Astrosat and Vampire star - GEOGRAPHY
News:
Researchers have made a groundbreaking discovery of a
vampire star in the star cluster M67 located in the constellation
Cancer, that has been rejuvenating its youth by sucking up material from a
companion.
What’s
in the news?
- The study provides rare insights into
the binary star evolution process and provides an
important missing link in the rejuvenation in these stars.
Details:
- Recently, a team of astronomers from
the Indian Institute of Astrophysics (IIA), an autonomous
institute of the Department of Science & Technology, Government of
India made a groundbreaking discovery of a vampire star in M67,
that sheds light on a complex rejuvenation process, known as mass-transfer
in a binary system.
- Scientists studied the vampire star
WOCS 9005 in the M67 cluster using
spectroscopy, revealing its surface chemistry is rich in heavy elements
like barium, yttrium, and lanthanum.
- The team used data from the GALAH
survey and the HERMES spectrograph, finding the heavy elements typical
of asymptotic giant branch (AGB) stars, which are more evolved
and massive than WOCS 9005.
- The presence of these heavy elements
suggested WOCS 9005 was polluted by a companion star that
had gone through its AGB phase and become a white dwarf.
- This makes WOCS 9005 the first
barium blue straggler star discovered in the M67
cluster.
- The team confirmed a small white
dwarf companion using the Ultra-Violet Imaging Telescope (UVIT) on
AstroSat, detecting significant UV brightness from the companion.
- Theoretical calculations validated
that mass transfer from the AGB star through
the wind was responsible for the heavy element pollution and rejuvenation
of WOCS 9005.
What
is Mass transfer in a Binary system?
- Mass
transfer in a binary system occurs when material from one star, an
evolved star like an asymptotic giant branch (AGB) star, is
transferred to its companion star. This process can suggestively alter the
companion's composition and appearance, often rejuvenating it, as seen in
the case of blue straggler stars.
About
Vampire Star:
Vampire
stars, also known as blue straggler stars (BSS), are found
in star clusters and appear younger than their neighboring
stars, challenging simple stellar evolution models. These stars are naturally
in pairs, known as symbiotic binaries, where the smaller
star consumes material from its companion. Over time, the sucking star
becomes larger and turns into a blue straggler.
Source:
https://pib.gov.in/PressReleasePage.aspx?PRID=2040159