HAT-P-20
HAT-P-20 is a K-type main-sequence star about 232 light-years away. The star has a strong starspot activity,[2] and its equatorial plane is misaligned by 36+10
−12° with the planetary orbit.[3] Although star with a giant planet on close orbit is expected to be spun-up by tidal forces, only weak indications of tidal spin-up were detected.[4]
| Observation data Epoch J2000 Equinox J2000 | |
|---|---|
| Constellation | Gemini |
| Right ascension | 07h 27m 39.9487s[1] |
| Declination | +24° 20′ 11.5183″[1] |
| Apparent magnitude (V) | 11.35[1] |
| Characteristics | |
| Spectral type | K3V |
| Astrometry | |
| Radial velocity (Rv) | -18.559 km/s |
| Proper motion (μ) | RA: -4.985 mas/yr Dec.: -96.235 mas/yr |
| Parallax (π) | 14.0483 ± 0.0391[1] mas |
| Distance | 232.2 ± 0.6 ly (71.2 ± 0.2 pc) |
| Details[2][3] | |
| Mass | 0.798±0.018 M☉ |
| Radius | 0.744±0.011 R☉ |
| Surface gravity (log g) | 4.52±0.09 cgs |
| Temperature | 4595±45 K |
| Metallicity | 0.22±0.09 |
| Rotation | 14.66±0.03 d |
| Rotational velocity (v sin i) | 2.0±0.5 km/s |
| Age | 0.8 Gyr |
| Other designations | |
| Database references | |
| SIMBAD | data |
Planetary system
In 2010 a transiting hot super-Jovian planet was detected.[5] Its equilibrium temperature is 996±19 K.
Size comparison of HAT-P-20 b and Jupiter
| Companion (in order from star) |
Mass | Semimajor axis (AU) |
Orbital period (days) |
Eccentricity | Inclination | Radius |
|---|---|---|---|---|---|---|
| b | 7.59±0.12 MJ | 0.03671±0.00027 | 2.8753172±0.0000003 | 0.0172±0.0016 | 86.3±0.1° | 0.952±0.017 RJ |
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References
- HAT-P-20 -- High proper-motion Star
- Leilei Sun, Shenghong Gu, Xiaobin Wang at al., "REFINED SYSTEM PARAMETERS AND TTV STUDY OF TRANSITING EXOPLANETARY SYSTEM HAT-P-20", 2017
- The GAPS Programme with HARPS-N at TNG. XIII. The orbital obliquity of three close-in massive planets hosted by dwarf K-type stars: WASP-43, HAT-P-20 and Qatar-2., 2017, arXiv:1702.03136
- High-energy irradiation and mass loss rates of hot Jupiters in the solar neighborhood, 2015, arXiv:1502.00576
- HAT-P-20b–HAT-P-23b: FOUR MASSIVE TRANSITING EXTRASOLAR PLANETS, 2010, arXiv:1008.3388
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