Dark holes are the most extreme objects in the universe. Supermassive versions of these unimaginably dense objects likely reside at the centers of all large galaxies.
Stellar-mass black holes— which weigh approximately five in order to 100 times the bulk of the sun— are much more common, with an estimated 100 million in the Milky Way only.
Only a handful have been confirmed to date, however , and nearly all of these are usually “ active” — which means they shine brightly within X-rays as they consume materials from a nearby stellar friend, unlike dormant dark holes which usually do not.
Astronomers using the Gemini North telescope on Hawai’i, one of the cal king telescopes of the International Gemini Observatory, operated by NSF’s NOIRLab, have discovered the nearest black hole to Earth, which the researchers have called Gaia BH1. This dormant black hole weighs regarding 10 times the mass of the sun and is located regarding 1, 600 light-years away in the constellation Ophiuchus, which makes it three times closer to Earth than the previous record holder, a good X-ray binary in the constellation of Monoceros.
The new discovery was permitted by making exquisite observations of the motion of the black hole’s companion, a sun-like star that orbits the dark hole at about the same distance as the Earth orbits sunlight.
“ Consider the solar system , put a dark hole where the sun is definitely, and the sun where the Earth is, and you get this program, ” explained Kareem El-Badry, an astrophysicist at the Center for Astrophysics | Harvard & Smithsonian and the Max Planck Institute for Astronomy, and the lead author from the paper describing this breakthrough.
“ Whilst there have been many claimed detections of systems like this, almost all these discoveries have subsequently already been refuted. This is the first unambiguous detection of a sun-like superstar in a wide orbit around a stellar-mass black hole in our galaxy. ”
Though there are likely countless stellar-mass black holes running around the Milky Way Galaxy, those few that have been recognized were uncovered by their enthusiastic interactions with a companion star . Since material from a nearby celebrity spirals in toward the black hole, it becomes superheated and generates powerful X-rays and jets of material. If a black hole is not actively feeding (i. e., it is dormant) it just blends in with its environment.
“ Trying to find searching for dormant black holes for the last four years using a wide range of datasets and strategies, ” said El-Badry. “ My previous attempts— in addition to those of others— turned up the menagerie of binary systems that masquerade as dark holes, but this is the very first time the search has paid for fruit. ”
The team originally discovered the system as potentially hosting a black hole by examining data from the European Area Agency’s Gaia spacecraft. Gaia captured the minute irregularities within the star’s motion caused by the gravity of an unseen enormous object. To explore the system much more detail, El-Badry and his team turned to the Gemini Multi-Object Spectrograph instrument on Gemini North, which measured the speed of the companion star since it orbited the black hole and provided precise dimension of its orbital period.
The Gemini follow-up observations were crucial to constraining the orbital motion and therefore masses of the two components within the binary system, allowing the team to identify the main body as a black gap roughly 10 times as massive as our sun.
“ The Gemini follow-up observations verified beyond reasonable doubt how the binary contains a normal superstar and at least one heavy black hole, ” elaborated El-Badry. “ We could find no plausible astrophysical situation that can explain the observed orbit of the system it doesn’t involve at least one black hole. ”
The particular team relied not only upon Gemini North’s superb observational capabilities but also on Gemini’s ability to provide data on a tight deadline, as the team had only a short windows in which to perform their followup observations.
“ When we had the first indications that the system contained the black hole, we only had one week before the two objects were at the closest separation in their orbits. Dimensions at this point are essential to make precise mass estimates in a binary system, ” said El-Badry. “ Gemini’s ability to provide fast-turnaround observations was vital to the project’s success. In case we’d missed that narrow window, we would have had to await another year. ”
Astronomers’ current models of the evolution of binary systems are hard-pressed to describe how the peculiar configuration of Gaia BH1 system could have arisen. Specifically, the progenitor star that later turned into the newly detected black hole would have been at least 20 times as huge as our sun.
This means it would have lived only a few million yrs. If both stars formed at the same time, this massive celebrity would have quickly turned into a supergiant, puffing up plus engulfing the other star prior to it had time to turn into a proper, hydrogen-burning, main-sequence superstar like our sun.
It is not at all obvious how the solar-mass star could have survived that episode, winding up as an apparently normal star, as the observations of the dark hole binary indicate. Theoretical models that do allow for success all predict that the solar-mass star should have ended up on a much tighter orbit compared to what is actually observed.
This could indicate there are important gaps in our knowledge of how black holes type and evolve in binary systems, and also suggests the presence of an as-yet-unexplored population of dormant black holes within binaries.
“ It is interesting that this system is not easily accommodated by standard binary evolution versions, ” concluded El-Badry. “ It poses many queries about how this binary program was formed, as well as the number of of these dormant black holes you will find out there. ”
“ As part of a system of space- and ground-based observatories, Gemini North has not only provided strong proof for the nearest black gap to date but also the first pristine black hole system, clean by the usual hot gasoline interacting with the black opening, ” said NSF Gemini Program Officer Martin Nevertheless.
“ While this potentially augurs future breakthroughs of the predicted dormant black hole population in our Universe, the observations also depart a mystery to be solved— despite a shared background with its exotic neighbor, exactly why is the companion star with this binary system so regular? ”