BD+20°1790
| Observation data Epoch J2000.0 Equinox J2000.0 |
|
|---|---|
| Constellation | Gemini |
| Right ascension | 07h 23m 43.592s |
| Declination | +20° 24′ 58.66″ |
| Apparent magnitude (V) | 9.93 |
| Characteristics | |
| Spectral type | K5Ve[1] |
| Apparent magnitude (B) | 11.08 |
| Apparent magnitude (R) | 9.43 |
| Apparent magnitude (I) | 8.9 |
| Apparent magnitude (J) | 7.643 |
| Apparent magnitude (H) | 7.032 |
| Apparent magnitude (K) | 6.879 |
| B−V color index | 1.15 |
| V−R color index | 0.50 |
| R−I color index | 0.5 |
| Astrometry | |
| Radial velocity (Rv) | +9.3 km/s |
| Proper motion (μ) | RA: −65.8 mas/yr Dec.: −228.1 mas/yr |
| Distance | 84.76 ly (26[1] pc) |
| Absolute magnitude (MV) | 7.86 |
| Details | |
| Mass | 0.63[2] M☉ |
| Radius | 0.71[2] R☉ |
| Luminosity | 0.17[2] L☉ |
| Surface gravity (log g) | 4.53[2] cgs |
| Temperature | 4410[2] K |
| Metallicity | 0.30[2] |
| Rotation | 3.59 days |
| Rotational velocity (v sin i) | 10.03[2] km/s |
| Age | 35-80[2][3]million years |
| Other designations | |
| Database references | |
| SIMBAD | data |
| Exoplanet Archive | data |
| Extrasolar Planets Encyclopaedia |
data |
BD+20°1790 is a young late orange dwarf star in the constellation Gemini, located nearly 85 light years away from the Sun. The star is young and very active and is a member of the AB Doradus Moving Group.[4] The star has also been studied and monitored by SuperWASP group and found to coincide with the ROSAT source 1RXS J072343.6+202500.[5] The planet candidate was announced in December 2009.[2]
Disproven planet
The Keplerian fit of the RV data suggested an orbital solution for a close-in massive planet with an orbital period of 7.7834 days. Moreover, the presence of a close-in massive jovian planet could explain the high level of stellar activity detected.[2] However, further study suggests that this planet may not exist because the radial velocity variations are strongly correlated to stellar activity, suggesting this activity is the cause of the variations.[6] This echoes the similar case of the disproven planet detection around TW Hydrae, which was also found to be due to stellar activity rather than orbital motion.[7]
References
- ↑ 1.0 1.1 Lua error in package.lua at line 80: module 'strict' not found.
- ↑ 2.0 2.1 2.2 2.3 2.4 2.5 2.6 2.7 2.8 2.9 Lua error in package.lua at line 80: module 'strict' not found.
- ↑ Lua error in package.lua at line 80: module 'strict' not found.
- ↑ Lua error in package.lua at line 80: module 'strict' not found.
- ↑ Lua error in package.lua at line 80: module 'strict' not found.
- ↑ Lua error in package.lua at line 80: module 'strict' not found.
- ↑ Lua error in package.lua at line 80: module 'strict' not found.
See also
Coordinates: 
07h 23m 44s, +20° 24′ 51″
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