Gliese 412

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Gliese 412 A/B
Observation data
Epoch J2000      Equinox J2000
Constellation Ursa Major
Right ascension 11h 05m 28.5777s[1]
Declination +43° 31′ 36.394″[1]
Apparent magnitude (V) 8.68[2]/14.45[3]
Characteristics
Spectral type M2 V[2]/M6[3]
U−B color index +1.16/—[4]
B−V color index +1.54[4]/2.08[5]
Astrometry
Radial velocity (Rv) +64.9 ± 0.9[6] km/s
Proper motion (μ) RA: -4409.90[1] mas/yr
Dec.: 942.31[1] mas/yr
Parallax (π) 206.92 ± 1.19[1] mas
Distance 15.76 ± 0.09 ly
(4.83 ± 0.03 pc)
Absolute magnitude (MV) 10.34/16.05[7]
Details
Mass 0.48/0.10[7] M
Surface gravity (log g) 4.90[8]/— cgs
Temperature 3,687[8]/2,700[5] K
Metallicity -0.43[8]/—
Rotational velocity (v sin i) <3/7.7 ± 1.7[9] km/s
Other designations
GJ 412, BD+44°2051.[2]

A: G 176-11, LTT 12976, LFT 757, LHS 38, NLTT 26245, FK5 4979, SAO 43609, HIP 54211.[2]

B: WX UMa, G 176-12, LTT 12977, LFT 758, LHS 39, NLTT 26247.[3]

Gliese 412 is a pair of stars that share a common proper motion through space and are thought to form a binary star system. The pair have an angular separation of 31.4″ at a position angle of 126.1°.[10] They are located 15.8 light years distant from the Sun in the constellation Ursa Major. Both components are relatively dim red dwarf stars.

The two stellar components of this system are currently separated by about 190 AU.[11] The primary has about 48% of the Sun's mass, while the secondary is only 10%.[7] The primary has a projected rotation velocity at the equator of less than 3 km/s. The secondary has a rotation velocity of 7.7 ± 1.7 km/s.[9]

The primary star was monitored for radial velocity (RV) variations caused by a Jupiter-mass companion in a short period orbit. It displayed no significant excess of RV variation that could be attributed to a planet.[12] A search of the system using near-infrared speckle interferometry also failed to detect a companion orbiting at distances of 1–10 AU.[13] Nor was a brown dwarf been detected orbiting within this system.[14]

The space velocity components of this system are U = 141, V = –7 and W = 7. They are members of the halo population of the Milky Way galaxy.[9]

X-ray source[edit]

The secondary is a flare star that is referred to as WX Ursae Majoris. It is characterized as a UV Ceti type variable star that displays infrequent increases in luminosity. This star was observed to flare as early as 1939 by the Dutch astronomer Adriaan van Maanen.[15]

Component B (WX Ursae Majoris) has been identified as an X-ray source, while no significant X-ray emission was detected from component A.[16] This system had not been studied in X-rays prior to ROSAT.[16]

References[edit]

  1. ^ a b c d e Perryman, M. A. C. et al. (1997), The Hipparcos Catalogue, Astronomy & Astrophysics 323: L49–L52, Bibcode:1997A&A...323L..49P 
  2. ^ a b c d "LHS 38 – High proper-motion Star". Centre de Données astronomiques de Strasbourg. Retrieved 2008-05-16. 
  3. ^ a b c "V* WX UMa -- Flare Star". Centre de Données astronomiques de Strasbourg. Retrieved 2008-05-16. 
  4. ^ a b Nicolet, B. (1978). "Photoelectric photometric Catalogue of homogeneous measurements in the UBV System". Observatory. Bibcode:1978ppch.book.....N. 
  5. ^ a b Casagrande, Luca; et al. (September 2008). "M dwarfs: effective temperatures, radii and metallicities". Monthly Notices of the Royal Astronomical Society 389 (2): 585–607. arXiv:0806.2471. Bibcode:2008MNRAS.389..585C. doi:10.1111/j.1365-2966.2008.13573.x. 
  6. ^ Evans, D. S. (June 20–24, 1966). "The Revision of the General Catalogue of Radial Velocities". In Batten, Alan Henry; Heard, John Frederick. "Determination of Radial Velocities and their Applications, Proceedings from IAU Symposium no. 30". University of Toronto: International Astronomical Union. Retrieved 2009-09-10. 
  7. ^ a b c "The 100 nearest star systems". Research Consortium on Nearby Stars. 2009-09-14. Retrieved 2009-09-14. 
  8. ^ a b c Soubiran, C.; Bienaymé, O.; Mishenina, T. V.; Kovtyukh, V. V. (March 2008). "Vertical distribution of Galactic disk stars. IV. AMR and AVR from clump giants". Astronomy and Astrophysics 480 (1): 91–101. arXiv:0712.1370. Bibcode:2008A&A...480...91S. doi:10.1051/0004-6361:20078788. 
  9. ^ a b c Delfosse, X.; et al. (March 1998). "Rotation and chromospheric activity in field M dwarfs". Astronomy and Astrophysics 331: 581–595. Bibcode:1998A&A...331..581D. 
  10. ^ Gould, Andrew; Chanamé, Julio (February 2004). "New Hipparcos-based Parallaxes for 424 Faint Stars". The Astrophysical Journal Supplement Series 150 (2): 455–464. arXiv:astro-ph/0309001. Bibcode:2004ApJS..150..455G. doi:10.1086/381147. 
  11. ^ Reid, I. Neill; Gizis, John E. (June 1997). "Low-Mass Binaries and the Stellar Luminosity Function". Astronomical Journal 113: 2246–2269. Bibcode:1997AJ....113.2246R. doi:10.1086/118436. 
  12. ^ Endl, Michael; et al. (September 2006). "Exploring the Frequency of Close-in Jovian Planets around M Dwarfs". The Astrophysical Journal 649 (1): 436–443. arXiv:astro-ph/0606121. Bibcode:2006ApJ...649..436E. doi:10.1086/506465. 
  13. ^ Leinert, C.; et al. (September 1997). "A search for companions to nearby southern M dwarfs with near-infrared speckle interferometry". Astronomy and Astrophysics 325: 159–166. Bibcode:1997A&A...325..159L. 
  14. ^ Oppenheimer, B. R.; et al. (April 2001). "A Coronagraphic Survey for Companions of Stars within 8 Parsecs". The Astronomical Journal 121 (4): 2189–2211. arXiv:astro-ph/0101320. Bibcode:2001AJ....121.2189O. doi:10.1086/319941. 
  15. ^ Joy, Alfred H. (June 1967). "Stellar Flares". Astronomical Society of the Pacific Leaflets 10 (456): 41–48. Bibcode:1967ASPL...10...41J. 
  16. ^ a b Schmitt JHMM, Fleming TA, Giampapa MS (September 1995). "The X-Ray View of the Low-Mass Stars in the Solar Neighborhood". Ap J. 450 (9): 392–400. Bibcode:1995ApJ...450..392S. doi:10.1086/176149. 

See also[edit]