRY
Astronomers Find The Two Dimmest Stellar Bulbs
by Staff Writers
Pasadena CA (SPX) Dec 11, 2008


This artist's concept shows the dimmest star-like bodies currently known - twin brown dwarfs referred to as 2M 0939. The twins, which are about the same size, are drawn as if they were viewed close to one of the bodies. Brown dwarfs are neither planets nor stars. They form like stars out of collapsing clouds of gas and dust, but they don't have enough mass to ignite nuclear burning in their cores and become full-blown stars. They are similar to Jupiter in that they are cool balls of gas, but they are warmer and heavier. Astronomers say that the universe is littered with these cosmic misfits, but because they are so dim, they are hard to find.Image credit: NASA/JPL-Caltech

It's a tie! The new record-holder for dimmest known star-like object in the universe goes to twin "failed" stars, or brown dwarfs, each of which shines feebly with only one millionth the light of our sun.

Previously, astronomers thought the pair of dim bulbs was just one typical, faint brown dwarf with no record-smashing titles. But when NASA's Spitzer Space Telescope observed the brown dwarf with its heat-seeking infrared vision, it was able to accurately measure the object's extreme faintness and low temperature for the first time. What's more, the Spitzer data revealed the brown dwarf is, in fact, twins.

"Both of these objects are the first to break the barrier of one millionth the total light-emitting power of the sun," said Adam Burgasser of the Massachusetts Institute of Technology, Cambridge. Burgasser is lead author of a new paper about the discovery appearing in the Astrophysical Journal Letters.

Brown dwarfs are the misfits of the cosmos. They are compact balls of gas floating freely in space, but they are too cool and lightweight to be stars, and too warm and massive to be planets. The name "brown dwarf" comes from the fact that these small, star-like bodies change color over time as they cool, and thus have no definitive color.

In reality, most brown dwarfs would appear reddish if they could be seen with the naked eye. Their feeble light output also means they are hard to find. The first brown dwarf wasn't discovered until 1995. While hundreds are known today, astronomers say there are many more in space still waiting to be discovered.

The newfound dim duo of brown dwarfs, while notable for their exceptional faintness, will probably not be remembered for their name. They are called 2MASS J09393548-2448279 after the Two Micron All-Sky Survey, or "2MASS," the mission partially funded by NASA that first detected the object in 1999.

Astronomers recently used Spitzer's ultrasensitive infrared vision to learn more about the object, which was still thought to be a solo brown dwarf. These data revealed a warm atmospheric temperature of 565 to 635 Kelvin (560 to 680 degrees Fahrenheit).

While this is hundreds of degrees hotter than Jupiter, it's still downright cold as far as stars go. In fact, 2MASS J09393548-2448279, or 2M 0939 for short, is one of the coldest star-like bodies measured so far.

To calculate the object's brightness, the researchers had to first determine its distance from Earth. After three years of precise measurements with the Anglo-Australian Observatory in Australia, they concluded that 2M 0939 is the fifth-closest known brown dwarf to us, 17 light-years away toward the constellation Antlia. This distance, together with Spitzer's measurements, told the astronomers the object was both cool and extremely dim.

But something was puzzling. The brightness of the object was twice what would be expected for a brown dwarf with its particular temperature.

The solution? The object must have twice the surface area. In other words, it's twins, with each body shining only half as bright, and each with a mass of 30 to 40 times that of Jupiter. Both bodies are one million times fainter than the sun in total light, and at least one billion times fainter in visible light alone.

"These brown dwarfs are the lowest power stellar light bulbs in the sky that we know of," said Burgasser. "And like low-energy fluorescent light bulbs, they emit most of their light in a narrow range of wavelengths, in this case in the infrared."

According to the authors, there are even dimmer brown dwarfs scattered throughout the universe, most too faint to see with current sky surveys. NASA's upcoming Wide-Field Infrared Survey Explorer mission will scan the entire sky at infrared wavelengths, and is expected to uncover hundreds of these inconspicuous characters.

"The holy grail in the study of brown dwarfs is to find out how low you can go in terms of temperature, mass and brightness," said Davy Kirkpatrick, a co-author of the paper at NASA's Infrared Processing and Analysis Center at the California Institute of Technology, Pasadena.

"This will tell us more about how brown dwarfs form and evolve."

Other authors of this paper are Chris Tinney of the University of New South Wales, Australia; Michael C. Cushing of the University of Hawaii, Manoa; Didier Saumon of the Los Alamos National Laboratory, NM; Mark S. Marley, NASA Ames Research Center, Moffett Field, Calif.; and Clara S. Bennett of the Massachusetts Institute of Technology.

.


Related Links
Spitzer
Stellar Chemistry, The Universe And All Within It






Comment on this article via your Facebook, Yahoo, AOL, Hotmail login.

Share this article via these popular social media networks
del.icio.usdel.icio.us DiggDigg RedditReddit GoogleGoogle




Memory Foam Mattress Review
Newsletters :: SpaceDaily :: SpaceWar :: TerraDaily :: Energy Daily
XML Feeds :: Space News :: Earth News :: War News :: Solar Energy News





STELLAR CHEMISTRY
Rivers Of Gas Flow Around Stars
Los Angeles CA (SPX) Dec 09, 2008
A new image from NASA's Spitzer Space Telescope shows a turbulent star-forming region, where rivers of gas and stellar winds are eroding thickets of dusty material. The picture provides some of the best examples yet of the ripples of gas, or bow shocks, that can form around stars in choppy cosmic waters. "The stars are like rocks in a rushing river," said Matt Povich of the Universit ... read more


STELLAR CHEMISTRY
Biggest Full Moon Of The Year

China's First Moon Probe Lowers Orbit For Further Exploration

Goodyear And NASA Successfully Recreate Original Moon Tire

India Can Send Manned Mission To Moon By 2020

STELLAR CHEMISTRY
HiRISE Camera Captures High-Resolution 3D Images Of Mars

China To Launch Probe To Mars With Russian Help In 2009

China To Launch Probe To Mars With Russian Help In 2009

ESA Presents European Participants In Mars500 Isolation Study

STELLAR CHEMISTRY
Space Mission Commander Gives Clues On First Hong Kong Astronaut

India, Russia sign nuclear energy, space deals

Teddy take-off: bears launched into space

Space Mission Commander Gives Clues On First Hong Kong Astronaut

STELLAR CHEMISTRY
HK, Macao Scientists Expected To Participate In China's Aerospace Project

China's Future Astronauts Will Be Scientists

China Launches Remote Sensing Satellite

Damaged Nigerian satellite can't be recovered: officials

STELLAR CHEMISTRY
A Station Celebration

NASA Signs Modification To Contract With Russian Space Agency

New Russian Space Freighter Docks With World Orbital Station

ESA wants International Space Station to live longer

STELLAR CHEMISTRY
Proton-M Rocket With Canadian Commsat Launched From Baikonur

Ciel Satellite Group Spacecraft Ready For Launch

Launch Of Ariane 5 Rocket From Kourou Postponed

Arianespace To Launch ViaSat-1

STELLAR CHEMISTRY
Ball Aerospace Completes Environmental Testing For Kepler Mission

Predicted Planet Seen - First Since Neptune 162 Years Ago

Hubble telescope finds carbon dioxide on distant planet

Hubble Finds Carbon Dioxide On An Extrasolar Planet

STELLAR CHEMISTRY
HP offering aims at penny-pinching IT departments

First Muslim-friendly virtual world goes online

Computer industry celebrates 40 years

Space Foundation Recognizes Three GMV Products As Certified Space Technologies




The content herein, unless otherwise known to be public domain, are Copyright 1995-2014 - Space Media Network. AFP, UPI and IANS news wire stories are copyright Agence France-Presse, United Press International and Indo-Asia News Service. ESA Portal Reports are copyright European Space Agency. All NASA sourced material is public domain. Additional copyrights may apply in whole or part to other bona fide parties. Advertising does not imply endorsement,agreement or approval of any opinions, statements or information provided by Space Media Network on any Web page published or hosted by Space Media Network. Privacy Statement