A red dwarf around which has been found
a planet with about twice the mass of Jupiter. This is the closest known
extrasolar planet to the Sun and the
first to be detected and confirmed in orbit around a dwarf star. Although
Gliese 876b is considerably closer to its primary than Mercury
is to the Sun, it has an estimated surface temperature of only -75°C
due to the red dwarf's low luminosity.
The high mass of Gliese 876b suggests that it is a gas
giant and therefore probably unsuitable, in any case, to terrestrial-type
life. Any large moons that it might have, however, might offer more clement
conditions for life as we know it. The relatively high eccentricity
of the planet's orbit provides another reminder that our own solar system
is not necessarily representative of planetary systems as a whole.
| Gliese 876 (center). Credit: Digitized
| Host star
||15.38 light-years (4.72 pc)
| The Gliese 876 system, as seen from
a hypothetical moon of the outer planet. Artist: Lynette Cook, ©
||0.21 AU (32 million km, 20 million miles)
|Year of discovery
||Marcy et al (SFSU); Delfosse et al (Geneva)
|Method of discovery
- Delfosse, X., Forveille, T., Mayor, M., Perrier, C., Naef, D., and
Queloz, D. "The Closest Extrasolar Planet: A Giant Planet Around the
M4 Dwarf Gl 876," Astronomy & Astrophysics, 338, L67 (1998).
- Marcy, G. W., Butler, R. P., Vogt, S. S., Fischer, D., and Lissauer,
J. "A Planetary Companion to the M4 Red Dwarf, Gliese 876," Astrophysical
Journal Letters, 505, L147 (1998).
PLANETS AND SUBSTELLAR OBJECTS