Astronomers have reported that a nearby star system is home to an Earth-sized planet which was discovered by the Transiting Exoplanets Survey Satellite, NASA’s brand-new exoplanet hunter.
The study detailing the discovery has been published in the Astrophysical Journal Letters by a team of astronomers led by the Carnegie Institution for Science.
In the study, they report the discovery of a warm Earth-sized sub-Neptune.
With an orbit that takes approximately 36 days to complete, the newly-found exoplanet dubbed HD 21749b has the longest period of all TESS discoveries published so far.
Due to the technique used by TESS, it is anticipated that most of the planets that the mission will encounter will have orbital periods of less than 10 days, so HD 21749b is unusual in this sense.
In fact, this also made detection of the planet in the TESS data an additional challenge.
“There was quite some detective work involved, and the right people were there at the right time,” said lead author Diana Dragomir of MIT’s Kavli Institute for Astrophysics and Space Research.
“But we were lucky, and we caught the signals, and they were really clear.”
“It’s so exciting that TESS, which launched just about a year ago, is already a game-changer in the planet-hunting business,” explained Johanna Teske, who is the second author on the paper.
“The spacecraft surveys the sky and we collaborate with the TESS follow-up community to flag potentially interesting targets for additional observations using ground-based telescopes and instruments.”
As noted by scientists; “One such tool, the Planet Finder Spectrograph on the Magellan II telescope at Carnegie’s Las Campanas Observatory in Chile, was a crucial component of this effort. It helped confirm the planetary nature of the TESS signal, and to measure the mass of the newly discovered sub-Neptune.”
The exoplanet orbits a star that has around 80 percent of the mass of our sun. The Sub-Neptune wold is located around 53 light years from us and is around 23 times Earth’s mass and a radius of about 2.7 times Earth’s.
As noted by astronomers, its density reveals that the exoplanet has a substantial atmosphere engulfing it, but it not a rocky planet.
Thanks to TESS, astronomers will be able to measure the masses, atmospheric compositions, and other properties of many smaller exoplanets for the first time.