Imagine what would life be like on a planet in a solar system with three stars, with the combined binary 12 times larger than our Sun and the third star a colossal 16 times the mass of the Sun. “As far as we know, it is the first of its kind ever detected”, astrophysicist Alejandro Vigna-Gomez at the Niels Bohr Institute says about the discovery of a massive, triple star system, TIC 470710327, with two stars orbiting one another in a binary and the third orbiting the binary, according to a study published in the Monthly Notices of the Royal Astronomical Society.
“We know of many tertiary star systems (three star systems), but they are typically significantly less massive. The massive stars in this triple are very close together – it is a compact system.”
The combined binary is 12 times larger than the Sun; the third star is a colossal 16 times the mass of the Sun. The largest known star in the Universe, R136a1, a Wolf–Rayet star, has an estimated mass of 315 solar masses.
This odd star system was recently identified by NASA’s Transiting Exoplanet Survey Satellite. Any evidence that the third star is a highly magnetized (∼1–10 kG), slowly rotating blue main-sequence star, would hint at a quadruple origin. The origin of TIC 470710327 say the discovery team is crucial in our understanding of multiple massive star formation and evolution. The scientists behind the discovery believe this system likely formed as two sets of binaries orbiting each other.
In 2021 in a distant star system called GW Ori, 1,300 light-years away from Earth, researchers and astronomers using the powerful Atacama Large Millimeter/submillimeter Array (ALMA) telescope in Chile, may have discovered the first known planet to orbit not one, or two, but three stars, according to a study published in the Monthly Notices of the Royal Astronomical Society.
The Last Word — Dr. Alejandro Vigna-Gomez
In an email to Alejandro Vigna-Gomez we asked: is there any evidence that the third star is a highly magnetized, slowly rotating blue main-sequence star that would hint at a quadruple origin? He replied:
“There is currently no evidence nor reports on the magnetic field of any of the component stars of TIC 470710327. This is not surprising given that it is a recent discovery. Moreover, these observations are non-trivial to make, particularly for such a compact system. However, we have access to some archival data as well as some new, independent observations. We hope to investigate this further in the next months.”
We also asked, can you expand on the observation that the origin of TIC 470710327 is crucial in our understanding of multiple massive star formation and evolution. He replied:
“Stellar mergers are known to occur, but their frequency and the role they play is still uncertain. Understanding the formation of TIC 470710327 can provide a unique anchor for some of the most extreme stellar systems: compact, massive multiple-star systems (compact imply orbital period of ~1 day, while massive means at least a few time more massive than the Sun).
“In the context of stellar formation, it is quite different to form a quadruple than a triple, particularly when the quadruple has four stars with similar masses (and therefore evolutionary timescales) in contrast to a triple with a more extreme configuration. It can also further inform us about the multiplicity fraction of stellar binaries; that is how common is it for a massive star to have one or more stellar companions. This formation scenario also suggests a deficiency of highly inclined triples, something that is consistent with low-mass triples but still uncertain for a large population of massive stellar triples.
“Finally, TIC 470710327 is so extraordinary and unique that any details we can understand from this system can result in a novel interpretation and understanding of the theory of massive stars.”
Image credit: Shutterstock License
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