A NASA spacecraft has spotted a new gaseous planet that is 23 times the size of Earth, scientists at the annual American Astronomical Society meeting in Seattle have announced.
The space agency’s planet-hunting TESS ( Transiting Exoplanet Survey Satellite) mission was behind the major finding, and it has also observed three new planets and six supernovae outside our solar system in a three-month period. The MIT-led project’s most recent discovery is the exoplanet named HD 21749b, which has the longest orbital period observed by the spacecraft, at 36 days. The massive planet orbits a nearby, bright star, which is located about 53 light years away in the Reticulum constellation, as reported by The Guardian.
Despite its relative proximity to the star it is orbiting, the planet has quite a cool average surface temperature, which is thought to be about 3,000 Fahrenheit (1,650 Celsius). Scientists believe that it is a gaseous planet rather than a rocky one because of its size, and its atmosphere is denser than Neptune’s or Uranus’.
“It’s the coolest planet we know of around a star this bright. It’s very hard to find small planets that orbit farther from their stars, and are therefore cooler. But here we were lucky, and can now study this one in more detail,” said the discovery team leader, Diana Dragomir, who is a Hubble fellow at MIT’s Kavli Institute for Astrophysics and Space Research.
The TESS mission also found what is being deemed as the “super Earth,” Pi Mensae b, which has an orbital period of six days, as well as LHS 3844b, a rocky planet with a short 11-hour orbital period. Researchers also announced that TESS found evidence of what could be an Earth-sized planet.
“I’m very interested to know whether [it] has an Earth-like density to match its Earth-like radius – this will contribute to our understanding whether Earth-sized planets have diverse compositions or are all roughly similar to Earth,” said report co-author Johanna Teske, who is also a Hubble fellow.
The way that the TESS spacecraft works is that it monitors and analyses specific sections of the sky, covering about 200,000 nearby stars, and then waits for fleeting dips in the light of each star as they probably mean that an orbiting planet passed in front it. While looking for new planets outside the solar system, the MIT-led project also detected several other events, such as images of six supernovae in far-away galaxies, which scientist were later able to see through ground-based telescopes.
“We’re only halfway through TESS’s first year of operations and the data floodgates are just beginning to open,” said George Ricker, the mission’s lead investigator at the Massachusetts Institute of Technology.