Gliese 105

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Gliese 105
Observation data
Epoch J2000      Equinox J2000
Constellation Cetus
Gliese 105 A
Right ascension 02h 36m 04.89466s[1]
Declination +06° 53′ 12.7466″[1]
Apparent magnitude (V) 5.83[2]
Gliese 105 B
Right ascension 02h 36m 15.357s[3]
Declination +06° 52′ 19.14″[3]
Apparent magnitude (V) 11.670[4]
Gliese 105 C
Right ascension 02h 36m 04.66s[5]
Declination +06° 53′ 14.8″[5]
Apparent magnitude (V) 16.77[5]
Gliese 105 AC
Spectral type K3 V[2] + M7 V[6]
U−B color index +0.800[7]
B−V color index +0.972[7]
Gliese 105 B
Spectral type M4.0 V
U−B color index +1.10[8]
B−V color index +1.61[8]
Variable type BY Dra
Radial velocity (Rv)25.8 ± 0.1[9] 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
Distance23.42 ± 0.08 ly
(7.18 ± 0.02 pc)
Absolute magnitude (MV)6.50[10]
Gliese 105 A
Mass0.70 ± 0.10[11] M
Radius0.650 ± 0.053[2] R
Luminosity (bolometric)0.26[11] L
Surface gravity (log g)4.40 ± 0.24[12] cgs
Temperature4777 ± 91[12] K
Metallicity [Fe/H]−0.03 ± 0.09[12] dex
Gliese 105 B
Mass0.246 ± 0.025[4] M
Radius0.278 ± 0.010[4] R
Temperature3284 ± 60[4] K
Other designations
268 G. Cet, Gl 105, CCDM J02361+0653, BD+06° 398
Gliese 105 AC: HR 753, HD 16160, LHS 15, LTT 10858, SAO 110636, FK5 1073, G 73-70, G 76-11, LFT 217, HIP 12114
Gliese 105 B: BX Cet, LHS 16, LTT 10859, G 73-71, G 76-12, LFT 217
Database references
Gl 105 A
Gl 105 B
Gl 105 C
Gliese 105 A (left) and C (right)

Gliese 105 (also known as 268 G. Ceti) is a multiple star system in the constellation of Cetus. It is located relatively near the Sun at a distance of 23 light-years (7 parsecs).[1] Despite this, even the brightest component is barely visible with the unaided eye (see Bortle scale). No planets have yet been detected around any of the stars in this system.

This is a triple system with three stars that are all less massive than the Sun. The brightest component is designated HD 16160, and is known as Gliese 105 A. It is a K-type main-sequence star,[2] about 70% the mass of the Sun.[11]

A nearby star has a similar proper motion to Gliese 105 A, so it is assumed to be physically associated with the primary, and is known as Gliese 105 B. The two have an estimated separation of 1,200 astronomical units (au). It is a BY Draconis variable star whose brightness varies between 11.64 and 11.68 magnitudes; for that reason it has been given the designation BX Ceti.[13]

A third companion, known as Gliese 105 C, lies much closer to A, currently at a distance of approximately 24 au.[6] The pair A-C have an estimated orbital period of 61 years.[6] While detected directly, Gliese 105 C has also been observed to perturb Gliese 105 A from its usual position;[6] from that, its orbit is estimated to have a high eccentricity of around 0.75 and a semimajor axis of 15 au.[6] Gliese 105 C is an extremely faint red dwarf.[6] It is roughly 8 to 9 percent the mass of the Sun, and it is about 20,000 times fainter than its parent star in visible light—at a distance of 1 au (the distance from the Earth to the Sun) it would only be four times brighter than the full moon.[14]


  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:0708.1752Freely accessible. Bibcode:2007A&A...474..653V. doi:10.1051/0004-6361:20078357.  Vizier catalog entry
  2. ^ a b c d 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:0901.1206Freely accessible. Bibcode:2009ApJ...694.1085V. doi:10.1088/0004-637X/694/2/1085. 
  3. ^ a b Cutri, R. M. (2003). "2MASS All-Sky Catalog of Point Sources". VizieR On-line Data Catalog. 2246. Bibcode:2003yCat.2246....0C. 
  4. ^ a b c d Mann, Andrew W.; Feiden, Gregory A.; Gaidos, Eric; Boyajian, Tabetha; von Braun, Kaspar (2015). "How to Constrain Your M Dwarf: Measuring Effective Temperature, Bolometric Luminosity, Mass, and Radius". The Astrophysical Journal. 804 (1): 38. arXiv:1501.01635Freely accessible. Bibcode:2015ApJ...804...64M. doi:10.1088/0004-637X/804/1/64. 
  5. ^ a b c "GJ 105 C". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 4 June 2017. 
  6. ^ a b c d e f Golimowski, David A.; et al. (2000). "The Very Low Mass Component of the Gliese 105 System". The Astronomical Journal. 120 (4): 2082–2088. arXiv:astro-ph/0006230Freely accessible. Bibcode:2000AJ....120.2082G. doi:10.1086/301567. 
  7. ^ a b González-Hernández, J. I.; Bonifacio, P. (2009). "A new implementation of the infrared flux method using the 2MASS catalogue". Astronomy & Astrophysics. 497 (2): 497. arXiv:0901.3034Freely accessible. Bibcode:2009A&A...497..497G. doi:10.1051/0004-6361/200810904. 
  8. ^ a b Mermilliod, J.-C. (1986). "Compilation of Eggen's UBV data, transformed to UBV (unpublished)". Bibcode:1986EgUBV........0M. 
  9. ^ Gontcharov, G. A. (2006). "Pulkovo Compilation of Radial Velocities for 35 495 Hipparcos stars in a common system". Astronomy Letters. 32 (11): 759–771. arXiv:1606.08053Freely accessible. Bibcode:2006AstL...32..759G. doi:10.1134/S1063773706110065. 
  10. ^ Cardini, D. (January 2005), "Mg II chromospheric radiative loss rates in cool active and quiet stars", Astronomy and Astrophysics, 430: 303–311, arXiv:astro-ph/0409683Freely accessible, Bibcode:2005A&A...430..303C, doi:10.1051/0004-6361:20041440. 
  11. ^ a b c Ghezzi, L.; Cunha, K.; Smith, V. V.; De Araújo, F. X.; Schuler, S. C.; de la Reza, R. (2010). "Stellar Parameters and Metallicities of Stars Hosting Jovian and Neptunian Mass Planets: A Possible Dependence of Planetary Mass on Metallicity". The Astrophysical Journal. 720 (2): 1290. arXiv:1007.2681Freely accessible. Bibcode:2010ApJ...720.1290G. doi:10.1088/0004-637X/720/2/1290. 
  12. ^ a b c Paletou, F.; Böhm, T.; Watson, V.; Trouilhet, J.-F. (2014). "Inversion of stellar fundamental parameters from ESPaDOnS and Narval high-resolution spectra". Astronomy & Astrophysics. 573: A67. arXiv:1411.4859Freely accessible. Bibcode:2015A&A...573A..67P. doi:10.1051/0004-6361/201424741. 
  13. ^ Samus, N. N.; Durlevich, O. V.; et al. (2009). "VizieR Online Data Catalog: General Catalogue of Variable Stars (Samus+ 2007-2013)". VizieR On-line Data Catalog: B/gcvs. Originally published in: 2009yCat....102025S. 1. Bibcode:2009yCat....102025S. 
  14. ^ "A Really Cool Star: The Dim, Low-Temperature GL 105C". HubbleSite. 14 September 1995. Retrieved 4 June 2017. 

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