Brown Dwarfs -New Link between Stars & Planets Discovered
A cold brown about 40 light-years from our solar system might represent a new class of objects that are a missing link between planets and stars.
The spent star floats freely in space, not bound to a star. Its mass is somewhere between 15 and 30 times that of Jupiter. And it is about 660 degrees Fahrenheit (350 Celsius), cooler than any other known object in its class. The mass of brown dwarfs is usually less than 70 Jupiter masses. A brown dwarf spends its lifetime getting colder and colder in contrast to a star like our sun, which spends most of its lifetime burning hydrogen and keeping a constant internal temperature,
The brown dwarf, named , was found by an international team using
the Canada France Hawaii Telescope and Gemini North Telescope, both
located in Hawaii, and the a European Southern Observatory telescope in
Chile.
The newly-discovered brown dwarf, CFBDS
J005910.83-011401.3, looks much more like a giant planet than the known
classes of brown dwarfs, both because of its low temperature and
because of the presence of ammonia.
To date, two classes of
brown dwarfs have been known: the L dwarfs (temperature of 2,100 to
3,600 Fahrenheit (1,200-2,000 C), which have clouds of dust and
aerosols in their high atmosphere, and the T dwarfs (temperature lower
than 2,100 F), which have a very different spectrum because of methane
forming in their atmosphere.
Because it contains ammonia and has
a much lower temperature than do L and T dwarfs, CFBDS0059 might be the
protoype of a new class of brown dwarfs to be called the Y dwarfs, the
researchers propose. This new class would become the coldest stellar
objects, a missing link toward giant planets.
The discovery, led
by researchers at Observatoire de Grenoble in France, the Canada France
Hawaii Telescope, the University of Ottowa and other institutions will
be detailed in the journal Astronomy & Astrophysics.
Posted by Jason McManus.
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