Astronomers utilizing ESO’s Very Giant Telescope Interferometer (VLTI) have captured a zoomed-in picture of the dust-enshrouded purple supergiant star WOH G64.
This picture, taken by the GRAVITY instrument on ESO’s Very Giant Telescope Interferometer, reveals the purple supergiant WOH G64. Picture credit score: ESO / Ohnaka et al., doi: 10.1051/0004-6361/202451820.
WOH G64 is positioned roughly 160,000 light-years away within the constellation of Dorado.
Often known as IRAS 04553-6825, 2MASS J04551048-6820298 or TIC 30186593, the star is a part of the Giant Magellanic Cloud, one of many small galaxies that orbits our Milky Manner Galaxy.
With a dimension roughly 2,000 instances that of our Solar, WOH G64 is assessed as a purple supergiant.
“We found an egg-shaped cocoon intently surrounding the star,” mentioned Dr. Keiichi Ohnaka, an astrophysicist at Andres Bello College.
“We’re excited as a result of this can be associated to the drastic ejection of fabric from the dying star earlier than a supernova explosion.”
“Whereas astronomers have taken about two dozen zoomed-in pictures of stars in our Milky Manner Galaxy, unveiling their properties, numerous different stars dwell inside different galaxies, so far-off that observing even considered one of them intimately has been extraordinarily difficult — up till now.”
An artist’s reconstruction of the purple supergiant WOH G64. Picture credit score: ESO / L. Calçada.
Dr. Ohnaka and colleagues had lengthy been serious about WOH G64.
Again in 2005 and 2007, they used VLTI to study extra in regards to the star’s options, and carried on learning it within the years since. However an precise picture of the star had remained elusive.
For the specified image, they needed to await the event of one of many VLTI’s second-generation devices, GRAVITY.
After evaluating their new outcomes with different earlier observations of WOH G64, they have been shocked to search out that the star had grow to be dimmer over the previous decade.
“We’ve discovered that the star has been experiencing a major change within the final 10 years, offering us with a uncommon alternative to witness a star’s life in actual time,” mentioned Professor Gerd Weigelt, an astronomer on the Max Planck Institute for Radio Astronomy.
Of their ultimate life phases, purple supergiants like WOH G64 shed their outer layers of fuel and mud in a course of that may final 1000’s of years.
“This star is likely one of the most excessive of its type, and any drastic change might convey it nearer to an explosive finish,” mentioned Dr. Jacco van Loon, director of Keele Observatory at Keele College.
“These shed supplies may additionally be chargeable for the dimming and for the sudden form of the mud cocoon across the star,” the astronomers mentioned.
The brand new picture reveals that the cocoon is stretched-out, which shocked the researchers, who anticipated a distinct form based mostly on earlier observations and pc fashions.
They consider that the cocoon’s egg-like form might be defined by both the star’s shedding or by the affect of a yet-undiscovered companion star.
Because the star turns into fainter, taking different close-up footage of it’s turning into more and more tough, even for VLTI.
Nonetheless, deliberate updates to the telescope’s instrumentation, resembling the long run GRAVITY+promise to vary this quickly.
“Related follow-up observations with ESO devices can be essential for understanding what’s going on within the star,” Dr. Ohnaka mentioned.
The crew’s paper was printed within the journal Astronomy & Astrophysics.
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Ok. Ohnaka et al. 2024. Imaging the innermost circumstellar atmosphere of the purple supergiant WOH G64 within the Giant Magellanic Cloud. A&A 691, L15; two: 10.1051/0004-6361/202451820