Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Astronomers Discover Cold, Warm and Hot Gas Around a Young Brown Dwarf

11.01.2005


A team of scientists from the University of Delaware has discovered that brown dwarfs--celestial bodies that are often referred to as failed stars--can be surrounded by clouds of very hot and very cool gas.



The UD research team of John E. Gizis, assistant professor of physics and astronomy, Harry L. Shipman, Annie Jump Cannon Chair of Physics and Astronomy, and James A. “Rusty” Harvin, researcher in physics and astronomy, used the Hubble Space Telescope to show for the first time that a brown dwarf was associated with a cloud or disk containing molecular hydrogen gas.

The team members presented their results in a poster session dedicated to the study of brown dwarfs and exoplanets and at a news conference held Monday, Jan. 10, during a meeting of the American Astronomical Society in San Diego, Calif.


The UD researchers studied the space object that goes by the name of 2MASSW J1207334-393254, or simply 1207, for the past year. The object is located in the constellation of the Centaur but is so small and dim that it is impossible to see with the unaided eye or even with a pair of binoculars.

The team obtained ultraviolet light observations from a piece of equipment on the Hubble Space Telescope known as the Space Telescope Imaging Spectrograph, or STIS, which failed just weeks after the observations were made.

The team’s most interesting finding was that this brown dwarf was surrounded by a cloud of cold gas containing the common element hydrogen in molecular form. The fingerprints of molecular hydrogen are concentrations of ultraviolet emissions at particular wavelengths, in this case 1503 and 1530 Angstroms.

Hydrogen molecules had previously been found around very young stars but never before in a brown dwarf. "It’s really amazing that the gas around this tiny brown dwarf is behaving so much like the gas around much more massive newly forming stars, called T Tau stars," Gizis said.

Also noteworthy was the finding of other ultraviolet fingerprints from very hot gas. "This star, in the ultraviolet, looks much like bigger and hotter stars like our sun," Shipman said. “Our own sun is surrounded by a layer of warm gas, called the chromosphere, and a layer of very hot gas, called the corona. A thin layer of hot gas, with temperatures of a hundred thousand degrees, separates the two. The brown dwarf 1207 has warm gas and the hot hundred thousand-degree gas. So far, no one has detected the very hot gas in any possible corona around 1207.”

An interesting characteristic of the spectrum is the absence of the chemical element silicon. Most stars that show evidence of hot gas also show signs of familiar chemical elements like carbon, nitrogen and oxygen, all of which are seen in the ultraviolet light from 1207. But, these other stars also show silicon, which Shipman said is absent in the ultraviolet light from 1207. "A likely place for the silicon is in a dusty disk," Shipman said, because the dust would contain a lot of silicon, just like rocks on Earth.

The team would like to look for similar clouds of hot and cool gas around other brown dwarfs, but it will have to wait for successful STIS repair missions. The proposed repair missions would include installation of the Cosmic Origins Spectrograph, or COS, on the Hubble, which could do the additional observations.

"We had this door opened, showing us some wonderful things happening around a young brown dwarf, but then with the failure of STIS and the uncertainty about repair missions, the door was closed again," Gizis said.

Brown dwarfs are larger than planets like Jupiter and smaller than stars. Stars, which are at least 70 times as massive as Jupiter, shine because of self-sustaining nuclear reactions in their cores. When gravity forces young brown dwarfs like 1207 to contract, their insides heat up and they glow, allowing observers to detect them.

The visible light from 1207 indicates that it is fairly hot for a brown dwarf, with a temperature around 2500 degrees, Shipman said. Its presence in a young star-forming region indicates that it is only about 10 million years old, a newborn baby in astronomical terms.

The UD team’s work is supported by the National Aeronautics and Space Administration (NASA) and by the National Science Foundation.

| newswise
Further information:
http://www.udel.edu

More articles from Physics and Astronomy:

nachricht Tiny lasers from a gallery of whispers
20.09.2017 | American Institute of Physics

nachricht New quantum phenomena in graphene superlattices
19.09.2017 | Graphene Flagship

All articles from Physics and Astronomy >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Tiny lasers from a gallery of whispers

New technique promises tunable laser devices

Whispering gallery mode (WGM) resonators are used to make tiny micro-lasers, sensors, switches, routers and other devices. These tiny structures rely on a...

Im Focus: Ultrafast snapshots of relaxing electrons in solids

Using ultrafast flashes of laser and x-ray radiation, scientists at the Max Planck Institute of Quantum Optics (Garching, Germany) took snapshots of the briefest electron motion inside a solid material to date. The electron motion lasted only 750 billionths of the billionth of a second before it fainted, setting a new record of human capability to capture ultrafast processes inside solids!

When x-rays shine onto solid materials or large molecules, an electron is pushed away from its original place near the nucleus of the atom, leaving a hole...

Im Focus: Quantum Sensors Decipher Magnetic Ordering in a New Semiconducting Material

For the first time, physicists have successfully imaged spiral magnetic ordering in a multiferroic material. These materials are considered highly promising candidates for future data storage media. The researchers were able to prove their findings using unique quantum sensors that were developed at Basel University and that can analyze electromagnetic fields on the nanometer scale. The results – obtained by scientists from the University of Basel’s Department of Physics, the Swiss Nanoscience Institute, the University of Montpellier and several laboratories from University Paris-Saclay – were recently published in the journal Nature.

Multiferroics are materials that simultaneously react to electric and magnetic fields. These two properties are rarely found together, and their combined...

Im Focus: Fast, convenient & standardized: New lab innovation for automated tissue engineering & drug

MBM ScienceBridge GmbH successfully negotiated a license agreement between University Medical Center Göttingen (UMG) and the biotech company Tissue Systems Holding GmbH about commercial use of a multi-well tissue plate for automated and reliable tissue engineering & drug testing.

MBM ScienceBridge GmbH successfully negotiated a license agreement between University Medical Center Göttingen (UMG) and the biotech company Tissue Systems...

Im Focus: Silencing bacteria

HZI researchers pave the way for new agents that render hospital pathogens mute

Pathogenic bacteria are becoming resistant to common antibiotics to an ever increasing degree. One of the most difficult germs is Pseudomonas aeruginosa, a...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

“Lasers in Composites Symposium” in Aachen – from Science to Application

19.09.2017 | Event News

I-ESA 2018 – Call for Papers

12.09.2017 | Event News

EMBO at Basel Life, a new conference on current and emerging life science research

06.09.2017 | Event News

 
Latest News

Molecular Force Sensors

20.09.2017 | Life Sciences

Producing electricity during flight

20.09.2017 | Power and Electrical Engineering

Tiny lasers from a gallery of whispers

20.09.2017 | Physics and Astronomy

VideoLinks
B2B-VideoLinks
More VideoLinks >>>