Astronomers report the discovery of a new binary system, designated LAMOST J065816.72+094343.1. The newfound binary consists of a massive and hot subdwarf and an unseen companion. The finding was detailed in the January issue of the Astronomy & Astrophysics journal.

LAMOST J065816.72+094343.1, or J0658 for short, was first identified in 2018 by the Large Sky Area Multi-Object Fiber Spectroscopic Telescope (LAMOST) and classified as a hot subdwarf star of an sdOB type. Initial observations of J0658 have found that it is a helium-poor star with an effective temperature of about 35,800 K and a projected rotational velocity of 37 km/s.

Given that very little is known about J0658, a team of astronomers led by Fabian Mattig of the University of Potsdam in Germany decided to analyze the archival LAMOST data and to conduct follow-up observations of this star with the Southern Astrophysical Research (SOAR) telescope and the Very Large Telescope (VLT), hoping to unveil its true nature.