High School Students Help Discover Star Being Devoured by Black Hole

High school students have helped discover a star being eaten by a nearby black hole after they looked through decades of old telescope data.

The cosmic event was first noticed by astronomers thanks to the efforts of Ginevra Zaccagnini and Jackson Codd, both high school interns from Cambridge, Massachusetts. The two interns had been working with Vikram Ravi, assistant professor of astronomy at Caltech, in 2018 and 2019 while he was at Harvard University.

Looking through archived data at the National Radio Astronomy Observatory's (NRAO's) Karl G. Jansky Very Large Array (VLA) in New Mexico, the students noticed that an object in space known as J1533+2727 was bright in the mid-90s but had faded by 2017.

Looking back through other datasets the astronomy team learned that the same object had been even brighter in the 1980s.

Based on the evidence, Ravi and his team concluded that J1533+2727 was something called a Tidal Disruption Event or TDE—the result of a star straying too close to a black hole and getting drawn in.

The black hole is thought to be a supermassive type, located at the heart of a galaxy 500 million light-years away from Earth. As it devoured the star, a radio jet was expelled traveling at nearly the speed of light.

Generally, stars will orbit black holes without getting into trouble. Sometimes, when a star gets too close, the black hole's strong gravity will tear the star apart, stretching it out into a thin stream that falls into the black hole.

These events are so energetic that they can temporarily be brighter than the entire galaxy in which they occur.

"This is a really messy process," Ravi said in a Caltech press release. "The stars don't go quietly!"

As these stars are devoured, their remains glow with powerful light or other electromagnetic radiation that can be detected by telescopes here on Earth. The process is also sometimes dubbed spaghettification.

TDEs have become a relatively new means of figuring out how black holes work, literally shedding light onto extreme regions of space.

There have only been 100 recorded TDEs to date, according to Caltech, and the discovery of J1533+2727 is thought to be only the second one detected via radio waves—the first being reported back in 2020.

The most recent study by Ravi and colleagues, titled "The radio afterglow of a decades-old tidal disruption event," has been accepted for publication in The Astrophysical Journal having been submitted in February 2021. As of Wednesday, it was available on the pre-print server arXiv.

The study concludes that ongoing radio surveys could uncover more star-devouring events in future.

In 2021, scientists reported a reverse event in which a star absorbed a black hole as opposed to the other way around. However, the process resulted in the star exploding and the black hole standing alone.

Black hole eating star
An illustration of a black hole eating a star with a stock image of some high school students edited in. Using archival telescope data, students identified one such event along with a team of astronomers. NASA/JPL-Caltech/jacoblund/Getty