The closest known black hole to Earth has been discovered by astronomers using the Gemini International Observatory, operated by NSF’s NOIRLab.
A dormant stellar-mass black hole has been confirmed to exist in the Milky Way for the first time. With only 1600 light years between it and Earth, it is a fascinating research topic to improve our knowledge of the development of binary systems.
The most extreme things in the universe are black holes. All huge galaxies presumably have supermassive versions of these unfathomably dense objects at their centers.
There are about 100 million stellar-mass black holes in the Milky Way alone, which are significantly more widespread and weigh five to a hundred times more than the Sun. Unlike dormant black holes, which don’t flash brightly in X-rays because they’re consuming matter from a nearby stellar companion, only a small number have been confirmed so far, and nearly all of them are “active.”
The closest black hole to Earth has been named Gaia BH1 by astronomers using the Gemini North Telescope on the island of Hawaii, one of the twin telescopes of the Gemini International Observatory, which is operated by the NOIRLab of the NSF.
It is three times closer to Earth than the previous record holder, an X-ray pair in the constellation Monoceros. This dormant black hole is about 10 times larger than the Sun and is located about 1600 light-years away in the constellation Ophiuchus. Exquisite studies of the motion of the black hole’s partner, a Sun-like star that orbits the black hole at roughly the same distance as Earth orbits the Sun, have led to this new discovery.
“Take the solar system, put a black hole where the Sun is, and the Sun where the Earth is, and you get this system,” explained Kareem El-Badry, an astrophysicist at the Center for Astrophysics | Harvard & Smithsonian and the Max Planck Institute for Astronomy, and the lead author of the paper describing this discovery.
“While there have been many claimed detections of systems like this, almost all of these discoveries have subsequently been disproved. This is the first unambiguous detection of a Sun-like star over a wide orbits a stellar-mass black hole in our Galaxy.”
The few stellar-mass black holes that have been discovered have been revealed by their energizing interactions with a companion star, despite the fact that there are likely millions of them roaming the Milky Way. Superheated material from a nearby star heads toward the black hole, where it produces intense X-rays and jets of material. When a black hole is dormant (i.e. not actively feeding), it simply blends into its surroundings.
“I have searched for dormant black holes over the past four years using a wide range of datasets and methods,” El-Badry said. “My previous attempts – and those of others – have revealed a menagerie of binary systems masquerading as black holes, but this is the first time the search has paid off.”
Data from the European Space Agency’s Gaia spacecraft was first examined by researchers to determine the potential presence of a black hole in the system. Gaia captured the tiny deviations in the star’s velocity caused by a huge invisible object.
El-Badry and his team used the Gemini Multi-Object Spectrograph instrument on Gemini North to study the system in more detail. This device accurately determined the orbital period of the companion star by measuring the velocity of the companion star as it orbited the black hole. The team was able to identify the central body as a black hole about 10 times more massive than our Sun thanks to Gemini tracking observations, which were key to constraining the orbital speed and, therefore, the masses of the two components in the binary system.
“Our Gemini tracking observations have confirmed beyond reasonable doubt that the binary contains a normal star and at least one dormant black hole,” El-Badry explained. “We were unable to find any plausible astrophysical scenario that could explain the system’s observed orbit that does not involve at least one black hole.”
Since they only had a small window to make their follow-up observations, the team relied not only on Gemini North’s excellent observing capabilities, but also on Gemini’s ability to provide short-term data. prior notice.
“When we had the first indications that the system contained a black hole, we only had a week before the two objects were at the closest distance in their orbits. Measurements at this stage are essential to make accurate mass estimates in a binary system,” he added. said El-Badry. “Gemini’s ability to provide observations over a short period of time was essential to the success of the project. If we had missed this narrow window, we would have had to wait another year.”
The unique configuration of the Gaia BH1 system is difficult to explain using astronomers’ current concepts of the evolution of binary systems. The progenitor star, which later evolved into the newly discovered black hole, would have had a mass at least 20 times that of the Sun.
It would have had a short lifespan of a few million years. If the two stars had formed simultaneously, this huge star would have quickly evolved into a supergiant, swelling and swallowing the second star before it had a chance to grow into a true main-sequence star like our Sun, which burns light. ‘hydrogen.
It is not at all clear how the solar-mass star could have survived this episode, ending up as a seemingly normal star, as observations of the black hole binary indicate. The theoretical models that allow for survival all predict that the solar-mass star should have ended up in a much tighter orbit than is actually observed.
This could indicate that there are significant gaps in our understanding of the formation and evolution of black holes in binary systems, and also suggests the existence of a yet unexplored population of dormant black holes in binaries.
“Interestingly, this system is not easily adapted to standard binary evolution models,” El-Badry concluded. “It raises a lot of questions about how this binary system formed, as well as how many of these dormant black holes there are.”
(Except for the title, this story has not been edited by NDTV staff and is published from a syndicated feed.)
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