Huge Planet Defies Explanation
Date: Tuesday, October 07th, 2008 (CST )
Topic: Cosmology & Astronomy
 Astronomers have sighted a very dense planet-sized object that orbits its parent star in just four days and six hours. The object, COROT-exo-3b, fits into the category of a failed star known as a brown dwarf, but the team that made the discovery has not ruled out the possibility that it is a planet. Brown dwarfs are failed stars. They burn lithium but are not massive enough to generate the thermonuclear fusion of hydrogen and helium that powers real stars. Planets do none of that.
"It has puzzled us; we're not sure where to draw the boundary between planets and brown dwarfs," said Hans Deeg, an astronomer at the Instituto de Astrofisica de Canarias (IAC) in the Canary Islands, Spain.
The object has a mass 20 times greater than that of Jupiter, but is roughly the same size. It falls outside the range of planets and stars discovered to date, with the largest planets having 12-Jupiter-mass and the smallest stars 70-Jupiter-mass.
If
astronomers confirm the object as a planet, it would weigh in as the
most massive and densest planet found so far. A full study will be
detailed in the journal Astronomy and Astrophysics.
"COROT-exo-3b might turn
out to be a rare object found by sheer luck", said Francois Bouchy, an
astronomer at the Institut d'Astrophysique in Paris. "But it might just
be a member of a new-found family of very massive planets that encircle
stars more massive than our sun. We're now beginning to think that the
more massive the star, the more massive the planet."
Ground-based telescopes
around the world helped pinpoint the object, including observatories in
France, Chile, Germany, Hawaii, Israel and Spain's Canary Islands.
The hunt for exoplanets has
intensified over recent years, with astronomers usually finding such
objects indirectly by observing their gravitational influence on parent
stars. Another team showcased what might be the first direct image of
an exoplanet around a sun-like star in September.
Copyright: Yahoo! News
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