Astronomy:GJ 3685

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Short description: Star in the constellation Leo
GJ 3685
Observation data
Equinox J2000.0]] (ICRS)
Constellation Leo
Right ascension  11h 47m 40.74723s[1]
Declination +00° 15′ 20.1018″[1]
Apparent magnitude (V) 13.34[2]
Characteristics
Spectral type M4V[3]
V−R color index +1.22[4]
R−I color index +1.55[4]
Variable type Flare star
Astrometry
Radial velocity (Rv)7.02 ± 0.32[5] km/s
Proper motion (μ) RA: −314.284[1] mas/yr
Dec.: −100.757[1] mas/yr
Parallax (π)53.1361 ± 0.0304[1] mas
Distance61.38 ± 0.04 ly
(18.82 ± 0.01 pc)
Details
Surface gravity (log g)4.5[6] cgs
Temperature3100[6] K
Metallicity0.23[3]
Rotational velocity (v sin i)5.60 ± 1.40[5] km/s
Other designations
LP 613-49, LTT 13239, G 10-49, G 11-21[7]
Database references
SIMBADdata
ARICNSdata

GJ 3685 is a star in the constellation of Leo. It is extremely faint; its apparent magnitude is 13.3,[2] and can only be seen with a ten-inch (25 cm) telescope (see Limiting magnitude). Based on a parallax of 53.1361 milliarcseconds,[1] the system is located 61.4 light-years (18.8 parsecs) away from the Earth.

This is a part of a binary star system consisting of two components separated by 24″.[8] The primary component, GJ 3685 (also known as GJ 3685 A), is a very old red dwarf that is also a flare star. A 20-minute flare was observed in 2004 by the GALEX satellite.[9] Its companion, GJ 3686, is another faint red dwarf with a spectral type of M5. It is also known as LP 613-50 and is also located roughly the same distance as its primary.[10]

References

  1. 1.0 1.1 1.2 1.3 1.4 Vallenari, A. et al. (2022). "Gaia Data Release 3. Summary of the content and survey properties". Astronomy & Astrophysics. doi:10.1051/0004-6361/202243940  Gaia DR3 record for this source at VizieR.
  2. 2.0 2.1 Zacharias, N. (2012). "The fourth US Naval Observatory CCD Astrograph Catalog (UCAC4)". VizieR On-line Data Catalog 1322. Bibcode2012yCat.1322....0Z. 
  3. 3.0 3.1 Newton, Elisabeth R. (2014). "Near-infrared Metallicities, Radial Velocities, and Spectral Types for 447 Nearby M Dwarfs". The Astronomical Journal 147 (1): 20. doi:10.1088/0004-6256/147/1/20. Bibcode2014AJ....147...20N. 
  4. 4.0 4.1 "N1 990 A". ARICNS. Centre of Astronomy, Heidelberg University. 5 November 1998. https://wwwadd.zah.uni-heidelberg.de/datenbanken/aricns/cnspages/4c04017.htm. 
  5. 5.0 5.1 Deshpande, R.; Blake, C. H.; Bender, C. F.; Mahadevan, S.; Terrien, R. C.; Carlberg, J. K.; Zasowski, G.; Crepp, J. et al. (2013). "The Sdss-Iii Apogee Radial Velocity Survey of M Dwarfs. I. Description of the Survey and Science Goals". The Astronomical Journal 146 (6): 156. doi:10.1088/0004-6256/146/6/156. Bibcode2013AJ....146..156D. 
  6. 6.0 6.1 Lépine, Sébastien (2013). "A Spectroscopic Catalog of the Brightest (J < 9) M Dwarfs in the Northern Sky". The Astronomical Journal 145 (4): 102. doi:10.1088/0004-6256/145/4/102. Bibcode2013AJ....145..102L. 
  7. "GJ 3685 A -- Flare Star". SIMBAD Astronomical Database. Centre de données astronomiques de Strasbourg. http://simbad.u-strasbg.fr/simbad/sim-id?protocol=html&Ident=GJ+3685&NbIdent=1&Radius=2&Radius.unit=arcmin&submit=submit+id. 
  8. "N1 990 B". ARICNS. Centre of Astronomy, Heidelberg University. 5 November 1998. https://wwwadd.zah.uni-heidelberg.de/datenbanken/aricns/cnspages/4c04018.htm. 
  9. Robinson, Richard D.; Wheatley, Jonathan M.; Welsh, Barry Y.; Forster, Karl; Morrissey, Patrick; Seibert, Mark; Rich, R. Michael; Salim, Samir et al. (2005). "GALEX Observations of an Energetic Ultraviolet Flare on the dM4e Star GJ 3685A". The Astrophysical Journal 633 (1): 447–51. doi:10.1086/444608. Bibcode2005ApJ...633..447R. 
  10. Phan-Bao, N.; Bessell, M. S. (2006). "Spectroscopic distances of nearby ultracool dwarfs". Astronomy and Astrophysics 446 (2): 515–523. doi:10.1051/0004-6361:20054064. Bibcode2006A&A...446..515P.