Gliese 3685

Gliese 3685 is a star in the constellation of Leo. It is extremely faint; its apparent magnitude is 13.3,[1] and can only be seen with a ten-inch (25 cm) telescope (see Limiting magnitude). Based on a parallax of 50.30 milliarcseconds,[5] the system is located 65 light years (20 parsecs) away from the Earth.

Gliese 3685

Observation data Epoch J2000      Equinox J2000
Constellation	Leo
Right ascension	11^h 47^m 40.748^s[1]
Declination	+00° 15′ 20.15″[1]
Apparent magnitude (V)	13.34[1]
Characteristics
Spectral type	M4V[2]
V−R color index	+1.22[3]
R−I color index	+1.55[3]
Variable type	Flare star
Astrometry
Radial velocity (Rv)	7.02 ± 0.32[4] km/s
Proper motion (μ)	RA: −313.2[1] mas/yr Dec.: −95.9[1] mas/yr
Parallax (π)	50.30 ± 2.80[5] mas
Distance	65 ± 4 ly (20 ± 1 pc)
Details
Surface gravity (log g)	4.5[6] cgs
Temperature	3100[6] K
Metallicity	0.23[2]
Rotational velocity (v sin i)	5.60 ± 1.40[4] km/s
Other designations
LP 613-49, LTT 13239, G 10-49, G 11-21
Database references
SIMBAD	data
ARICNS	data

This is a part of a binary star system consisting of two components separated by 24″.[7] The primary component, Gliese 3685 (also known as Gliese 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.[8] Its companion, Gliese 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.[9]

References

1. Zacharias, N. (2012). "The fourth US Naval Observatory CCD Astrograph Catalog (UCAC4)". VizieR On-line Data Catalog. 1322. Bibcode:2012yCat.1322....0Z.
2. Newton, Elisabeth R. (2014). "Near-infrared Metallicities, Radial Velocities, and Spectral Types for 447 Nearby M Dwarfs". The Astronomical Journal. 147 (1): 20. arXiv:1310.1087. Bibcode:2014AJ....147...20N. doi:10.1088/0004-6256/147/1/20. S2CID 26818462.
3. "N1 990 A". ARICNS. Centre of Astronomy, Heidelberg University. 5 November 1998. Retrieved 21 March 2017.
4. Deshpande, R.; Blake, C. H.; Bender, C. F.; Mahadevan, S.; Terrien, R. C.; Carlberg, J. K.; Zasowski, G.; Crepp, J.; Rajpurohit, A. S.; Reylé, C.; Nidever, D. L.; Schneider, D. P.; Prieto, C. Allende; Bizyaev, D.; Ebelke, G.; Fleming, S. W.; Frinchaboy, P. M.; Ge, J.; Hearty, F.; Hernández, J.; Malanushenko, E.; Malanushenko, V.; Majewski, S. R.; Marchwinski, R.; Muna, D.; Oravetz, D.; Pan, K.; Schiavon, R. P.; Shetrone, M.; 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. arXiv:1307.8121. Bibcode:2013AJ....146..156D. doi:10.1088/0004-6256/146/6/156. S2CID 118667962.
5. Dittmann, Jason A.; Irwin, Jonathan M.; Charbonneau, David; Berta-Thompson, Zachory K. (2014). "Trigonometric Parallaxes for 1507 Nearby Mid-To-Late M Dwarfs". The Astrophysical Journal. 784 (2): 156. arXiv:1312.3241. Bibcode:2014ApJ...784..156D. doi:10.1088/0004-637X/784/2/156. S2CID 18789867.
6. Lépine, Sébastien (2013). "A Spectroscopic Catalog of the Brightest (J < 9) M Dwarfs in the Northern Sky". The Astronomical Journal. 145 (4): 102. arXiv:1206.5991. Bibcode:2013AJ....145..102L. doi:10.1088/0004-6256/145/4/102. S2CID 117144290.
7. "N1 990 B". ARICNS. Centre of Astronomy, Heidelberg University. 5 November 1998. Retrieved 21 March 2017.
8. Robinson, Richard D.; Wheatley, Jonathan M.; Welsh, Barry Y.; Forster, Karl; Morrissey, Patrick; Seibert, Mark; Rich, R. Michael; Salim, Samir; Barlow, Tom A.; Bianchi, Luciana; Byun, Yong-Ik; Donas, Jose; Friedman, Peter G.; Heckman, Timothy M.; Jelinsky, Patrick N.; Lee, Young-Wook; Madore, Barry F.; Malina, Roger F.; Martin, D. Christopher; Milliard, Bruno; Neff, Susan G.; Schiminovich, David; Siegmund, Oswald H. W.; Small, Todd; Szalay, Alex S.; Wyder, Ted K. (2005). "GALEX Observations of an Energetic Ultraviolet Flare on the dM4e Star GJ 3685A". The Astrophysical Journal. 633 (1): 447–51. arXiv:astro-ph/0507396. Bibcode:2005ApJ...633..447R. doi:10.1086/444608. S2CID 14054351.
9. Phan-Bao, N.; Bessell, M. S. (2006). "Spectroscopic distances of nearby ultracool dwarfs". Astronomy and Astrophysics. 446 (2): 515–523. arXiv:astro-ph/0509321. Bibcode:2006A&A...446..515P. doi:10.1051/0004-6361:20054064. S2CID 18565840.

• "GJ 3685 A -- Flare Star". SIMBAD Astronomical Database. Centre de données astronomiques de Strasbourg.