HIP 12961

HIP 12961 is a dim red dwarf star located approximately 75 light-years away[1] in the constellation of Eridanus. It is one of the largest and brightest M class red dwarf stars known. In 2009 an extrasolar planet orbiting this faint star has been announced.

HIP 12961
Observation data
Epoch J2000.0      Equinox J2000.0
Constellation Eridanus
Right ascension 02h 46m 42.89s[1]
Declination −23° 05′ 11.8″[1]
Apparent magnitude (V) 9.7
Characteristics
Spectral type M0V
Apparent magnitude (B) 11.3
Apparent magnitude (J) 7.558
Apparent magnitude (H) 6.927
Apparent magnitude (K) 6.736
B−V color index 1.6
Astrometry
Proper motion (μ) RA: 292.62 ± 1.60[1] mas/yr
Dec.: 140.88 ± 1.40[1] mas/yr
Parallax (π)43.45 ± 1.72[1] mas
Distance75 ± 3 ly
(23.0 ± 0.9 pc)
Absolute magnitude (MV)7.8
Details
Mass0.63 M☉
Radius0.68 ± 0.03 R☉
Luminosity0.101 ± 0.01 L☉
Surface gravity (log g)4.34 cgs
Temperature3,838 ± 19[2] K
Metallicity [Fe/H]+0.10±0.06[3] dex
Other designations
Koeia, TYC 6434-00494-1, CD-23 1056, LTT 1349, 2MASS J02464286-2305119, NLTT 8966, PPM 245393, SAO 168043
Database references
SIMBADdata
Exoplanet Archivedata
Extrasolar Planets
Encyclopaedia		data

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.[4][5]

Planetary system

HIP 12961 b is an extrasolar planet which orbits the star. This planet has at least half the mass of Jupiter and takes over eight weeks to orbit the star at a semimajor axis of approximately 0.25 AU. The planet's existence was announced in a press release in October 2009.

The planet HIP 12961 b is named Aumatex. Aumatex was the god of wind in the mythology of the Taíno Indigenous People of the Caribbean.[4]

The HIP 12961 planetary system[6]
Companion
(in order from star)		 Mass Semimajor axis
(AU)		 Orbital period
(days)		 Eccentricity Inclination Radius
b ≥0.35 MJ 0.25 57.435 ± 0.042 0.166 ± 0.034 — —

References
  1. 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. S2CID 18759600. Vizier catalog entry
  2. 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" (PDF). The Astrophysical Journal. 748 (2): 93. arXiv:1112.4567. Bibcode:2012ApJ...748...93R. doi:10.1088/0004-637X/748/2/93. S2CID 41902340.
  3. Lindgren, Sara; Heiter, Ulrike (2017). "Metallicity determination of M dwarfs. Expanded parameter range in metallicity and effective temperature". Astronomy and Astrophysics. 604: A97. arXiv:1705.08785. Bibcode:2017A&A...604A..97L. doi:10.1051/0004-6361/201730715. S2CID 119216828.
  4. "Approved names". NameExoworlds. Retrieved 2020-01-02.
  5. "International Astronomical Union | IAU". www.iau.org. Retrieved 2020-01-02.
  6. Forveille, T.; et al. (2011). "The HARPS search for southern extrasolar planets XXVI. Two giant planets around M0 dwarfs". Astronomy and Astrophysics. 526. A141. arXiv:1012.1168. Bibcode:2011A&A...526A.141F. doi:10.1051/0004-6361/201016034. S2CID 119230019.


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