| Extrasolar planet | List of extrasolar planets | |
|---|---|---|
| Parent star | ||
| Star | BD+20°2457 | |
| Constellation | Leo | |
| Right ascension | (α) | 10h 16m 44.8635s |
| Declination | (δ) | +19° 53′ 28.974″ |
| Distance | 650 ± 330 ly (200 ± 100 pc) |
|
| Spectral type | K2II | |
| Orbital elements | ||
| Semimajor axis | (a) | 1.45 AU |
| Periastron | (q) | 1.23 AU |
| Apastron | (Q) | 1.67 AU |
| Eccentricity | (e) | 0.15 ± 0.03 |
| Orbital period | (P) | 379.63 ± 2.01 d (1.0394 ± 0.0055 y) |
| Argument of periastron |
(ω) | 207.64 ± 21.99° |
| Time of periastron | (T0) | 54677.03 ± 28.19 JD |
| Semi-amplitude | (K) | ? m/s |
| Physical characteristics | ||
| Minimum mass | (m sin i) | 21.42 MJ |
| Discovery information | ||
| Discovery date | June 10, 2009 | |
| Discoverer(s) | Niedzielski et al. | |
| Detection method | radial velocity | |
| Discovery site | La Silla Observatory | |
| Discovery status | Published | |
| Database references | ||
| Extrasolar Planets Encyclopaedia |
data | |
| SIMBAD | data | |
BD+20°2457 b is a brown dwarf located between 320 to 980 light years away in the constellation of Leo, orbiting the 10th magnitude K-type bright giant star BD+20°2457. It has mass 21.42 times more massive than Jupiter and the orbit takes 4% longer than Earth’s to go around the star. The other companion in this system BD+20°2457 c, is a very massive planet (massing at least 12.47 times greater than Jupiter), meaning it is likely that the other companion may also be a brown dwarf. This brown dwarf was discovered on June 10, 2009, using the Hobby-Eberly Telescope.