DG Canum Venaticorum

DG Canum Venaticorum is a variable binary star system[3] in the northern constellation of Canes Venatici. As of 2009, the pair have an angular separation of 0.20″ along a position angle of 285°, which corresponds to a physical separation of around 3.6 AU.[8] With an apparent visual magnitude of 12.02, the pair are much too faint to be seen with the naked eye.[3] Parallax measurements place the system at a distance of roughly 59 light years from the Earth.[3]

DG Canum Venaticorum

A light curve for DG Canum Venaticorum, plotted from TESS data.[1] The main plot shows both the low amplitude periodic oscillations, and several flares. The inset plot shows the strongest flare with an expanded time scale.
Observation data
Epoch J2000.0      Equinox J2000.0
Constellation Canes Venatici
Right ascension 13h 31m 46.617s[2]
Declination +29° 16′ 36.72″[2]
Apparent magnitude (V) 12.02[3] (12.64 + 12.93)
Characteristics
Spectral type M4.0Ve[3]
Variable type Flare star + BY Dra[4]
Astrometry
Radial velocity (Rv)−7.50±6.50[3] km/s
Proper motion (μ) RA: −244.1±4.2[3] mas/yr
Dec.: −132.4±4.8[3] mas/yr
Parallax (π)55.51 ± 2.38 mas[3]
Distance59 ± 3 ly
(18.0 ± 0.8 pc)
Absolute magnitude (MV)10.74[3] (11.36 + 11.65)
Details
A
Mass0.39[5] M☉
Radius0.253[6] R☉
Temperature3,263[6] K
Metallicity [Fe/H]0.15[7] dex
Rotational velocity (v sin i)50[8] km/s
B
Mass+0.07[6] M☉
Age30[8] Myr
Other designations
DG CVn, G 165-8AB, GJ 3789, TYC 2003-139-1[9]
Database references
SIMBADdata
ARICNSdata

The stellar classification of the primary component is M4.0Ve, indicating it is a red dwarf with emission lines present. It is considered a very young system with an estimated age of just 30[8] million years and a higher metallicity than the Sun.[7] One of the components is rotating rapidly, with a projected rotational velocity of 50 km/s.[3] At least one of the members of this system is a type of variable known as a flare star, which means it undergoes brief increases in brightness at random intervals. On April 23, 2014, a gamma-ray superflare event was observed by the Swift satellite coming from the position of this system. It may have been perhaps the most luminous such events ever observed coming from a red dwarf star. A secondary radio flare was observed a day later.[8]

References
  1. "MAST: Barbara A. Mikulski Archive for Space Telescopes". Space Telescope Science Institute. Retrieved 8 December 2021.
  2. Høg, E.; et al. (March 2000), "The Tycho-2 catalogue of the 2.5 million brightest stars", Astronomy and Astrophysics, 355: L27–L30, Bibcode:2000A&A...355L..27H, doi:10.1888/0333750888/2862, ISBN 0333750888.
  3. Riedel, Adric R.; et al. (2014), "The Solar Neighborhood. XXXIII. Parallax Results from the CTIOPI 0.9 m Program: Trigonometric Parallaxes of Nearby Low-mass Active and Young Systems", The Astronomical Journal, 147 (4): 85, arXiv:1401.0722, Bibcode:2014AJ....147...85R, doi:10.1088/0004-6256/147/4/85, S2CID 14115792.
  4. 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.
  5. Cortés-Contreras, M.; Béjar, V. J. S.; Caballero, J. A.; Gauza, B.; Montes, D.; Alonso-Floriano, F. J.; Jeffers, S. V.; Morales, J. C.; Reiners, Ansgar; Ribas, I.; Schöfer, P.; Quirrenbach, A.; Amado, P. J.; Mundt, R.; Seifert, W. (2017). "CARMENES input catalogue of M dwarfs. II. High-resolution imaging with Fast Cam". Astronomy & Astrophysics. 597: A47. arXiv:1608.08145. Bibcode:2017A&A...597A..47C. doi:10.1051/0004-6361/201629056. S2CID 56332644.
  6. Houdebine, E. R; Mullan, D. J; Paletou, F; Gebran, M (2016). "Rotation-Activity Correlations in K and M Dwarfs. I. Stellar Parameters and Compilations of v sin i and P/sin i for a Large Sample of Late-K and M Dwarfs". The Astrophysical Journal. 822 (2): 97. arXiv:1604.07920. Bibcode:2016ApJ...822...97H. doi:10.3847/0004-637X/822/2/97. S2CID 119118088.
  7. Newton, Elisabeth R.; et al. (January 2014), "Near-infrared Metallicities, Radial Velocities, and Spectral Types for 447 Nearby M Dwarfs", The Astronomical Journal, 147 (1): 24, arXiv:1310.1087, Bibcode:2014AJ....147...20N, doi:10.1088/0004-6256/147/1/20, S2CID 26818462, 20.
  8. Fender, R. P.; et al. (January 2015), "A prompt radio transient associated with a gamma-ray superflare from the young M dwarf binary DG CVn", Monthly Notices of the Royal Astronomical Society: Letters, 446 (1): L66–L70, arXiv:1410.1545, Bibcode:2015MNRAS.446L..66F, doi:10.1093/mnrasl/slu165, S2CID 118483778.
  9. "DG CVn -- Flare Star", SIMBAD Astronomical Database, Centre de Données astronomiques de Strasbourg, retrieved 2016-03-11.
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