Abstract

TAPIA, Mauricio et al. Periodic radio continuum emission associated with the β Cephei star V2187 CYG. Rev. mex. astron. astrofis [online]. 2014, vol.50, n.1, pp.127-136. ISSN 0185-1101.

We present new optical time-resolved photometry and medium-resolution spectroscopy of V2187 Cyg. We confirm its classification as a β Cephei star based on sinusoidal light variations with a period of 0.2539 days and mean amplitudes of 0.037 and 0.042 magnitudes in i and V, respectively. We classified the spectrum of this star as B2-3 V with no evidence of variations in the profiles of its absorption lines in timescales of hours or days. The stellar spectrum is totally absent of emission lines. We detected unexpected faint radio continuum emission (between 0.4 and 0.8 mJy at 6-cm) showing a sinusoidal variation with a period of 12.8 days. The radio spectrum is thermal. We searched in the Very Large Array archive for radio continuum emission toward 15 other β Cephei stars. None of these additional stars, some of them much closer to the Sun than V2187 Cyg, was detected, indicating that radio emission from β Cephei stars is extremely uncommon.

Keywords : radio continuum [stars]; stars [individual (V1287 Cyg, β Cephei)].

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