Astronomers at the Harvard -Smithsonian Center for Astrophysics have discovered a Jupiter-like gas giant planet in a triple-star system. The KELT system where the gas giant is located is just 680 light years away from Earth. Scientists have known the KELT system since 1973. But they believed that the binary star pair was a single star, and it was a two-star system.
Two stars in KELT system orbit each other
The latest study reveals that the binary system was actually a pair of starts orbiting each other, and they were part of the triple-star system. The KELT system is only the fourth triple-star system to be found and it is closest to our planet. Researchers said the primary star is much brighter than the other two stars, making it easier to study both the planet and the star.
The gas giant known as KELT-4Ab takes about three days to orbit its sun KELT-A. The other two stars in the system, KELT-B and KELT-C complete one orbit around each other in 30 years. Researchers estimate that these two stars take roughly 4,000 years to orbit KELT-A. Findings of the study were published in the Astronomical Journal.
Why KELT-4Ab is called ‘hot Jupiter’
Due to the planet’s close proximity with KELT-A, the sun appears from KELT-4Ab 40 times bigger than our sun does from Earth. The other two stars appear only as big as a bright full moon from our planet. The gas giant is so close to its sun that its atmosphere is inflated by the heat, prompting scientists to classify it as a “hot Jupiter.” The discovery gives astronomers an opportunity to closely study such systems in space.
Harvard-Smithsonian scientists used a robotic telescope called the Kilodegree Extremely Little Telescope (KELT), one of which is located in Arizona and another in South Africa. Researchers plan to further study the system to figure out how gas giant planets manage to withstand being so close to their host star. They will also re-evaluate planet formation theories because three-star systems produce competing gravitational pulls that might affect planet formation.