Wolf 424 is a binary star system comprising two red dwarf stars. The stars are located at a distance of 14.37 light-years and hence are among the nearest stars, but due to their faint intrinsic brightness, they are not visible to the naked eye. Wolf 424 is located in the constellation Virgo, between the stars ε Virginis and ο Virginis.
An ultraviolet bandlight curve for FL Virginis, adapted from Moffett (1972).[14] The plot shows intensity above the star's quiescent intensity.
The close binary nature of this star was discovered by Dutch American astronomer Dirk Reuyl in 1941, based upon an elongation of the star found in photographs.[3] The two stars in the Wolf 424 system orbit about each other with a semi-major axis of 4.1 AU and an eccentricity of 0.3. The stars have an orbital period of 15.5 years and have a combined apparent magnitude of about 12.5.
Wolf 424A and Wolf 424B are similar-spectrum and similar-size stars, both red dwarfs with masses of 0.138 and 0.126 M☉ and radii of 0.150 and 0.153 R☉, respectively.[11] In 1967, it was discovered that both are flare stars that undergo random increases in luminosity. The system has been designated FL Virginis, and may experience sunspot activity. The stars may undergo variation in the level of flare activity over periods lasting several years.[4]
^ abCutri, Roc M.; Skrutskie, Michael F.; Van Dyk, Schuyler D.; Beichman, Charles A.; Carpenter, John M.; Chester, Thomas; Cambresy, Laurent; Evans, Tracey E.; Fowler, John W.; Gizis, John E.; Howard, Elizabeth V.; Huchra, John P.; Jarrett, Thomas H.; Kopan, Eugene L.; Kirkpatrick, J. Davy; Light, Robert M.; Marsh, Kenneth A.; McCallon, Howard L.; Schneider, Stephen E.; Stiening, Rae; Sykes, Matthew J.; Weinberg, Martin D.; Wheaton, William A.; Wheelock, Sherry L.; Zacarias, N. (2003). "VizieR Online Data Catalog: 2MASS All-Sky Catalog of Point Sources (Cutri+ 2003)". CDS/ADC Collection of Electronic Catalogues. 2246: II/246. Bibcode:2003yCat.2246....0C. S2CID115529446.
^Wilson, Ralph Elmer (1953). "General Catalogue of Stellar Radial Velocities". Carnegie Institute Washington D.C. Publication. Washington: Carnegie Institution of Washington. Bibcode:1953GCRV..C......0W.
^ abcCifuentes, C.; Caballero, J. A.; González-Payo, J.; Amado, P. J.; Béjar, V. J. S.; Burgasser, A. J.; Cortés-Contreras, M.; Lodieu, N.; Montes, D.; Quirrenbach, A.; Reiners, A.; Ribas, I.; Sanz-Forcada, J.; Seifert, W.; Zapatero Osorio, M. R. (January 2025). "CARMENES input catalogue of M dwarfs. IX. Multiplicity from close spectroscopic binaries to ultra-wide systems". Astronomy and Astrophysics. 693: A228. Bibcode:2025A&A...693A.228C. doi:10.1051/0004-6361/202452527. ISSN0004-6361.