Gliese 105

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Gliese 105 A/B/C
Observation data
Epoch J2000      Equinox J2000
Constellation Cetus
Right ascension A: 02h 36m 04.89s[1] B: 02h 36m 15.0s
C: 02h 35m 58.8s
Declination A: +06° 53′ 12.7″[1]
B: +06° 52′ 18″
C: +06° 52′ 00″
Apparent magnitude (V) 5.82/11.66/16.9
Spectral type K3 V/M3.5 Vn/M7 V
U−B color index 0.81/1.12
B−V color index 0.97/1.60
Variable type None/BY Draconis
Radial velocity (Rv) 25.7 km/s
Proper motion (μ) RA: 1807.78 ± 0.89[1] mas/yr
Dec.: 1444.02 ± 0.40[1] mas/yr
Parallax (π) 139.27 ± 0.45[1] mas
Distance 23.42 ± 0.08 ly
(7.18 ± 0.02 pc)
Absolute magnitude (MV) 6.49/12.34/17.58
Mass 0.81/0.21/0.08 M
Radius 0.650 ± 0.053[2]/0.28 R
Luminosity 0.21/0.0001/0.0000075 L
Temperature 4,841[3] K
Metallicity 85.11%[3]/ ? Z
Rotation ?
Age 4.8-6.6 (Sun=4.6) ×109 years
Other designations
268 G. Ceti, BX Ceti (B only), Gl 105, HR 753, BD +06°398, HD 16160, LHS 15/16, LTT 10858/10859, GCTP 520.00, SAO 110636, FK5 1073, G 73-70/71, G 76-11/12, LFT 217/218, HIP 12114.
Database references
Gliese 105.

Gliese 105 (also known as 268 G. Ceti) is a triple star system in the constellation of Cetus. It is located relatively near the Sun at an estimated distance of less than 24 light years,[1] but even the brightest component is too faint to see directly with the unaided eye. No planets have yet been detected around any of the stars in this system.

The companion star B has a common proper motion with A, and the two have an estimated separation of 1,200 AUs. It is a BY Draconis variable star that has been given the designation "BX Ceti".

The third companion C lies much closer to A, at a distance of approximately 24 AU. The pair A-C have an estimated orbital period of 61 years. Component C is a relatively minuscule star that lies at the low end of the mass range needed to achieve nuclear fusion.


  1. ^ a b c d e f van Leeuwen, F. (2007). "Validation of the new Hipparcos reduction". Astronomy and Astrophysics. 474 (2): 653–664. arXiv:0708.1752free to read. Bibcode:2007A&A...474..653V. doi:10.1051/0004-6361:20078357.  Vizier catalog entry
  2. ^ van Belle, Gerard T.; von Braun, Kaspar (2009). "Directly Determined Linear Radii and Effective Temperatures of Exoplanet Host Stars". The Astrophysical Journal. 694 (2): 1085–1098. arXiv:0901.1206free to read. Bibcode:2009ApJ...694.1085V. doi:10.1088/0004-637X/694/2/1085. 
  3. ^ a b Soubiran, C.; Bienaymé, O.; Mishenina, T. V.; Kovtyukh, V. V. (2008). "Vertical distribution of Galactic disk stars. IV. AMR and AVR from clump giants". Astronomy and Astrophysics. 480 (1): 91–101. arXiv:0712.1370free to read. Bibcode:2008A&A...480...91S. doi:10.1051/0004-6361:20078788. 

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