Abstract
Abstract
Close binaries with active chromospheres have recently been shown to emit circularly polarized radio emission at low frequencies, motivating detailed studies of their orbital properties. We present high-resolution (
R
= 85,000) optical spectroscopy of TYC 2834-1385-1, a previously unclassified radio source, obtained with the HERMES spectrograph on the Mercator Telescope. We identify the source as a double-lined spectroscopic binary and measure radial velocities from both metallic absorption and Ca
ii
emission lines. We find an orbital period of
P
= 3.601 ± 0.002 days and nearly equal radial-velocity semi-amplitudes for the two components. The system exhibits strong Ca
ii
H and K emission, which is consistent with a BY Dra-type binary containing two similar late-G/early-K main-sequence stars, with a preliminary classification of K0V. This represents one of the first spectroscopic confirmations of a chromospherically active binary following its identification in a low-frequency radio survey.