Researchers from the Indian Institute of Astrophysics (IIA) have made the discovery that a vampire star has been rejuvenating its youth by sucking up material from a companion in the star cluster M67 located in the constellation Cancer.
The study provides rare insights into the binary star evolution process and provides an important missing link in the rejuvenation in these stars.
Vampire stars, known to astronomers as blue straggler stars (BSS), are identified easily in star clusters. These stars defy simple models of stellar evolution and show many characteristics of younger stars.
This anomalous youth is explained theoretically as due to rejuvenation by eating up material from a binary stellar companion known as mass transfer in a binary system.
Star clusters are useful test-beds to test this theory as they host a large number of binary stars, some of which can lead to the formation of vampire stars.
Once rejuvenated, these stars follow a different path of evolution when compared to Sun-like single stars. So far, detection of sucked up material along with the sighting of their remnant binary companion was elusive.
Star clusters, being born from the same molecular cloud, can contain hundreds to thousands of stars with a wide range of masses but all contain very similar surface chemistry, making them ideal laboratories to understand how single and binary stars live and die.
One such intriguing star cluster is M67, a collection of over 500 stars that are loosely gravitationally bound, a grouping known as an open cluster.
The scientists studied the surface composition of the vampire star in M67, called WOCS 9005, using spectroscopy, a technique where the light of the star is dispersed into its colors like the rainbow.
