by If you were attacked by a fierce vampire star or were in danger of falling into two black black holes, you would probably run too!
It is likely that one of these extreme cases is responsible for sending a low-mass star through the Milky Way at a tremendous speed of one million miles per hour (1.6 million kilometers per hour). That’s about 1,500 times faster than the speed of sound.
The star is named CWISE J124909+362116.0 (J1249+36) and was discovered for the first time by citizen science volunteers with the Backyard Worlds: Planet 9 project, which is investigating the vast amount of data collected by the Wide-field Infrared Survey Explorer ( WISE) of NASA. mission over almost a decade and a half. J1249+36 immediately stood out because of its massive velocity of 1.3 million mph (2.1 million kph) specifically, which is almost three times as fast as the sun orbits around the center of the Milky Way. The speed of this “hypervelocity” star is so great, in fact, that it is likely to escape our entire galaxy.
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To break the secrets of this hypervelocity star, San Diego Professor of Astronomy and Astrophysics Adam Burgasser turned to the WM Keck Observatory in Maunakea, Hawaii, with the aim of observing its infrared spectrum.
This investigation revealed that the star belongs to a class of the oldest stars in the Milky Way: L subdwarfs. These stars are extremely rare and amazing because of their very low masses and relatively cool temperatures.
The team’s spectral data were combined with a new set of atmospheric models created specifically to study L subdwarfs. This revealed the position and velocity of J1249+36 through the Milky Way. “This is where the very interesting source came from,” Burgasser said in a statement. “Its speed and track indicated it was moving fast enough to escape the Milky Way.”
The question is, what sent this subdwarf star on its rapid escape path? Well, that brings us to our two suspects.
Is this star running from a white dwarf vampire?
In the first scenario used to explain the hypervelocity nature of J1249+36, Burgasser and his colleagues hypothesized that the low-mass star was the interstellar companion of a type of “dead” star once known as a white dwarf.
White dwarfs are born when small stars like the sun exhaust the supply of hydrogen in their cores. When that happens, a star’s nuclear fusion ceases. This cuts off the outward flow of energy that supports the star against the inward pressure of its own gravity. Although this ends the lives of lonely, remote stars like the sun, however, white dwarfs in binary systems can return from the grave by cannibalistically feeding on stellar material extracted from a nearby “donor” star.
This material builds up on the white dwarf until the mass of that stellar remnant exceeds the Chandrasekhar limit of about 1.4 times the mass of the Sun, which a star can outgrow the supernova. This results in a type of cosmic explosion known as a “Type Ia supernova” that completely destroys the white dwarf.
“In this type of supernova, the white dwarf is completely destroyed, so its companion is released and flies at whatever orbital speed it was moving at first, plus a bit of a kick from the supernova explosion,” Burgasser explained. “Our calculations show that this scenario works. However, the white dwarf no longer exists, and the remains of the explosion, which probably happened several million years ago, have already dispersed, so there is no proof We are certain that this is his origin.”
Could a few black holes be involved?
In the second scenario considered by the team, this hypervelocity star begins its life in a globular cluster, a compact and compact conglomerate of stars bound together by gravity. These globular clusters can contain anywhere from thousands to millions of stars.
The stars are concentrated toward the center of globular clusters, where scientists theorize that black holes of varying masses also lie. These black holes can coalesce and form binaries capable of launching any stars that pass too close to them from their home systems.
“When a star becomes a black hole binary, the complex dynamics of the interaction between these three bodies can throw that star out of the globular cluster,” said Kyle Kremer, a new Assistant Professor in UC San Diego’s Department of Astronomy and Astrophysics.
Simulations generated by Kremer showed that these types of interactions can, on rare occasions, kick low-mass dwarfs out of a globular cluster and put them on trajectories similar to that observed with J1249+36.
The team also tracked this hypervelocity star back to a very crowded region of space, which could be the location of a currently undiscovered globular cluster — or, maybe. more than any.
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The team will now look at the elemental composition of J1249+36 in an attempt to determine which of these extinction scenarios is correct. Composition could be a possible indication of origin because when white dwarfs “go nova,” they pollute the stars they host. In addition, stars born in globular clusters have a specific chemical composition.
Whatever the origin of this star, its discovery gives scientists a unique opportunity to investigate hypervelocity constellations as a whole. And it’s all very cool.
Burgasser presented the team’s findings at a press conference Monday (June 10) during the 244th national meeting of the American Astronomical Society (AAS) in Madison, Wisconsin.
