MACHO 311.37557.169: A VY Scl star

Optical surveys, such as the MACHO project, often uncover variable stars whose classification requires follow‑up observations by other instruments. We performed X‑ray spectroscopy and photometry of the unusual variable star MACHO 311.37557.169 with XMM‑Newton in April 2018, supplemented by archival X‑ray and optical spectrographic data. The star has a bolometric X‑ray luminosity of about 1 × 1032 erg s−1 cm−2 and a heavily absorbed two‑temperature plasma spectrum. The shape of its light curve, its overall brightness, its X‑ray spectrum, and the emission lines in its optical spectrum suggest that it is most likely a VY Scl cataclysmic variable.