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Revision as of 01:44, 18 September 2020 by Trurle (talk | contribs) (→Planetary system: fixing bad refs, lead section)(diff) ← Previous revision | Latest revision (diff) | Newer revision → (diff)| Observation data Epoch J2000.0 Equinox J2000.0 | |
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| Constellation | Fornax |
| Right ascension | 03 20 02.943 |
| Declination | –28° 47′ 01.80″ |
| Apparent magnitude (V) | 8.48 |
| Characteristics | |
| Spectral type | K0V |
| B−V color index | 0.82 |
| Astrometry | |
| Proper motion (μ) | RA: 348.97 ± 0.71 mas/yr Dec.: –67.69 ± 0.91 mas/yr |
| Parallax (π) | 28.27 ± 1.08 mas |
| Distance | 115 ± 4 ly (35 ± 1 pc) |
| Details | |
| Mass | 0.7 M☉ |
| Luminosity | 0.49±0.04 L☉ |
| Surface gravity (log g) | 4.37±0.05 cgs |
| Temperature | 5256±29 K |
| Metallicity | −0.11±0.02 dex |
| Rotation | 46.8±4.4 d |
| Rotational velocity (v sin i) | 1.1 km/s |
| Other designations | |
| CD–29° 1229, HIP 15526, LTT 1581, SAO 168468 | |
| Database references | |
| SIMBAD | data |
HD 20781 is a star which is part of a wide binary system with HD 20782. The companion star has a very large angular separation of 252 arcsec, corresponding to 9080 AU at the distance of HD 20782. Both stars possess their own planetary systems in S type orbits. This is the first time that planets have been found in both components of a wide binary system. The HD 20781 do not have a noticeable starspot activity.
Planetary system
In 2011, a pair of small gas giants was detected by radial velocity method. As is 2017, additional two inner rocky planets are suspected, with periods 5.3 and 13.9 days respectively.
| Companion (in order from star) |
Mass | Semimajor axis (AU) |
Orbital period (days) |
Eccentricity | Inclination | Radius |
|---|---|---|---|---|---|---|
| b | >12.04±1.11 M🜨 | 0.169 ± 0.0028 | 29.15 ± 0.0201 | 0.11 ± 0.06 | — | — |
| c | >15.76 ± 1.20 M🜨 | 0.3456 ± 0.0047 | 85.131 ± 0.1161 | 0.28 ± 0.09 | — | — |
See also
- List of extrasolar planets
- XO-2, a wide binary star in the constellation Lynx
References
- Roman, Nancy G. (1987). "Identification of a Constellation From a Position". Publications of the Astronomical Society of the Pacific. 99 (617): 695–699. Bibcode:1987PASP...99..695R. doi:10.1086/132034. Vizier query form
- ^ van Leeuwen, F. (2007). "Validation of the new Hipparcos reduction". Astronomy and Astrophysics. 474 (2): 653–664. arXiv:0708.1752. Bibcode:2007A&A...474..653V. doi:10.1051/0004-6361:20078357.Vizier catalog entry
- ^ The HARPS search for southern extra-solar planets. XLII. Eight HARPS multi-planet systems hosting 20 super-Earth and Neptune-mass companions, 2017, arXiv:1705.05153
- "HD 20781 -- High proper-motion Star". SIMBAD Astronomical Database. Centre de données astronomiques de Strasbourg. Retrieved 2014-09-10.
- ^ Properties of planets in binary systems.
- Cite error: The named reference
Sch-20781was invoked but never defined (see the help page). - Mayor, M. Marmier,M. Lovis,C. Udry,S. Ségransan,D. Pepe,F. Benz,W. Bertaux,J.-L. Bouchy,F. Dumusque, G. Curto,Lo Mordasini,C. Queloz,D. Santos,N. C.; et al. (2011). "The HARPS search for southern extra-solar planets XXXIV. Occurrence, mass distribution and orbital properties of super-Earths and Neptune-mass planets". arXiv:1109.2497 .
{{cite arXiv}}: CS1 maint: multiple names: authors list (link)
External links
- "Planet HD 20781 c". The Extrasolar Planets Encyclopaedia. Retrieved 18 September 2020.
- "Planet HD 20781 b". The Extrasolar Planets Encyclopaedia. Retrieved 18 September 2020.
| The HD 20781/HD 20782 system | |
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| HD 20781 | |
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