For decades, astronomers have pondered the mystery of high-speed clouds. It’s about cold, fast-moving hydrogen gas that can only be seen with radio telescopes. However, almost nothing is known with certainty about their distances. Some fly to us. Others are far from us.
It is generally believed that the clouds are located at distances of up to several thousand light years, and that they somehow exploded from the Milky Way. Or it relates to the remnants of dwarf galaxies that will be swallowed up by the Milky Way in the future.
Now the mystery has been solved for one of this high-speed cloud, which is flying towards us at a colossal speed of 120 kilometers per second. At least, according to Joan Schmelz of the Universities Space Research Consortium and her husband and colleague Gerrit Vershor in Astrophysical Journal. she Discover The cloud in the sky coincides with a large globular cavity in the thin gas that lies between the stars of our Milky Way. Such cavities are usually created by supernova explosions – catastrophic explosions that end the lives of massive stars.
high speed cloud
The compact remnants of this supernova may also have been identified. It is about a companion star in the constellation Ursa Major, which can be seen with the naked eye on a dark night. This star was already known to swing back and forth once every 45 years, due to the gravity of a companion orbiting around it.
“The companion was always assumed to be a white dwarf star,” says Virchor, a South African-born radio astronomer. But according to recent research by Belgian astronomer Alain Jurissen, it is likely to be a compact neutron star – the remnant of a supernova explosion. The high-velocity cloud would then be ejected into the dying star’s final life, and then accelerated by the shock wave of the explosion.
Based on the size of the cavity and the speed of the cloud, Schmels and Verschuer concluded that the supernova explosion occurred about 100,000 years ago, at a distance of only 530 light-years – that must have been an amazing sight.
If this scenario holds true, at least this high-speed cloud is close. This can also apply to many other copies. But certainly not for everyone, warns radio astronomer Felix Luckmann of the National Radio Astronomy Observatory in the United States. There are known high-speed clouds that contain few heavy elements and dust particles, and they are known to lie at much greater distances. They are certainly not caused by supernovae.
Filippo Fraternali of the University of Groningen also has reservations about Schmelz and Verschuur’s article. “It could be that, but it’s also conceivable that the high-velocity cloud is very far away and that we see it in the same direction as the cavity in the interstellar gas,” he says. According to Fraternali, you may want to find the spectroscopy “fingerprint” of the cloud in light of a background star not too far away, to confirm the suggested small distance. “I’m not convinced yet.”
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