Science Fair Project Encyclopedia
Gliese 876
Gliese 876 is a red dwarf star (spectral type M4V) 15 light years from Earth in the constellation of Aquarius. It is only half the size of our Sun but it has been found to be orbited by at least two large planets which are locked in a 2:1 orbital resonance. It is so far one of only two red dwarfs with known extrasolar planets, the other being GJ 436.
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Planets
Gliese 876 c
Gliese 876 c is a gas giant half the size of Jupiter, discovered in 2001. It orbits within the star's habitability zone, a region in which the temperature is right for water to be liquid. This means that the planet itself would be partly made up of water clouds. In addition, if the planet has any large moons with atmospheres, life might have the potential to develop on them.
Gliese 876 b
| Orbital Elements | |
|---|---|
| Semi-Major Axis (a) | 0.21 AU |
| Eccentricity (e) | 0.10 |
| Orbital Period (P) | 60.02 d |
| Inclination (i) | 84 ± 6° |
| Longitude of Periastron (ϖ) | 333° |
| Time of Periastron (τ) | 2450106.2 JD |
| Physical Characteristics | |
| Mass | 1.89 ± 0.34 MJ |
| Radius | ? RJ |
| Density | ? kg/m³ |
| Temperature | ? K |
| Discovery | |
| Discoverers | Butler, Marcy, Mayor, Queloz |
| Discovery Date | 1999 |
Gliese 876 b is a gas giant twice the size of Jupiter. Its orbit sometimes brings it within the outer edges of the star's habitability zone, but water would normally be frozen on the surface of its moons.
See also
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