Star ripped apart by black hole in rare discovery
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Illustration
shows the remnants of a star shredded by a supermassive black hole. (Credit:
NASA’s Goddard Space Flight Center/Chris Smith (USRA/GESTAR))
Astronomers from the University of Hawaiʻi Institute for Astronomy (IfA)
have uncovered the closest recorded occurrence of a star being torn apart by a
supermassive black hole (SMBH). Using
the All-Sky Automated Survey for SuperNovae (ASAS-SN) system, on February 22,
2023,the team detected a sudden surge in brightness followed by a rapid dimming
in the galaxy NGC 3799, located about 160 million light-years from Earth.
“While black holes destroying stars have been
seen before, this is the first one we have seen this close using visible
light,” said Willem Hoogendam, an IfA graduate student who co-led the research.
“This could give us a much better understanding of how SMBHs grow and collect
material around them.”
Follow-up observations were taken with IfA’s Asteroid Terrestrial Last Alert System
(ATLAS) telescopes on Maunaloa and Haleakalā, W.M. Keck Observatory on Maunakea,
and other ground- and space-based observatories. Hoogendam, working with fellow
IfA grad student Jason Hinkle and faculty advisor Ben Shappee, analyzed these
data to determine that the burst of brightness was caused by a Tidal Disruption
Event (TDE). TDEs happen when a star gets too close to a SMBH and is torn apart
by its strong gravitational force, with the black hole devouring the star’s
mass. Research findings will be published in the Monthly Notices of the Royal
Astronomical Society.
“This discovery suggests that black holes
ripping stars apart nearby could be more common than previously thought—we just
haven’t witnessed it happening frequently,” said Hoogendam.
Rare find
The intense brightness produced by the star’s
mass feeding the black hole creates a luminous flare, which all-sky surveys
like ASAS-SN can observe. While such events have been detected far away from
Earth, finding one relatively close by is rare. ASASSN-23bd, as the event is
known, is a remarkable nearby TDE, making it an excellent subject for further
study.
The astronomers found that ASASSN-23bd was
unlike many other TDEs they had observed before:
◦ It emitted much less energy than
previous TDEs
◦ It was the closest TDE [1]
discovered using visible light
◦ Its change in brightness happened
about twice as fast as most TDEs
◦ ASASSN-23bd is in a unique
category of objects known as low luminosity and Fast TDEs
◦ luminosity and Fast TDEs
Source: University of Hawaii at Manoa
