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Gaaark [soylentnews.org] writes:

https://phys.org/news/2018-06-mystery-milky-supermassive-black-hole.html [phys.org]

Astronomers have discovered several bizarre objects at the Galactic Center that are concealing their true identity behind a smoke screen of dust; they look like gas clouds, but behave like stars.

"These compact dusty stellar objects move extremely fast and close to our Galaxy's supermassive black hole. It is fascinating to watch them move from year to year," said [Anna] Ciurlo. "How did they get there? And what will they become? They must have an interesting story to tell."

"We started this project thinking that if we looked carefully at the complicated structure of gas and dust near the supermassive black hole, we might detect some subtle changes to the shape and velocity," said Randy Campbell, science operations lead at Keck Observatory. "It was quite surprising to detect several objects that have very distinct movement and characteristics that place them in the G-object class, or dusty stellar objects."

GCOI [UCLA's Galactic Center Orbits Initiative] thinks that these G-objects are the result of stellar mergers—where two stars orbiting each other, known as binaries, crash into each other due to the gravitational influence of the giant black hole. Over a long period of time, the black hole's gravity alters the binary stars' orbits until the duo collides. The combined object that results from this violent merger could explain where the excess energy came from.

"This is what I find most exciting," said Andrea Ghez, founder and director of GCOI. "If these objects are indeed binary star systems that have been driven to merge through their interaction with the central supermassive black hole, this may provide us with insight into a process which may be responsible for the recently discovered stellar mass black hole mergers that have been detected through gravitational waves."

What makes G-objects unusual is their "puffiness." It is rare for a star to be cloaked by a layer of dust and gas so thick that astronomers do not see the star directly. They only see the glowing envelope of dust. To see the objects through their hazy environment, Campbell developed a tool called OSIRIS-Volume Display (OsrsVol).

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