A supermassive black hole destroyed a star that got too close

Artistic illustration of the event ASASSN-14li with the accretion disk around the black hole and part of the materials from the shredded star forming a tail (Image Spectrum: NASA/CXC/U.Michigan/J.Miller et al.; Illustration: NASA/CXC/M.Weiss)
Artistic illustration of the event ASASSN-14li with the accretion disk around the black hole and part of the materials from the shredded star forming a tail (Image Spectrum: NASA/CXC/U.Michigan/J.Miller et al.; Illustration: NASA/CXC/M.Weiss)

An article published in the journal “Science” describes the observations of a supermassive black hole with a mass a few millions times that of the Sun that destroyed a star with the consequent formation of a jet of matter moving at speeds close to that of light. This event, called ASASSN-14li, had already been described a few weeks ago in another study whose results were published in the journal “Nature”.

The supermassive black hole responsible for this Tidal Disruption Event (TDE) is located in the center of the galaxy PGC 043234, about 290 million light years from Earth. In November 2014, the All-Sky Automated Survey for Supernovae (ASAS-SN) survey discovered it calling it ASASSN-14li and at that point specific observations started.

A team led by Dr. Jon Miller of the University of Michigan has been using NASA’s Chandra and Swift and ESA’s XMM-Newton space telescopes to observe the X-ray emissions from ASASSN-14li. The results of this research were published in “Nature”.

A team led by Sjoert van Velzen of the Johns Hopkins University used radio telescopes to observe the radio emission from ASASSN-14li. In particular, this research focused on the jets emitted in the course of that kind of event. The results of this research were published in “Science”. This team compared their findings with another one from Harvard who observed the event with other radio telescopes.

Events such as ASASSN-14li are caused when a star gets too close to a black hole. Gravitation forces are so intense that even a star gets destroyed. The consequence is that some of the material that composed the star get swallowed by the black hole but another part gets launched into space at speeds approaching that of light.

In these cases, the remains of the star get heated to such a temperature that they emit electromagnetic radiation in various bands that include radio waves and X-rays. For this reason, it was important that the different groups of scientists observed the event ASASSN-14li with different instruments that provided information that can be combined.

ASASSN-14li is the closest Tidal Disruption Event observed in the last decade. Being able to observe it with the telescopes currently available, both ground-based and in space, allowed to obtain much more information on this type of cosmic catastrophes. The astronomers hope to discover more of them to better understand how black holes influence the areas of space around them.



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