A system of Ohio State University telescopes across the world alerted researchers that a black hole was destroying a star 375 million light years away. Researchers were able to focus satellites on the event to learn more about the physics behind what's known as tidal disruption events.

The star passed too close to the black hole.

Extreme gravity caused the star to splinter apart and unfurl like a rope. The tail of the gas emissions spun out into space.

The incident is what is known as a tidal disruption event. Such events happen about just once every 10,000 to 100,000 years in galaxies the size of the Milky Way. This event was captured early on by a system of 20 robotic telescopes across the globe known as the All-Sky Automated Survey for Supernovae (ASAS-SN) that is headquartered at Ohio State University.

“The galaxy is about 375 million light years away. So this happened about 375 million years ago, in reality. And the light has just reached us now,” said Tom Holoien, a Carnegie Fellow and post-doctoral researcher at Carnegie Observatories in California. Holoien earned his Ph.D at Ohio State.

>> Video: NASA animation showing a black hole shredding a star

The findings were published Thursday in the Astrophysical Journal. The event, named ASASSN-19bt, took place in the Volans constellation. The destroyed star may have been about the same size as the sun, according to an Ohio State release.

Thanks to the university's series of telescopes, Holoien was alerted by the system on Jan. 29 while he as at a Las Campanas Observatory in Chile. He focused telescopes there and coordinated other satellites to capture the event.

NASA’s Transiting Exoplanet Survey Satellite (TESS), which launched in 2018, was built to find new planets. It was already focused on the area and was taking images for a portion of the sky every 30 minutes for a year. Detailed data from TESS in space showed signs of the event up to 10 days before it happened.

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“We've seen TDs before, we've never seen one this early with this — nearly as good as this data set is” said Patrick Vallely, a co-author of the study and National Science Foundation graduate research fellow at Ohio State. “There’s 40ish known ones.”

A few are found each year, but many lack the details of this event. The events can vary depending on factors including the size of the star and how close it orbits next to a black hole. For example, in some cases, the black hole will completely absorb the star.

“We really did kind of hit the lottery with this one — to be able to catch it early, and to document everything as it's happening,” Holoien said.

The additional details can help researchers learn more about how the events form and play out.

NASA’s Neil Gehrels Swift Observatory satellite with its UV/optical telescopes measured ultraviolet light. The events burn about 10 times as hot as the sun’s surface.

“They emit most strongly in ultraviolet wavelengths. And if we want to constrain the temperature with how bright it is, and how big it is, we need to have the UV data in order to have that constraint on the temperature,” Holoien said. “We actually saw this early drop in the temperature that we've never seen before ... That was something totally new that we didn't really expect to see. So it gave us sort of a new set of observations to help us refine our theoretical models going forward.”

There was a 1% to 3% chance of catching this event. Some of it came down to luck with satellites like TESS already trained on locations at the right time.

“They’re fairly rare. Imagine standing on top of the LeVeque tower and dropping a marble off of it into a manhole. It’s that's kind of the problem,” said Chris Kochanek, professor of astronomy at Ohio State.

The event itself can last for months.

"They rise to peak in several weeks to a month, then fade more slowly -- some have been tracked for more than one year -- the limit on that is more that they just get too faint then that they come to an abrupt end," he said. "In the simplest theoretical model they just steadily fade as time passes."

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