June 19, 2024

One Star Could Answer Many Unsolved Questions About Black Holes

A supermassive black hole (SMBH) likely lives at the center of the Milky Way, and in the centers of other galaxies like it. Its never ever been seen. It was found by enjoying a cluster of stars near the galactic center, called S stars.
S stars motions showed the presence of an enormous object in the Milky Ways center and the clinical community primarily concurred that it should be an SMBH. Its named Sagittarius A *.
Some researchers wonder if it actually is a black hole. And one of the S stars could answer that concern and a few others about black holes.

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A supermassive black hole (SMBH) likely lives at the center of the Milky Way, and in the centers of other galaxies like it. It was found by seeing a cluster of stars near the galactic center, called S stars.
Theyve collected accurate astrometric data for the group of stars, and the measurements of the stars positions and motions around the galactic center have revealed that theres a huge item there. One specific star in the group– named S2 (or S0-2)– could help astronomers figure out more plainly the nature of that enormous things.
Artists impression of the orbits of 3 of the stars really close to the supermassive black hole at the center of the Milky Way.

Researchers have been keeping an eye on and studying the S stars for over 20 years. Theyve gathered precise astrometric information for the group of stars, and the measurements of the stars positions and motions around the galactic center have shown that theres an enormous things there. One specific star in the group– called S2 (or S0-2)– might help astronomers determine more plainly the nature of that huge item.
A new research study letter is taking a close appearance at S2s behaviour and asking a potentially uncomfortable question. The research study is entitled “What does lie at the Milky Way centre? The very first author is C. R. Argüelles from the Fac.
The question of whats at the Milky Ways Center has actually mostly been settled. The press release from the Nobel Prize Organization reads “Reinhard Genzel and Andrea Ghez discovered that a invisible and very heavy things governs the orbits of stars at the centre of our galaxy.
Artists impression of the orbits of three of the stars extremely close to the supermassive black hole at the center of the Milky Way. Credit: ESO/M.
Now theres some unpredictability.
Its possible that the enormous things at the center of our galaxy is actually dark matter. In this case, fermionic dark matter. According to the authors, “It has been recently demonstrated that both, a classical Schwarzschild great void (BH), and a dense concentration of self-gravitating fermionic dark matter (DM) placed at the Galaxy centre, can describe the accurate astrometric information (positions and radial velocities) of the S-stars orbiting Sgr A *.”.
Its not a star, however a cloud of gas called G2. In 2014 G2 passed close by the Milky Ways. They thought that the black hole would tear gas from the cloud, leading to a pronounced brightening from Sgr A * as it accreted mass from G2.
This simulation of a gas cloud passing close to the supermassive black hole at the centre of the galaxy shows the situation in mid-2013. Observations with ESOs Very Large Telescope confirm that the cloud is now so extended that the front part of it has passed the closest point and is taking a trip away from the black hole at more than 10 million km/h, whilst the tail is still falling towards it.
Why werent there any fireworks when G2 passed so near Sgr A *? As it turns out, G2 may not have actually been a gas cloud. Instead, G2 is made up of two parts: a cold cloud of low-mass gas, and a dusty outstanding object. G2s close passage by Sgr A * didnt end up shedding much light on the nature of the things in the galactic.
Back to S2.
As the authors detail, there are two competing designs that can describe the nature of the huge object. And they vary in one essential method. “While the Schwarzschild BH situation predicts a distinct prograde precession for S2, in the DM circumstance it can be either retrograde or prograde …” they compose. Whether S2s precession is either prograde or retrograde depends on the quantity of DM mass inside S2s orbit.
The authors point out that even with all the observations of the S2 star and all of the openly readily available data, scientists are still unable to figure out which of the models are right. But theres a chance to observe S2 turning up that ought to determine if the Milky Ways center is occupied by a black hole or dark matter. ” … upcoming S2 astrometry near to next apocentre passage might possibly develop if Sgr A * is governed by a classical BH or by a quantum DM system,” they compose.
The majority of the matter in the Universe is dark matter, not baryonic matter. Should we sign up surprise when some of the most massive items around may be made of dark matter rather than routine matter? Definitely. Due to the fact that confirming that Sgr A * is not a great void however a mass of dark matter would be a substantial deal.
Well have to see and wait. S2 has an orbital period of 16 years, and the last closest approach to Sgr A * remained in 2018. The next best chance to observe S2 as it goes by Sgr A * is in 2034.
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