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Tue Jun 30, 2020, 11:39 PM

Giant star pulls off vanishing act. Did it become a black hole or was it all an illusion?


By Elizabeth Howell 17 hours ago



An artist's depiction of what the bright blue variable star in the galaxy Kinman Dwarf might have looked like before its sudden disappearance.
(Image: © ESO/L. Calçada)

An unstable massive star has suddenly vanished from view, and astronomers aren't sure if it collapsed into a black hole or is playing peek-a-boo behind galactic dust.

The star was too far away to spot on its own, but it showed up in the spectrum, or light signature, of the Kinman Dwarf galaxy, which is some 75 million light-years away from Earth. The spectrum showed that the distant galaxy contained a late-stage blue variable star that is 2.5 million times brighter than the sun. Stars of this type are known to be temperamental, with dramatic shifts in their spectra and luminosity (inherent brightness).

The blue variable star's signature appeared in observations gathered between 2001 and 2011. The European Southern Observatory's (ESO's) Very Large Telescope, however, couldn't find the star during two separate observing 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.

What's more, the Kinman Dwarf showed no signs of a supernova, or star explosion, during the intervening years — leading the team to speculate the star may have collapsed directly into a black hole, instead of going supernova first.

More:
https://www.space.com/giant-star-disappearance-black-hole-mystery.html

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Reply Giant star pulls off vanishing act. Did it become a black hole or was it all an illusion? (Original post)
Judi Lynn Jun 30 OP
abqtommy Jun 30 #1
Jeebo Jul 1 #2

Response to Judi Lynn (Original post)

Tue Jun 30, 2020, 11:53 PM

1. How are we supposed to figure these things out when it takes 75 million years for the light

from this star to reach us and the source disappears before we even realize it was there? This makes
achieving world peace and universal health care very doable things...

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Response to Judi Lynn (Original post)

Wed Jul 1, 2020, 12:08 AM

2. Have you read "Pandora's Star" by Peter F. Hamilton?

One of the best, one of the most imaginative and original science fiction novels I've ever read. There is a star, a much closer one, that suddenly disappears, and astronomers wonder why. What could make a whole sun just suddenly blink out? Turns out, it was an extraterrestrial race who were building a shell around their home star to capture 100 percent of its energy, and when they completed the shell was when it blinked out from our perspective. You perhaps will notice that I didn't call them an "extraterrestrial civilization" but an "extraterrestrial race". This is because they weren't particularly civilized, which turned out later in the novel to be a HUGE problem for us.

I've got lots of time for reading. Might re-read "Pandora's Star" and its sequel "Judas Unchained". It's been a while.

-- Ron

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