HD 21749b completes one orbit of its host star, which is almost as bright as our sun, every 36 Earth days. That is fast by Earth standards, but the other two planets include Pi Mensae b with a 6.3-day orbit and LHS 3844b that orbits its star at a blistering pace of once every 11 hours. If this world is confirmed, it will be the first roughly Earth-size planet found by TESS. Why scientists are saying the new planet's surface is relatively cool is because its star is nearly as bright as our very own Sun, the team from the Massachusetts Institute of Technology in Boston said.
The newly described planet whizzes around its star on a stretched-out orbit once every 36 days, says Xu Chelsea Huang, a TESS scientist at the Massachusetts Institute of Technology (MIT) in Cambridge.
"We know a lot about atmospheres of hot planets, but because it's very hard to find small planets that orbit farther from their stars, and are therefore cooler, we haven't been able to learn much about these smaller, cooler planets", she continued. "But here, we were lucky and caught this one and can now study it in more detail".
Its size, three times that of Earth, makes it a sub-Neptune - but it's also 23 times as massive as Earth.
The researchers have also detected evidence of another planet which, if confirmed, could be the first Earth-sized discovery by Tess.
The new world, known as K2-288Bb, could be rocky or could be a gas-rich planet similar to Neptune.
"We think this planet wouldn't be as gaseous as Neptune or Uranus, which are mostly hydrogen and really puffy", Dragomir says.
Experts still aren't sure whether the planet hosts life, but say if plants were transferred there, they would likely survive.
Launched from Cape Canaveral on March 7th 2009, the Kepler telescope has helped in the search for planets outside of the solar system.
Citizen scientists have discovered a potentially habitable exoplanet roughly twice the size of Earth, NASA's Jet Propulsion Laboratory said Monday.
During this time it discovered 2,600 planets around other stars, along with thousands of other candidate celestial bodies which astronomers are working to identify.
She and her colleagues compared the pattern to the first full transit they had originally discovered, and found a near ideal match - an indication that the planet passed again in front of its star, in a 36-day orbit.
TESS will continue to sweep the southern hemisphere until mid-2019, at which point it will turn its cameras to the Northern Hemisphere and start another observation phase. Possible planets can be spotted by studying dips in light when the planet moves before its star. "But we had this one transit, and knew something was there".
They also used data from the Planet Finder Spectrograph, an instrument installed on the Magellan Telescope in Chile, to further validate their findings and constrain the planet's mass and orbit.
Volunteers re-examined the observation data, which is when they came across the new planet. "TESS found as many in its first month".
"This is only the ninth system discovered containing six or more planets", he said.
So the reprocessed, "cleaned-up" light curves were uploaded through the Exoplanet Explorers project on online platform Zooniverse, and the public was invited to "go forth and find us planets", Feinstein said.
In 2017, Feinstein and Makennah Bristow, an undergraduate student at the University of North Carolina Asheville, worked as interns with Joshua Schlieder, an astrophysicist at NASA's Goddard Space Flight Center in Greenbelt, Maryland. More than a dozen universities, research institutes, and observatories worldwide are participants in the mission.