Astronomy:HD 22781
| Observation data Equinox J2000.0]] (ICRS) | |
|---|---|
| Constellation | Perseus[1] |
| Right ascension | 03h 40m 49.5246s[2] |
| Declination | +31° 49′ 34.6489″[2] |
| Apparent magnitude (V) | 8.78[3] |
| Characteristics | |
| Evolutionary stage | main-sequence star[4] |
| Spectral type | K0[3] |
| Astrometry | |
| Radial velocity (Rv) | 8.26[2] km/s |
| Proper motion (μ) | RA: 40.576[2] mas/yr Dec.: −94.254[2] mas/yr |
| Parallax (π) | 30.6433 ± 0.1071[5] mas |
| Distance | 106.4 ± 0.4 ly (32.6 ± 0.1 pc) |
| Absolute magnitude (MV) | +6.21[1] |
| Details[6] | |
| Mass | 0.75±0.02 M☉ |
| Radius | 0.70±0.02 R☉ |
| Surface gravity (log g) | 4.57±0.04 cgs |
| Temperature | 5175±15 K |
| Metallicity [Fe/H] | −0.35±0.02 dex |
| Rotational velocity (v sin i) | 1.73[4] km/s |
| Age | 4.14±3.63 Gyr |
| Other designations | |
| Database references | |
| SIMBAD | data |
HD 22781, is a single star about 106 light-years away. It is a K-type main-sequence star. The star’s age is poorly constrained at 4.14±3.63 billion years, but is likely similar to that of the Sun.[6] HD 22781 is heavily depleted in heavy elements, having just 45% of Sun's concentration of iron,[3] yet is comparatively rich in carbon, having 90% of Sun's abundance.[6]
An imaging survey in 2012 has failed to find any stellar companions, suggesting HD 22781 is a single star.[7]
Planetary system
In 2011 a transiting superjovian planet or brown dwarf b was detected on an extremely eccentric orbit.[4] It is located just outside of the conservative habitable zone of the parent star.[8] Planets around such metal-poor stars are rare; the only three known similar cases are HD 111232 and HD 181720.[9]
In 2012, a radial velocity data review indicated there are no additional giant planets in the system.[10]
| Companion (in order from star) |
Mass | Semimajor axis (AU) |
Orbital period (days) |
Eccentricity | Inclination | Radius |
|---|---|---|---|---|---|---|
| b | ≥13.65±0.97 MJ | 1.167±0.039 | 528.07±0.14 | 0.8191±0.0023 | — | — |
References
- ↑ 1.0 1.1 Anderson, E.; Francis, Ch. (2012). "XHIP: An extended hipparcos compilation". Astronomy Letters 38 (5): 331. doi:10.1134/S1063773712050015. Bibcode: 2012AstL...38..331A XHIP record for this object at VizieR.
- ↑ 2.0 2.1 2.2 2.3 2.4 2.5 "HD 22781". SIMBAD. Centre de données astronomiques de Strasbourg. http://simbad.u-strasbg.fr/simbad/sim-basic?Ident=HD+22781.
- ↑ 3.0 3.1 3.2 Maldonado, J.; Villaver, E.; Eiroa, C.; Micela, G. (2019), "Connecting substellar and stellar formation. The role of the host star's metallicity", Astronomy & Astrophysics 624: A94, doi:10.1051/0004-6361/201833827, Bibcode: 2019A&A...624A..94M
- ↑ 4.0 4.1 4.2 4.3 Díaz, Rodrigo F.; Santerne, Alexandre; Sahlmann, Johannes; Hébrard, Guillaume; Eggenberger, Anne; Santos, Nuno C.; Moutou, Claire; Arnold, Luc et al. (2012), "The SOPHIE search for northern extrasolar planets IV. Massive companions in the planet-brown dwarf boundary", Astronomy & Astrophysics A113: 538, doi:10.1051/0004-6361/201117935, Bibcode: 2012A&A...538A.113D
- ↑ Brown, A. G. A. (August 2018). "Gaia Data Release 2: Summary of the contents and survey properties". Astronomy & Astrophysics 616: A1. doi:10.1051/0004-6361/201833051. Bibcode: 2018A&A...616A...1G. Gaia DR2 record for this source at VizieR.
- ↑ 6.0 6.1 6.2 Maldonado, J.; Villaver, E. (2017), "Searching for chemical signatures of brown dwarf formation", Astronomy & Astrophysics 602: A38, doi:10.1051/0004-6361/201630120, Bibcode: 2017A&A...602A..38M
- ↑ Ginski, C.; Mugrauer, M.; Seeliger, M.; Eisenbeiss, T. (2012), "A lucky imaging multiplicity study of exoplanet host stars", Monthly Notices of the Royal Astronomical Society 421 (3): 2498–2509, doi:10.1111/j.1365-2966.2012.20485.x, Bibcode: 2012MNRAS.421.2498G
- ↑ Agnew, Matthew T.; Maddison, Sarah T.; Thilliez, Elodie; Horner, Jonathan (2017), "Stable habitable zones of single Jovian planet systems", Monthly Notices of the Royal Astronomical Society 471 (4): 4494–4507, doi:10.1093/mnras/stx1449, Bibcode: 2017MNRAS.471.4494A
- ↑ Adibekyan, Vardan (2019), "Heavy Metal Rules. I. Exoplanet Incidence and Metallicity", Geosciences 9 (3): 105, doi:10.3390/geosciences9030105, Bibcode: 2019Geosc...9..105A
- ↑ Wittenmyer, Robert A.; Wang, Songhu; Horner, Jonathan; Tinney, C. G.; Butler, R. P.; Jones, H. R. A.; O'Toole, S. J.; Bailey, J. et al. (2013), "Forever alone? Testing single eccentric planetary systems for multiple companions", The Astrophysical Journal Supplement Series 208 (1): 2, doi:10.1088/0067-0049/208/1/2, Bibcode: 2013ApJS..208....2W
Coordinates: 
03h 40m 49.5246s, +31° 49′ 34.6489″
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