Astronomy:HIP 12961
| Observation data Equinox J2000.0]] (ICRS) | |
|---|---|
| Constellation | Eridanus |
| Right ascension | 02h 46m 42.89s[1] |
| Declination | −23° 05′ 11.80″[1] |
| Apparent magnitude (V) | 10.24[2] |
| Characteristics | |
| Spectral type | K5V[3] or M0[4] |
| Apparent magnitude (B) | 11.20[2] |
| Apparent magnitude (J) | 7.56[2] |
| Apparent magnitude (H) | 6.93[2] |
| Apparent magnitude (K) | 6.74[2] |
| B−V color index | 1.6 |
| Astrometry | |
| Radial velocity (Rv) | +32.865±0.001[5] km/s |
| Proper motion (μ) | RA: 294.923[1] mas/yr Dec.: 140.972[1] mas/yr |
| Parallax (π) | 42.7591 ± 0.0335[1] mas |
| Distance | 76.28 ± 0.06 ly (23.39 ± 0.02 pc) |
| Absolute magnitude (MV) | 8.50±0.09[4] |
| Details | |
| Mass | 0.64 M☉[6] 0.65±0.07[4] M☉ |
| Radius | 0.63 R☉[6] 0.61±0.04[4] R☉ |
| Luminosity | 0.095±0.018[4] L☉ |
| Surface gravity (log g) | 4.65±0.09[7] cgs |
| Temperature | 3,901±175 K[7]4,092±93[4] K |
| Metallicity [Fe/H] | +0.10±0.06 dex[6] −0.14 dex[7]0.01±0.17[8] dex |
| Rotational velocity (v sin i) | 1.5[6] km/s |
| Other designations | |
| Database references | |
| SIMBAD | data |
| Exoplanet Archive | data |
| Extrasolar Planets Encyclopaedia | data |
HIP 12961 is a star with an exoplanetary companion in the equatorial constellation of Eridanus. It is too faint to be visible to the naked eye, with an apparent visual magnitude of 10.24.[2] The distance to this system can be estimated from its parallax measurements, which yield a separation of 76.3 light-years from the Sun. It is receding with a radial velocity of +33 km/s[5] and has a high proper motion, traversing the celestial sphere at an angular rate of 0.300″ yr−1.[2]
This was classified as a cool red dwarf star of stellar classification M0 in 1980,[4] while C. B. Stephenson graded it as class K5V in 1986.[3] The absolute magnitude and color index of this star is a closer match to the former. It shows a high chromospheric activity level[4] and is one of the largest and brightest M class red dwarf stars known, with 64% of the mass and 63% of the radius of the Sun.[6] The star is radiating 10% of the luminosity of the Sun from its photosphere at an effective temperature of 4,092 K.[4]
HIP 12961 is named Koeia. The name was selected in the NameExoWorlds campaign by Puerto Rico, during the 100th anniversary of the IAU. Koeia was the word for star in the language of the Taíno Indigenous People of the Caribbean.[10][11]
Planetary system
HIP 12961 b is an extrasolar planet that was announced in a press release in October 2009.. This planet has at least half the mass of Jupiter and takes over eight weeks to orbit the host star at a separation of 0.25 AU and an eccentricity (ovalness) of 0.17.[12] The planet is named Aumatex. Aumatex was the god of wind in the mythology of the Taíno Indigenous People of the Caribbean.[10] The names were chosen by the Society of Women in Space Exploration- UPR-Humacao Chapter.[13]
| Companion (in order from star) |
Mass | Semimajor axis (AU) |
Orbital period (days) |
Eccentricity | Inclination | Radius |
|---|---|---|---|---|---|---|
| b / Aumatex | ≥0.35 MJ | 0.25 | 57.435 ± 0.042 | 0.166 ± 0.034 | — | — |
References
- ↑ 1.0 1.1 1.2 1.3 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.
- ↑ 2.0 2.1 2.2 2.3 2.4 2.5 2.6 Winters, Jennifer G. et al. (2015). "The Solar Neighborhood. XXXV. Distances to 1404 M Dwarf Systems within 25 Pc in the Southern Sky". The Astronomical Journal 149 (1): 5. doi:10.1088/0004-6256/149/1/5. Bibcode: 2015AJ....149....5W.
- ↑ 3.0 3.1 Stephenson, C. B. (July 1986). "Dwarf K and M stars of high proper motion found in a hemispheric survey". The Astronomical Journal 92: 139–165. doi:10.1086/114146. Bibcode: 1986AJ.....92..139S.
- ↑ 4.0 4.1 4.2 4.3 4.4 4.5 4.6 4.7 4.8 Gaidos, E. et al. (September 2014). "Trumpeting M dwarfs with CONCH-SHELL: a catalogue of nearby cool host-stars for habitable exoplanets and life". Monthly Notices of the Royal Astronomical Society 443 (3): 2561–2578. doi:10.1093/mnras/stu1313. Bibcode: 2014MNRAS.443.2561G.
- ↑ 5.0 5.1 Soubiran, C. et al. (2018). "Gaia Data Release 2. The catalogue of radial velocity standard stars". Astronomy and Astrophysics 616: A7. doi:10.1051/0004-6361/201832795. Bibcode: 2018A&A...616A...7S.
- ↑ 6.0 6.1 6.2 6.3 6.4 Lindgren, Sara; Heiter, Ulrike (2017). "Metallicity determination of M dwarfs. Expanded parameter range in metallicity and effective temperature". Astronomy and Astrophysics 604: A97. doi:10.1051/0004-6361/201730715. Bibcode: 2017A&A...604A..97L. https://www.aanda.org/articles/aa/full_html/2017/08/aa30715-17/aa30715-17.html.
- ↑ 7.0 7.1 7.2 Stassun, Keivan G. et al. (2016). "Accurate Empirical Radii and Masses of Planets and Their Host Stars with Gaia Parallaxes". The Astronomical Journal 153 (3): 136. doi:10.3847/1538-3881/aa5df3. Bibcode: 2017AJ....153..136S.
- ↑ Rojas-Ayala, Bárbara et al. (April 2012). "Metallicity and Temperature Indicators in M Dwarf K-band Spectra: Testing New and Updated Calibrations with Observations of 133 Solar Neighborhood M Dwarfs". The Astrophysical Journal 748 (2): 93. doi:10.1088/0004-637X/748/2/93. Bibcode: 2012ApJ...748...93R.
- ↑ "CD-23 1056". SIMBAD. Centre de données astronomiques de Strasbourg. http://simbad.u-strasbg.fr/simbad/sim-basic?Ident=CD-23+1056.
- ↑ 10.0 10.1 "Approved names" (in en). http://www.nameexoworlds.iau.org/final-results.
- ↑ "International Astronomical Union | IAU". https://www.iau.org/news/pressreleases/detail/iau1912/.
- ↑ 12.0 12.1 Forveille, Thierry et al. (February 2011). "The HARPS search for southern extra-solar planets: XXVIII. Two giant planets around M0 dwarfs". Astronomy & Astrophysics 526: A141. doi:10.1051/0004-6361/201016034. ISSN 0004-6361. Bibcode: 2011A&A...526A.141F.
- ↑ "Proposers". International Astronomical Union. https://www.nameexoworlds.iau.org/proposers.
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