What are tidal disruption events? Are they different ways to detect them?
When a star gets too close to a supermassive black hole, chaos ensues. Gravity pulls the star apart, scattering its remains and creating one of the brightest, most energetic events in the universe: a tidal disruption event (TDE) (1). While these dramatic “black hole’s lunches” are rare, astronomers at the Massachusetts Institute of Technology (MIT) recently discovered 18 new occurrences, more than doubling the known catalog of TDEs (2). The researcher’s secret weapon? Infrared light (3).
MIT scientists have identified 18 new tidal disruption events (TDEs) https://news.mit.edu/2024/astronomers-spot-eighteen-black-holes-gobbling-nearby-stars-0129
After the star ventures too close to the black hole, its gravity stretches it into a long stream of gas in a process called spaghettification, eventually ripping it apart. The debris forms an accretion disk, a rotating ring of gas and dust swirling around the black hole, which releases a powerful burst of energy across the electromagnetic spectrum (1).
Led by Megan Masterson, an MIT team made this breakthrough by using data from NASA’s Near-Earth Object Wide-field Infrared Survey Explorer mission, a space telescope designed to observe the sky in infrared light. By analyzing archival observation with an algorithm developed by co-author Kishalay DE, the team identified patterns of infrared emissions that are likely signs of infrared radiation bursts—characteristics of TDEs. The team then cross-referenced the bursts with a catalog of known nearby galaxies, determining that the infrared bursts could be traced back to 1000 possible galaxies. After ruling out the possibility that the signal came from a supernova or an active galactic nucleus, the team analyzed the remaining bursts looking for an infrared pattern that is characteristic of TDEs. This pattern includes a sharp spike, reflecting the process in which the black hole ripping apart the star suddenly heats up surrounding dust to approximately 1000 Kelvins before gradually cooling down (6). They identified 18 clear TDE signals, including the closest one ever observed—130 million light-years from Earth (4).
Previously, most TDEs were detected in rare post-starburst galaxies, where the lack of dust made X-ray and optical emission easier to spot (5). However, these galaxies represent only a small fraction of the universe. By using infrared light, the MIT team was able to detect TDEs in a much wider variety of galaxies. This new method also sheds light on the missing energy problem (2,6). Theoretical models predicted that TDEs should emit more energy than the observed amount in optical and X-ray bands. The MIT team’s findings suggest that dust in these galaxies absorbs and re-emits much of this energy, resolving the discrepancy.
With more TDEs detected, researchers can better estimate how often these events occur: about 50,000 years per galaxy (2). Additionally the ability to observe TDEs in dusty galaxies opens up new avenues for studying supermassive black holes in environments previously thought to be inaccessible. This groundbreaking work paves the way for future studies using infrared surveys, offering a deeper understanding of the universe’s most mysterious phenomena.
Sources:
- Cendes, Y. (2021, December 8). How do black holes swallow stars? Astronomy Magazine. https://www.astronomy.com/science/how-do-black-holes-swallow-stars/
- Chu, J. (2024, January). Astronomers spot 18 black holes gobbling up nearby stars. MIT News | Massachusetts Institute of Technology. https://news.mit.edu/2024/astronomers-spot-eighteen-black-holes-gobbling-nearby-stars-0129
- Lea, R. (2024, January 31). Astronomers witness 18 ravenous black holes ripping up and devouring stars. Space.com; Space. https://www.space.com/black-holes-tidal-disruption-events-spaghettifying-stars
- Ghoshal, S. (2025, January 19). Notes on the fragile Malayali male ego. Mint. https://www.livemint.com/mint-lounge/art-and-culture/caste-system-gender-politics-kerala-social-reform-11737090517617.html
- 18 supermassive black holes found devouring stars, according to MIT study – The Boston Globe. (2016). BostonGlobe.com. https://www.bostonglobe.com/2024/02/02/metro/black-holes-mit-study/
- Masterson, M., De, K., Panagiotou, C., Kara, E., Iair Arcavi, Eilers, A.-C., Frostig, D., Suvi Gezari, Iuliia Grotova, Liu, Z., Malyali, A., Meisner, A. M., Merloni, A., Newsome, M., Rau, A., Simcoe, R. A., & Sjoert van Velzen. (2024). A New Population of Mid-infrared-selected Tidal Disruption Events: Implications for Tidal Disruption Event Rates and Host Galaxy Properties. The Astrophysical Journal, 961(2), 211–211. https://doi.org/10.3847/1538-4357/ad18bb