Login | October 19, 2019

OSU telescope network aids in NASA’s glimpse of a star-shredding black hole galaxies away

KEITH ARNOLD
Special to the Legal News

Published: October 8, 2019

Not so long ago, in a galaxy some 375 million light years away, Ohio State University scientists were able to catch an astronomical phenomenon of grand proportions via NASA satellite - a black hole ripping a star to shreds.

Also known as a tidal disruption event, the phenomenon was captured as a result of a worldwide network of robotic telescopes headquartered at Ohio State tracking the progress of NASA's Transiting Exoplanet Survey Satellite, or TESS.

"We've been closely monitoring the regions of the sky where TESS is observing with our All-Sky Automated Survey for Supernovae (ASAS-SN) telescopes, but we were very lucky with this event in that the patch of the sky where TESS is continuously observing is small, and in that this happened to be one of the brightest tidal disruption events we've seen," said Patrick Vallely, a co-author of the study and National Science Foundation Graduate Research Fellow at Ohio State. "Due to the quick ASAS-SN discovery and the incredible TESS data, we were able to see this TDE much earlier than we've seen others - it gives us some new insight into how TDEs form."

Tidal disruption events happen when a star gets too close to a black hole, a press release detailed.

Depending on a number of factors, including the size of the star, the size of the black hole and how close the star is to the black hole, the black hole can either absorb the star or tear it apart into a long, spaghetti-like strand.

"TESS data let us see exactly when this destructive event, named ASASSN-19bt, started to get brighter, which we've never been able to do before," said Carnegie Fellow Thomas Holoien, who earned his doctorate degree at Ohio State. "Because we discovered the tidal disruption quickly with the ground-based ASAS-SN, we were able to trigger multiwavelength follow-up observations in the first few days.

"The early data will be incredibly helpful for modeling the physics of these outbursts."

According to Ohio State astronomy professor Chris Kochanek, professor of astronomy at Ohio State, tidal disruptions are rare, occurring once every 10,000 to 100,000 years in a galaxy the size of the Milky Way.

Supernovae, by comparison, happen every 100 years or so. Scientists have observed about 40 tidal disruption events throughout history with the ASAS-SN seeing a few each year.

The events are rare, the professor continued, mostly because stars need to be very close to a black hole - about the distance Earth is from our own sun - in order to create one.

"Imagine that you are standing on top of a skyscraper downtown, and you drop a marble off the top, and you are trying to get it to go down a hole in a manhole cover," he said. "It's harder than that."

Astronomers from the Carnegie Observatories, Ohio State and other institutions published their findings last week in The Astrophysical Journal.

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