First clear evidence for existence of a brown dwarf | 17/11/1995 | ||
![]() |
These two false-color telescope images reveal the faintest object ever seen around a star beyond our Sun, and the first unambiguous detection of a brown dwarf. The brown dwarf, called GL229B, orbits the red dwarf star Gliese 229, located approximately 18 light-years away in the constellation Lepus. | ||
Go to full text | |||
![]() |
|||
![]() |
|||
Image Credit: T. Nakajima & S. Kulkarni (Caltech), S. Durrance & D.Golimowski (JHU), NASA. | |||
|
|||
These
two false-color telescope images reveal the faintest object ever seen around
a star beyond our Sun, and the first unambiguous detection of a brown dwarf.
The brown dwarf, called GL229B, orbits the red dwarf star Gliese 229, located
approximately 18 light-years away in the constellation Lepus. The brown
dwarf is about 20-50 times the mass of Jupiter, but is so dense it is about
the same diameter as Jupiter (80,000 miles).
Brown dwarfs are a mysterious class of long-sought objects that form the same way stars do, by condensing out of a cloud of hydrogen gas. However, they do not accumulate enough mass to sustain nuclear fusion at their core, which make stars shine. [left] - The brown dwarf (center) was first observed in far red light
October 27, 1994 using the adaptive optics device and a 60-inch reflecting
telescope on Palomar Mountain in California. Another year was required
to confirm that the object was actually gravitationally bound to the companion
star. GL229B is at least four billion miles from its companion star, roughly
the separation between the planet Pluto and our Sun. Even though a cornograph
on the detector masked most of the light from the star, which is off the
left edge of the image, it is so bright relative to the brown dwarf the
glare floods the detector. |
![]() |
[right]
- This image of the GL229B (center) was taken with Hubble Space Telescope's
Wide Field Planetary Camera-2, in far red light, on November 17, 1995. The
Hubble observations will be used to accurately measure the brown dwarf's
distance from Earth, and yield preliminary data on its orbital period, which
may eventually offer clues to the dwarf's origin. Though the star Gliese
229 is off the edge of the image, it is so bright it floods Hubble detector.
The diagonal line is a diffraction spike produced by the telescope's optical
system. Credit: S. Kulkarni (Caltech), D.Golimowski (JHU) and NASA |
|
Return to top of page |