Black hole records have been rewritten.
A black hole with about 10 times the mass of the Sun is lurking just 1,560 light-years away from Earth, new research reports. That’s about double his previous Proximity Champion.
A newly discovered object, a stellar-mass black hole named Gaia BH1, exists in a binary star system whose other members are Sun-like stars. This star is as far from its black brethren as the Earth is from the Sun, making Gaia BH1 very special.
“While there have been many claimed detections of systems like this, almost all these discoveries have subsequently been refuted,” study lead author Kareem El-Badry, of the Harvard-Smithsonian Center for Astrophysics in Massachusetts and the Max Planck Institute for Astronomy in Germany, said in a statement. “This is the first unambiguous detection of a sunlike star in a wide orbit around a stellar-mass black hole in our galaxy.”
Astronomers think that our Milky Way galaxy harbors about 100 million stellar-mass black holes, light-gobbling objects that are five to 100 times more massive than the sun.
Their small size makes these bodies relatively hard to detect, however, especially by telescope. (Gravitational-wave detectors have had more success recently, finding evidence of mergers involving these objects.) And the ones that scientists do see tend to be “X-ray binaries,” black holes that pull material from a companion star into an accretion disk around themselves. This fast-orbiting dust and gas emits X-rays, high-energy light that some powerful telescopes can observe. However, not all stellar-mass black holes inhabiting binary systems are actively supplying energy. Finding these dormant objects is even more difficult and requires different strategies.
Researchers used one such alternative technique in a new study. They were looking at data collected by the European Space Agency’s (ESA) Gaia spacecraft that accurately map the positions, velocities, and orbits of about two billion Milky Way stars.
One of these stars is a member of Gaia BH1. Small irregularities can be seen in its movement. This indicates that something huge and invisible is being pulled by gravity.
Gaia’s measurements suggested that a black hole could be its tug, but scientists needed more data to know for sure. There they studied the stars using a variety of ground instruments, including the Gemini North and Keck 1 telescopes in Hawaii and the Magellan Clay and his MPG/ESO telescopes in Chile.
These follow-up observations, combined with Gaia data, allowed the team to make detailed measurements of the system. The invisible object contains the mass of 10 suns and orbits the system’s center of mass about once every 186 Earth days. And it must be a black hole.
“Following observations of Gemini confirm beyond reasonable doubt that the binary contains a regular star and at least one dormant black hole,” said El-Badry. I’m here. “We were unable to find a plausible astrophysical scenario that could explain the observed orbits of a system that does not contain at least one black hole.”
For example, if Gaia BH1’s invisible object is a star, it will be much brighter than its companion, making it easier to see. However, none of the team’s observations indicated there was a second star for her in the system.
The Gaia BH1 system is attractive not only because of its relative proximity. (Indeed, it’s closer to how the universe works. The Milky Way’s famous spiral disk is about 100,000 light-years across.) The researchers determined how stars and black holes got to where they are today. Is not …
Gaia BH1’s mass suggests that the dead and born star must have been huge – at least about 20 times her solar mass. Such giants live only a few million years and become very bloated before giving up ghosts.
Modeling work suggests that such bloating likely destroyed the companion before it had a chance to evolve into a Sun-like star (if the two were born at the same time). Alternatively, had it survived, it would have landed in a much narrower orbit than it currently is, the researchers said.
“What’s interesting is that the system isn’t easily adaptable from standard binary evolution models,” says El Badry. “It raises a lot of questions about how this binary system came about and how many of these dormant black holes are out there.”
A new survey was released today (November 20). 4) in der Zeitschrift Monthly Notices of the Royal Astronomical Society.
