A massive unstable star has suddenly disappeared from view, and astronomers are not sure if it collapsed in a dungeon or is playing peek-a-boo behind the galactic dust.
The star was too far away to detect on its own, but it appeared on the spectrum, or light signature, of the dwarf Kinman galaxy, which is about 75 million light-years from Earth. The spectrum showed that the distant galaxy contained a late stage blue variable star that’s 2.5 million times brighter than the sun. Stars of this type are known to be temperamental, with dramatic changes in their spectra and luminosity (inherent brightness).
The signature of the blue variable star appeared in observations collected between 2001 and 2011. The European Southern Observatory (ESO) Very large telescopeHowever, he was unable to find the star during two separate observation sessions in 2019 with different spectrograph devices. Those instruments included the Echelle spectrograph for Rocky Exoplanet and stable spectroscopic observations (ESPRESSO) and the X-shooter.
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Furthermore, the dwarf Kinman showed no signs of a supernova, or star burst, during the intervening years, leading the team to speculate that the star may have directly collapsed into a black hole, rather than become a supernova first.
“We were surprised to discover that the star had disappeared,” said lead researcher Andrew Allan, Ph.D. student at Trinity College Dublin in Ireland, said in an ESO statement. If the star has gone directly from being a star to being a black hole, Allan added, “this would be the first direct detection of a monstrous star ending its life this way.”
To learn more, the team analyzed old data collected by X-shooter and VLT’s Ultraviolet and Visual Echelle Spectrograph between 2002 and 2009. (ESPRESSO was only installed in 2016). Other telescopes were also used for historical study; Between VLT spectrographs and these other observatories, astronomers easily confirmed the presence of the now-missing star in the oldest observations.
Searching the file also revealed new information. The star, according to old data, could have been making a strong explosion That ended some time after the scientists’ last observation in 2011. The blast would have produced a high rate of mass loss and would have caused the star’s luminosity to temporarily increase.
It is what happened after this explosion that has intrigued astronomers. If the star actually collapsed into a black hole, this is an unusual life path for a late stage. blue Star like that of the dwarf Kinman. Typically, the sequence would see the star explode into a supernova first, before the event’s strong gravity pushes it toward a black hole.
One possible explanation, astronomers think, is that perhaps the star lost so much mass that it became less luminous and is now partially hidden by dust in the galaxy.
Astronomers plan to track their work with a more powerful observatory, when it’s ready. Those Extremely large telescope It will have a single 127-foot (39-meter) mirror, compared to the combined aperture of the 107-foot (32-meter) mirror VLT in four telescopes. That would make it large enough to detect individual stars in distant galaxies like the Dwarf Kinman. The new telescope is slated to see first light in 2025.
A study Based on the research, it was published Tuesday (June 30) in the Monthly Notices of the Royal Astronomical Society.
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