This week, scientists at Georgia State University’s Center for High Angular Resolution Astronomy (CHARA) Array have made a significant breakthrough in the study of cannibalized stars. Utilizing powerful telescopes, the research team led by Postdoctoral Research Associate Robert Klement has completed a survey of a group of stars suspected to have devoured most of the gas from orbiting companion stars. The sensitive measurements have directly detected the feeble glow of the cannibalized stars.
The findings of this new research, published in The Astrophysical Journal, provide insights into the orbits of stripped subdwarf stars that circle fast-spinning massive stars, shedding light on the life trajectory of close binary stars.
Working in collaboration with colleagues at the CHARA Array in Mount Wilson, Calif., Klement directed the high-powered telescopes towards a collection of relatively nearby B-emission line stars, also known as ‘Be stars.’ These rapidly rotating stars are believed to harbor unusual orbiting companions.
It is suggested that Be stars are formed in intense interactions between close pairs of stars, a phenomenon particularly common among stars more massive than our sun. Pairs with small separations face a tumultuous destiny as they grow in size and can reach a dimension similar to their separation. When this occurs, gas from the growing star can cross the gap between the pair, allowing the companion to feast upon the transferred gas stream. Over time, this cannibalization process strips the mass donor star of almost all its gas, leaving behind the tiny hot core of its former nuclear-burning center.
The CHARA Array measurements of the motion of the stripped star that orbits the Be star HR2142 every 81 days have provided valuable insights. The research team’s observations have revealed the circular orbit of the stripped companion, which appears elliptical due to its tilt with respect to the plane of the sky. This discovery has significant implications for understanding the dynamics of these star systems.
Astronomers had previously predicted that the mass transfer stream causes the cannibalized stars to emit a feeble glow, and the recent findings from the CHARA Array have now directly detected this faint emission. This breakthrough in understanding the behavior of cannibalized stars opens new avenues for further exploration and research in the field of astronomy.
