In May of 2020 a team of astronomers from the European southern observatory and other
institutes discovered a black hole lying just a thousand light years from earth or so they thought
this supposed black hole was thought to be the closest black hole found to our solar system
and was part of a triple system but now another team of scientists has
claimed that this black hole never existed welcome to Factnomenal and
let's find out why the closest black hole to earth never really existed in the first place
using the 2.2 meter telescope a team of scientists at the European Southern
Observatory's la cia observatory in Chile found evidence for a black hole
just 1 000 light years from earth by tracking its two companion stars in the hr-6819 triple system
at the time this discovery was hoped to just be the tip of the iceberg as many more similar
black holes could be found in the future following this success and that's the cutting edge of what's
happening right now before this discovery the closest known black hole was a0620-00
in the constellation of Monoceros at a distance of 3 000 light years the researchers were totally
surprised when they realized that this is the first stellar system with a black
hole that can be seen with the unaided eye located in the constellation of telescopium
the system is so close to us that its stars can be viewed from the southern hemisphere on a
dark clear night without binoculars or a telescope the team originally observed the system called
hr 6819 as part of a study of double star or binary systems however as they analyzed their
observations they were stunned when they revealed a third previously undiscovered body in h.r 6819
that they then assumed was a black hole but they had solid reasoning behind such a conclusion an
invisible object with a mass at least four times that of the sun could only be a black hole until
now astronomers have spotted only a couple of dozen black holes in our galaxy to date
nearly all of which strongly interact with their environment and make their presence
known by releasing powerful x-rays in this interaction but scientists estimate that many
more stars collapsed into black holes as they ended their lives over the milky way's lifetime
there were soon estimates about another similar triple system lb-1 to have a black hole in it too
lb-1 is located a bit further than h.r 6819 but still pretty close in astronomical terms
so astronomers were hyped about finding more such systems in our galactic cul-de-sac however this
was 2020 and we all know that year gave us nothing good and such was the case with this news too
in other research a team of scientists in belgium disputed the findings of the black
hole in system h.r 6819 and it turned out these critics were correct and there was no black hole
in the concerned system ever the belgian team began investigating the exceptional finding
in 2020 themselves and their conclusion was a little different this counter study posited that
the system could also contain just two stars if one was tripping away and absorbing much of the
mass of the other a phenomenon that's sometimes referred to as stellar vampirism vampire stars are
just like vampires in our myths and on silver screens they appear in the ancient
neighborhoods of the galaxy and yet appear younger hotter and dashing like a newer star
a prominent example of these vampiric stars are blue stragglers which have baffled astronomers for
years since their discovery in 1953 for lagging or straggling behind their ancient neighbors
when it comes to aging as they appear hotter younger and bluer for decades scientists debated
about the source of their elongated youth and there were many possibilities considered it was
hypothesized that they must have come across extra hydrogen fuel that helped them burn hotter but it
was uncertain whether they did so by merging with other stars colliding with victims or stealing
hydrogen from companions in 2011 researchers found evidence that indeed many stars like
blue stragglers are cannibalistic in nature and are fond of eating their binary system partners
astronomers used the wynn observatory in tucson arizona to analyze 21 blue stragglers in ngc 188
ngc 188 is a 7 billion year old cluster of about 3 000 stars in the constellation cepheus located
in the sky near polaris the north star they combined these observations with computer models
simulating the leading theories of blue straggler formation the scientists ruled out star mergers
and interstellar collisions as origins for most of these blue stragglers instead their data suggests
they fed off partner stars solving the mystery of where these blue stragglers come from the
fact that the majority of blue stragglers in the study are in binaries or in other words
they have a companion star further solidifies the vampiric theory of their anti-aging shenanigans
the belgian team joined hands to look deeper into this matter by investigating h.r 6819 more closely
and determining which explanation was more likely the scenarios these researchers were
looking for were rather clear very different and easily distinguishable with the right instrument
but what would qualify to be that right instrument the european southern
observatory's very large telescope and very large telescope interferometer that's what
the original research team also used eso's facilities but they had worked with a relatively
small telescope the belgian team was taking no chances to get accurate evidence the very large
telescope and very large telescope interferometer are two powerful instruments based in chile that
could produce far more detailed images of hr6819 than the tools used in the original team's first
study with the more powerful observations the situation in hr6819 was clear there are only
two stars in a tight orbit and no black hole to speak of but the absence of a black hole is
nothing to mourn according to the belgian team the best interpretation so far is that we caught this
binary system in a moment shortly after one of the stars had sucked the atmosphere off its companion
star which confirms an acute case of stellar vampirism this finding from h.r 6819 is really
exciting as catching such a post-interaction phase is extremely difficult as it's so short
such a case now presents a perfect candidate to study how this vampirism affects the evolution of
massive stars and in turn the formation of their associated phenomena including gravitational waves
and violent supernova explosions the newly formed luvang iso joint team now plans to monitor hr6819
more closely using the vlti's gravity instrument the researchers will conduct a joint study of
the system over time to better understand its evolution constrain its properties and use that
knowledge to learn more about other binary systems as for the search for black holes there's still
hope of finding more stellar-sized black holes as we stumbled upon another one last year in 2021
the black hole discovered in 2021 by a team of astronomers at ohio state university was
dubbed unicorn in part because it's unique and in part because it was found in the constellation
monoceros named by ancient astronomers after the greek word for the unicorn
unicorn may not be as near as the now debunked black hole in hr6819 but it's not that far either
positioned 1500 light years from the earth moreover what makes unicorn unique is its size the
unicorn is truly one of the smallest black holes possible with a stellar mass of only three suns
most known black holes have been found by searching for the x-rays emitted when the
invisible object pulls material off an orbiting companion star as that material
heats up in a dense ring around the black hole known as an accretion disk it emits radiation
that can be detected with x-ray telescopes the unicorn however was found by a different method
researchers used data from several observatories to measure periodic changes in the brightness and
spectrum of light coming from a red giant star known as v723 mon these types of observations
have been used for several decades to search for exoplanets which can be extremely difficult
to spot directly data show that an invisible object is tugging at the red giant star and
the pole was distorting the star into a raindrop shape the team deduced two possibilities from the
combined mass of both objects provided by the data possibility one suggested that if the star
alone is heftier than the team's estimate then its unseen companion has to be a neutron star however
the team's study is leaning towards possibility number two the companion being a small black hole
smallest will probably ever find although the unicorn is changing the shape of the red giant it
isn't pulling material off it that means there's no accretion desk and therefore no x-rays which
is why it went unnoticed until now this lack of x-ray emissions from such quiet black holes
may account for why so few small ones have been found so far if the unicorn is indeed a black hole
studying it will most likely reveal the means to find the means to spot tens to hundreds of
millions of black holes that are possibly out there in the milky way it's just a matter of
time tell us in the comments what impact do you think small black holes will have
on the course of humanity and our science and as always thank you for watching Factnomenal