GJ 436
| Epoch 2000 | |
|---|---|
| Constellation | Leo |
| Right Ascension | 11h 42m 11.09s |
| Declination | +26° 42' 23.65" |
| Distance | 33.48 ly (10.27 pc) |
| Spectral Type | M2.5 |
| Apparent Magnitude | 10.68 |
| Other Designations | Ross 905, HIP 57087 |
GJ 436 (Gliese-Jahreiss 436), is a dim 11th magnitude red dwarf star about 30 light years from Earth in the constellation of Leo. It is orbited by a recently discovered planet.
GJ 436 b
| Orbital elements | |
|---|---|
| Semi-major axis (a) | 0.0278 AU |
| Eccentricity (e) | 0.12 ± 0.06 |
| Orbital period (P) | 2.6441 ± 0.0005 d |
| Inclination (i) | ?° |
| Longitude of periastron (ϖ) | 332 ± 11° |
| Time of periastron (τ) | 2,451,551.507 ± 0.03 JD |
| Physical characteristics | |
| Mass | >0.067 ± 0.007 MJ |
| Radius | ? RJ |
| Density | ? kg/m³ |
| Temperature | ? K |
| Discovery | |
| Discoverers | Butler, Vogt, Marcy et al. |
| Discovery date | 2004 |
The planet, GJ 436 b was discovered orbiting the star in 2004. It has a similar mass to Neptune, but orbits very close to the star and may not be a small gas giant but a very massive terrestrial planet instead. It is one of the smallest extrasolar planets discovered so far. One orbit around the star takes only about 2 days 15.5 hours. The planet's surface temperature is high, but not as high as other planets in similar orbits because the star is so dim and cool.
External links
- SIMBAD entry
- The Extrasolar Planets Encyclopaedia entry
- Scientists discover first of a new class of extrasolar planets – NASA Press Release (August 13, 2004)