Astronomers have proposed a new hypothesis of the birth of the Solar system, explaining its unusual chemical composition.
According to an article published in the Astrophysical journal. our star and its surrounding planets were formed from the nebula around the star wolf – Rayet.
Modern theory suggests that the formation of the Solar system began about 4.6 billion years ago with gravitational collapse a small part giant interstellar molecular clouds.
“Trigger” was the seal of a substance in a gas cloud caused, as it is believed today that the explosion of one or several supernovae.
In favor of this hypothesis is indicated by studies of meteorites – in their structure there is an unusually large number of beryllium-10, calcium-41, and palladium-107 – isotopes which are ejected into space by the supernova.
However, this hypothesis does not fully explain the chemistry of the Solar system. In particular, in ancient meteorites unusually low iron-60, but a lot of aluminium-26 – although at the time of birth of a supernova both compounds are emitted in large quantities.
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Astronomers from the University of Chicago under the leadership under the leadership of Nicholas Dauphas proposed a solution to this puzzle in their opinion, gravitational collapse was caused not by the explosion of a supernova, and outflow of matter star wolf — Rayet.
Today in the milky Way known to very few stars of this type – about 500. This is a very large (usually 20-40 solar masses) and hot objects, many of which are at a late stage of stellar evolution and have either descended from the main sequence.
Over time, stars wolf – Rayet begin to drop your shell: material from the upper layers “escapes” into space in the form of stellar wind at speeds exceeding 1,000 kilometers per second. As soon as the star wolf – Rayet loses its mass, around it is formed the ring nebula, streamlined the stellar wind.
According to the authors of the new work, the Sun could have formed in this nebula.
“The shell of this bubble is a good place for the birth of stars, because the dust and gas are trapped, where it can condense,” says Nicolas Dauphas.
Astronomers think from 1 to 16 percent of sun-like stars could form in such places.
This mechanism explains why in meteorites almost no iron-60. It is known that in the expiry time of the substance from the star wolf-Rayet, releasing large amounts of aluminum-26, but not iron.
There are also young stars wolf – Rayet, which are the transition stage between the beginning of the formation and output on the main sequence.
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