“If you’re standing on the surface of that planet, there are three suns in the sky, but two of them are pretty far away and small-looking. They’re like two red, ominous eyes in the sky.”
That’s the made-for-a-sci-fi-novel description of the otherwise boringly-named planet LTT 1445Ab discovered recently just 22.5 light-years away from Earth. It’s hot – three suns will do that to a planet – but it has an atmosphere, so it’s getting some interest from astronomers. How about a better name first? Ghidorah? Triple Sol? My Three Suns? Ta-three-ine?
“It is the second nearest transiting exoplanet system found to date, and the closest one known for which the primary is an M dwarf.”
Artist’s rendition of the view from a hypothetical moon in orbit around the first known planet to reside in a tight-knit triple-star system. (Credit: JPL)
According to their new report, “Three Red Suns in the Sky: A Transiting, Terrestrial Planet in a Triple M Dwarf System at 6.9 Parsecs,” submitted this week to The Astronomical Journal, astronomers led by Jennifer Winters of the Harvard-Smithsonian Center for Astrophysics used data from the Transiting Exoplanet Survey Satellite (TESS) space telescope launched last year to search for exoplanets using the transit method to locate changes in the light of a star that indicates a planet passing in front of it. While LTT 1445Ab is in a three-star system, it only orbits one of them, and that orbit is a scorchingly-fast once every 5.36 Earth days – extremely speedy for a planet just slightly larger than Earth (1.35 times the size) but much denser (8 times the mass) and hotter (surface temperatures 311 °F (155 °C or 428 Kelvin).
“The presence of a transiting planet in this system raises the possibility that the entire system is co-planar, which implies that the system may have formed from the early fragmentation of an individual protostellar core.”
Spider’s view from LTT 1445Ab?
While the atmosphered planet is interesting, the three suns are more intriguing, and LTT 1445Ab could shed some light (by ironically blocking it) on how these three-sun systems formed. Yes, there’s more – ScienceAlert points out that planet HD 131399Ab, discovered in 2016, orbits three suns 340 light-years away in a very slow 550-year orbit, making it far less suitable for study. The study surmises that the three suns of LTT 1445Ab may be the fragments of a single star that broke apart early in the history of the universe. The astronomers are hoping that the new James Webb Space Telescope, scheduled to be launched in 2021, will help answer the question.
Three Suns and a Rock. Great name for a band or a sci-fi movie. Any other ideas?
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