NASA has discovered an Earth-sized planet orbiting a distant star – and one that may be suitable for human habitation. The star known as TOI 700 e is the fourth discovered in the TOI 700 system located 100 light years away. The research team presented the findings at the American Astronomical Society meeting in Seattle .
TOI 700 is a dwarf star at the center of the system, home to the recently discovered TOI 700 b, c and d planets. However, only two of the four planets, d and e, have conditions that could be suitable for life. “This is one of the few systems with multiple, small, habitable-zone planets that we know of,” said Emily Gilbert, of NASA’s Jet Propulsion Laboratory in Southern California who led the study.
The scientists used data from NASA’s TESS space telescope to identify the new planet, which is about 95% the size of Earth and likely rocky. Planet e takes 28 days to orbit its star, while d has a 37-day orbit. The innermost planet, b, is about 90% the size of Earth and is in a 10-day orbit around the star.TOI 700 c is 2.5 times larger than Earth and orbits the star every 16 days.
The researchers believe the planets are likely tidally locked, meaning they rotate only once in each orbit, so one side always faces the star — similar to how Earth only sees one side of the moon. Finding other systems with Earth-sized planets could actually help scientists learn more about our solar system.
Designed to detect distant planets and stars, TESS has four cameras that can see 85% of the sky while searching for exoplanets orbiting stars less than 300 light-years away. It tracks large parts of the sky for about 27 days at a time and allows it to track any changes in brightness caused by a previously unseen planet.
“TESS has just completed its second year of observations of the northern sky,” said Alison Youngblood, a research astrophysicist and deputy TESS project scientist at NASA’s Goddard Space Flight Center. “We look forward to the rest of the exciting discoveries that lie ahead.”
Since TESS’s launch, it has discovered more than 260 “confirmed” planets, along with 4,000 “candidate” stars that remain to be verified. About 1,700 potential stars were disqualified. More than 5,000 exoplanets have been discovered and “confirmed” by NASA out of the billions that exist in our Milky Way galaxy alone. In 2022, over 300 exoplanets have been identified.