Vampire Star

The Indian Institute of Astrophysics (IIA) recently discovered that a vampire star sucked material form a companion in the star cluster M67 located in the constellation Cancer.

Key findings of the Discovery:

• This discovery was made using data from the UltraViolet Imaging Telescope (UVIT) on board AstroSat, India’s first dedicated space observatory.
• The vampire star in M67, known as WOCS 9005, shows a chemical imprint of barium-rich material.
• The UVIT data, which revealed significant UV brightness originating from the hot and small companion star.
• The spectra revealed an atmosphere rich in heavy elements such as barium, yttrium, and lanthanum, which are typically produced in asymptotic giant branch (AGB) stars.
• It experimentally confirms the theoretical prediction that blue straggler stars acquire material from their companion stars, leading to their anomalous youth and luminosity.
• In a binary system, the more massive star evolves faster and enters the AGB phase, producing heavy elements through a process known as neutron capture (s-process).
• As the AGB star sheds its outer layers, these elements are transferred to the companion star. The companion, now enriched with heavy elements, appears rejuvenated and more luminous.

About Vampire Star:

• Vampire stars, known as blue straggler stars (BSS), defy simple models of stellar evolution and show many characteristics of younger stars.
• These stars appear younger and more luminous than other stars of similar age in their clusters, which has puzzled astronomers for decades.
• It is theorized to occur through a process where these stars “rejuvenate” by siphoning material from a companion star in a binary system, a process often referred to as mass transfer.
• Blue straggler stars are easily identified in star clusters.
• These clusters, born from the same molecular cloud, contain stars with similar surface chemistry, making them ideal for studying stellar evolution.

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