Using data from NASA’s Transiting Exoplanet Survey Satellite (TESS), an international team of astronomers have discovered four exoplanets that are orbiting two stars. The stellar pair is some 130 light-years away from the earth, which is more than eight million times our distance from the sun. Launched in 2018, TESS lies in high-earth orbit doing what it is named for — hunting exoplanets — planets outside our solar system — that are transiting. Transit is when planets block a portion of the light coming from a star. TESS detects such dips in visible starlight and measures the size of the exoplanet and the shape of its orbit. According to scientists, the discovered stars are siblings — formed from the same gas cloud — and moving nearly in the same direction. Astronomers guess they formed around the same time. The stars are about 200 million years old, just 5% of our sun’s age and produce stellar flares stronger and more frequent than our sun.
The stars are 30 light-years apart from each other and named TOI 2076 and TOI 1807. According to scientists, the stars produce about 10 times more ultraviolet radiation than they would if they were as old as our sun.
The planetary system of TOI 2076 has three planets, TOI 2076 b, TOI 2076 c and TOI 2076 d. All three of them are about three to four times bigger than Earth but smaller than Neptune. Their orbits around TOI 2076 finish in 17 days. The other star TOI 1807 has just one planet TOI 1807b, which is about 1.8 times the size of Earth and revolves around its planet really fast, finishing its orbit in just half a day.
Scientists believe that the exoplanets are in the “teenage” or transitional phase of their life cycle. “They’re not newborns, but they’re also not settled down. Learning more about planets in this teen stage will ultimately help us understand older planets in other systems,” said NASA astronomer Christina Hedges, one of the authors of the study in a statement. The findings were published on July 12 in The Astronomical Journal.
Scientists hope that exploring their planetary systems will help scientists understand the evolution of new and young planetary systems.