Astronomers Measure Precise Mass of a Binary Brown Dwarf

EMBARGOED UNTIL: 1:00 pm (EST) March 15, 2006

Jeff Valenti
Space Telescope Science Institute, Baltimore, Md.
(Phone: 410/338-2622; E-mail: )

Ray Villard
Space Telescope Science Institute, Baltimore, Md.
(Phone: 410/338-4514; E-mail: )

David Salisbury
Vanderbilt University, Nashville, Tenn.
(Phone: 615/343-6803; E-mail: )

Terry Devitt
University of Wisconsin-Madison, Madison, Wis.
(Phone: 608/262-8282; E-mail: )

PRESS RELEASE NO.: STScI-PR06-11

ASTRONOMERS MEASURE PRECISE MASS OF A BINARY BROWN DWARF

Brown dwarfs are mysterious celestial objects that fall somewhere
between the smallest stars and the largest planets. They have always
been viewed by astronomers as a critical link in the understanding of
how both stars and planets form. One problem has been that brown dwarfs
are hard to find and so have defied nearly all attempts to accurately
assess their size. But now astronomers, have discovered a pair of young
brown dwarfs in mutual orbit. This has enabled scientists to weigh and
measure the diameters of brown dwarfs for the first time. The new
observations confirm the theoretical prediction that brown dwarfs start
out as star-sized objects, but shrink and cool and become increasingly
planet sized as they age. Before now, the only brown dwarf whose mass
had been directly measured was much older and dimmer. The discovery of
the paired brown dwarfs and the critical measurements are reported
today
in the scientific journal Nature.

For the full story about this research on Web, visit:
http://hubblesite.org/news/2006/11
http://vanderbilt.edu/news
http://www.vanderbilt.edu/exploratio...rowndwarf.html
http://www.news.wisc.edu

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