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NASA's TESS Mission Finds Eerie Star-Shredding Black Hole

NASA's planet-hunting Transiting Exoplanet Survey Satellite (TESS) has observed a black hole ripping apart a star for the first time.

The star-destroying event involving a cataclysmic phenomenon dubbed a tidal disruption event was observed by TESS on January 21. Follow-up observations by NASA's Neil Gehrels Swift Observatory and other skywatching facilities have created the most detailed view of the early moments of this turbulent, tidal disruption event. A paper detailing researchers' findings was published in The Astrophysical Journal on Thursday.

“TESS data let's see exactly when this destructive event, named ASASSN-19bt, started to get brighter, which we had never been able to do before. Because we quickly identified tidal disruption with the ground-based All-Sky Automated Survey for Supernovae (ASAS-SN), we were able to trigger multi-wavelength follow-up observations in the first few days, ”said Thomas Holoien, a Carnegie Fellow at the Carnegie Observatories in Pasadena, California. "The early data will be extremely useful for modeling the physics of these outbursts."

When TESS first spotted ASASSN-19bt earlier this year, it took over a week before the event was bright enough for ASAS-SN, a worldwide network of 20 robotic telescopes at Ohio State University in Columbus, Ohio, to detect it, NASA said in a press release. The satellite only transmits data to our planet every 14 days and once received, the information is processed at NASA's Ames Research Center in California. The first TESS data on tidal disruption event was not available until March 13. Fortunately, tidal disruption took place in TESS's southern continuous viewing area and ASASSN-19bt's location enabled Holoien and his team to monitor the event across many sectors.

"The early TESS data allow us to see light very close to the black hole, much closer than we could have seen before," said Patrick Vallely from OSU. "They also showed us that the ASASSN-19bt's rise in brightness was very smooth, which helps tell us that the event was a tidal disruption and not another type of outburst, such as from the center of a galaxy or a supernova."

Holoien and his colleagues used Swift UV data to determine that the temperature dropped by roughly 50 percent, from roughly 71,500 to 35,500 degrees Fahrenheit, over a few days. According to Holoien, the first time an early temperature decrease has been observed in a tidal disruption, although some theories have predicted this activity.

Astronomers believe that the supermassive black hole that produced the ASASSN-19bt weighs about six million times the mass of the sun and sits at the heart of a galaxy called 2MASX J07001137-6602251, which is located about 375 million light-years away in the constellation Volans.

According to NASA, tidal disruptions often occur, and they take place every 10,000 to 100,000 years in a galaxy equal in size to the Milky Way. Astronomers have observed only about 40 tidal disruptions so far and some scientists predicted that TESS would only see maybe one or two during its initial 24-month mission. Scientists are still trying to determine why tidal disruptions produce a lot of UV emission and only a handful of X-rays.

"For TESS to observe the ASASSN-19bt so early in its tenure, and in the continuous viewing area where we could watch it for so long, is really extraordinary," said Padi Boyd, the TESS project scientist at Goddard. "Future collaborations with observatories around the world and in orbit will help us learn even more about the different outbursts that light up the cosmos."

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