Showing posts with label Brown Dwarf. Show all posts
Showing posts with label Brown Dwarf. Show all posts

Monday, December 7, 2009

First Direct Observation of a Planet-Like Object Orbiting Star Similar to Sun


This August 2009 discovery image of GJ 758 B was taken with the Subaru Telescope’s HiCIAO instrument in the near infrared, which measures and records differences in heat. Without the special technique employed here (angular differential imaging), the star’s glare would overwhelm the light from the planet candidates. The planet-like object, GJ 758 B, is circled as B in the lower right portion of the image. An unconfirmed companion planet or planet-like object, C, can be viewed above B. The star, GJ 758, is located at the center of the image, at the hub of the starburst. The graphic at the top compares the orbital distances of solar system planets. (Credit: Max Planck Institute for Astronomy/National Astronomical Observatory of Japan)

An international team of scientists that includes an astronomer from Princeton University has made the first direct observation of a planet-like object orbiting a star similar to the sun.


The finding marks the first discovery made with the world’s newest planet-hunting instrument on the Hawaii-based Subaru Telescope and is the first fruit of a novel research collaboration announced by the University in January.


The object, known as GJ 758 B, could be either a large planet or a “failed star,” also known as a brown dwarf. The faint companion to the sun-like star GJ 758 is estimated to be 10 to 40 times as massive as Jupiter and is a “near neighbor” in our Milky Way galaxy, hovering a mere 300 trillion miles from Earth.


“It’s a groundbreaking find because one of the current goals of astronomy is to directly detect planet-like objects around stars like our sun,” said Michael McElwain, a postdoctoral research fellow in Princeton’s Department of Astrophysical Sciences who was part of the team that made the discovery. “It is also an important verification that the system — the telescope and its instruments — is working well.”


Images of the object were taken in May and August during early test runs of the new observation equipment. The team has members from Princeton, the University of Hawaii, the University of Toronto, the Max Planck Institute for Astronomy (MPIA) in Heidelberg, Germany, and the National Astronomical Observatory of Japan (NAOJ) in Tokyo. The results will be published in the Astrophysical Journal Letters.


“This challenging but beautiful detection of a very low mass companion to a sun-like star reminds us again how little we truly know about the census of gas giant planets and brown dwarfs around nearby stars,” said Alan Boss, an astronomer at the Carnegie Institution for Science in Washington, D.C., who was not involved in the research. “Observations like this will enable theorists to begin to make sense of how this hitherto unseen population of bodies was able to form and evolve.” Full story

Story Source:

http://www.sciencedaily.com/releases/2009/12/091203141909.htm

Adapted from materials provided by Princeton University. Original article written by Kitta MacPherson.


Journal Reference:
  1. Christian Thalmann, Joseph Carson, Markus Janson, Miwa Goto, Michael Mcelwain, Sebastian Egner, Markus Feldt, Jun Hashimoto, Yutaka Hayano, Thomas Henning, Klaus W. Hodapp, Ryo Kandori, Hubert Klahr, Tomoyuki Kudo, Nobuhiko Kusakabe, Christoph Mordasini, Jun-Ichi Morino, Hiroshi Suto, Ryuji Suzuki, Motohide Tamura. Discovery of the Coldest Imaged Companion of a Sun-Like Star. Astrophysical Journal Letters, 2009; (accepted for publication) [link]

http://www.sciencedaily.com/releases/2009/12/091203141909.htm

UniverseToday.com | NASA to Launch WISE (Wide-field Infrared Survey Explorer) on Friday to look for asteroids and brown dwarfs close to home

Cave Editor's Note:
BROWN DWARF

CAUGHT MY EYE SINCE I AM JUST STUDYING SOMETHING FROM A SPANISH ASTRONOMER AND A POTENTIAL BROWN DWARF THAT IS OUR OWN SUN'S BINARY COMPANION OUT BY PLUTO!
(What might be causing the Sun to act weird magnetically)



NASA to Launch WISE on Friday to look for asteroids and brown dwarfs close to home
Universe Today

NASA is getting WISE to the Universe this Friday. That is, they're launching the Wide-field Infrared Survey Explorer, a new infrared space telescope that will survey objects in our Solar System and beyond, looking for asteroids and brown dwarfs close to home, and protoplanetary disks and newborn stars far off.

WISE will also be sensitive enough to pick up brown dwarfs, objects that straddle the line between planet and star. Though they are massive, they don't quite make the cut for igniting nuclear fusion in their cores, but are warm enough to emit infrared light. It's thought that there are quite a few of these objects in our own back yard waiting to be discovered, and WISE may double or triple the amount of star-like objects that are within 25 light-years of the Earth.

Source: http://www.universetoday.com/2009/12/07/nasa-to-launch-wise-on-friday/


RELATED:


http://www.space.com/scienceastronomy/091130-mm-baby-brown-dwarf.html

Clue Found to Origin of Cosmic Misfits

By SPACE.com staff

posted: 30 November 2009
09:42 am ET

A class of cosmic oddballs exists that doesn't fit in with either stars or planets, instead occupying a murky middle ground.


Known as brown dwarfs, these misfits fall somewhere between planets and stars in terms of their temperature and mass. They are cooler and more lightweight than stars and more massive (and normally warmer) than planets.


This has generated a debate among astronomers: Do brown dwarfs form like planets or like stars?


Scientists now have an additional clue – a baby brown dwarf was discovered by NASA's Spitzer Space Telescope – that suggests brown dwarfs develop like light-weight stars.


Brown dwarf quandry


Brown dwarfs are born of the same dense, dusty clouds that spawn stars and planets. But while they may share the same galactic nursery, brown dwarfs are often called "failed" stars because they lack the mass of their hotter, brighter stellar siblings.


Without that mass, the gas at their core does not get hot enough to trigger the thermonuclear fusion that burns hydrogen — the main component of these molecular clouds — into helium. Unable to ignite as stars, brown dwarfs end up as cooler, less luminous objects that are more difficult to detect – a challenge that was overcome in this case by Spitzer's heat-sensitive infrared vision.


To complicate matters, young brown dwarfs evolve rapidly, making it difficult to catch them when they are first born.


The first brown dwarf was discovered in 1995, and while hundreds have been found since, astronomers had not been able to unambiguously find them in their earliest stages of formation until now.


Looking through cosmic dust


In this study, an international team of astronomers found a so-called "proto brown dwarf" while it was still hidden in its natal star-forming region. Guided by Spitzer data collected in 2005, they focused their search in the dark cloud Barnard 213, a region of the Taurus-Auriga complex well known to astronomers as a hunting ground for young cosmic objects.


"We decided to go several steps back in the process when (brown dwarfs) are really hidden," said David Barrado of the Centro de Astrobiologia in Madrid, Spain, lead author of the paper detailing the discovery in the Astronomy & Astrophysics journal. "During this step they would have an (opaque) envelope, a cocoon, and they would be easier to identify due to their strong infrared excesses. We have used this property to identify them. This is where Spitzer plays an important role because Spitzer can have a look inside these clouds."


Spitzer's longer-wavelength infrared camera penetrated the dusty natal cloud to observe a baby brown dwarf named SSTB213 J041757. The data, confirmed with near-infrared imaging from Calar Alto Observatory in Spain, revealed not one but two of what would potentially prove to be the faintest and coolest brown dwarfs ever observed. They're also the youngest, the astronomers think.


To pin down that the dusty envelope was in fact a celestial womb and that these dwarfs were in their infancy, Barrado and his team had them observed from around the world. The information gleaned from these observations helped the astronomers characterize the brown dwarfs and the environment around them.


"We were able to estimate that these two objects are the faintest and coolest discovered so far," Barrado said.


The observations suggest brown dwarfs form like low-mass stars. This theory is bolstered because the change in brightness of the objects at various wavelengths of light matches that of other very young, low-mass stars.


While further study will confirm whether these two celestial objects are in fact proto brown dwarfs, they are the best candidates so far, Barrado said.