The majority of stars in our galaxy come in pairs, triplets or even quadruplets, but our sun appears to be a loner. This fact poses an interesting question: if our star is alone, and yet contains a rich multiplanetary system, how do planetary systems evolve in multi-star systems?
In a new study published in the journal Nature this week, Alyssa Goodman, professor of astronomy at the Harvard-Smithsonian Center for Astrophysics (CfA), reports on the discovery of four embryonic stars slowly forming 825 light-years from Earth. Previously known to contain one protostar, the molecular cloud located in the constellation Perseus apparently contains more stellar siblings.
One of the biggest puzzles in understanding the evolution of multi-star systems is how they formed; did they spawn from the same stellar nursery as true fraternal twins would or did the stars come from different locations only to be gravitationally captured later in their lives? According to theoretical models both ideas are viable.
By studying the radio emissions from the molecular cloud, Goodman’s team discovered “several filamentary gas structures in which they detected three other concentrations,” writes a Smithsonian Astrophysical Observatory news release.
The researchers believe that these gas concentrations, which are two-to-three times more massive than the known protostar, are collapsing under mutual gravity. In other words, stellar quadruplets are coalescing and three of these newly-detected star embryos will likely undergo nuclear fusion in their cores, becoming baby stars, in roughly 40,000 years time. In cosmic timescales, this particular stellar womb is teetering on the edge of giving birth.
Most interesting is the scale of the region. The system measures only 10,000 astronomical units (AU) across — where 1 AU is the average distance between the Earth and sun. For scale, all four stellar embryos would fit easily within the boundaries of our solar system, where the outermost boundary is the Oort Cloud, a hypothetical region containing billions of cometary nuclei surrounding our sun. The inner Oort Cloud’s outermost boundary is 20,000 AU from the sun.
Their close proximity means that all four stars are gravitationally interacting and velocity measurements confirms this possibility.
Read more at Discovery News
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