Detection of 6‐cm radio‐continuum emission from an EB (β‐Lyrae type) variable star – HIP 68718

• Published in: Monthly notices of the Royal Astronomical Society Vol. 381; no. 3; pp. 1027 - 1030
• Main Authors: Anderson, M. W. B., Filipović, M. D.
• Format: Journal Article
• Language: English
• Published: Oxford, UK Blackwell Publishing Ltd 01.11.2007; Blackwell Science; Oxford University Press
• Subjects: Astronomy; Astrophysics; binaries: eclipsing; Earth, ocean, space; Exact sciences and technology; Radio astronomy; radio continuum: stars; Spectrum analysis; Stars & galaxies; stars: individual: MR Vir; stars: individual: MR Vir; binaries: eclipsing; radio continuum: stars; Eclipsing binary stars; Continuum; Radio emission; Light curves; Luminosity; Spectral type; Radio stars; Radioastronomical position; Sky surveys
• ISSN: 0035-8711; 1365-2966
• DOI: 10.1111/j.1365-2966.2007.11783.x

We report the 6‐cm radio‐continuum detection of a previously unknown radio star, HIP 68718, identified by the Hipparcos satellite as an EB or β‐Lyrae type optical variable. Only five prior radio detections of this type are reported in the literature. The radio source (VLA J140402−002145) was detected at the 6σ level, with an associated <1 arcsec position error. The radio‐optical separation is 0.2 arcsec and is well within the position errors. A ROSAT X‐ray source (RXJ 1404.0−0021) is located 4.5 arcsec from the radio position. Based on the component spectral types (F5V + G5V), 1.52 d period, variations in the peak of the light curve and the X‐ray and 6‐cm radio luminosities, we conclude the star is a candidate RS CVn. The binary is in a near‐contact phase based on the asymmetric light curve (O'Connell effect). Evidence of two faint possible companion objects was also found in the J‐ and K‐band Two‐Micron All‐Sky Survey images.