Nasa's Transiting Exoplanet Survey Satellite has found a new Earth-sized exoplanet called HD 21749c. It's the first discovery done by TESS.
It is said to be a prime target for comparative studies of planetary composition and architecture in multi-planet systems and rotates every eight days in the orbit of its host star.
The satellite also found its planetary sibling named HD 21749b. It is categorized as a sub-Neptune based on its mass that is equivalent of about 23 times of Earth and its radius that is about 2.7 times that of Earth.
The results of the study were published in the scientific journal Astrophysical Journal Letters.
"It's so exciting that TESS, which launched just about a year ago, is already a game-changer in the planet-hunting business," said Johanna Teske, a Hubble postdoctoral fellow at the Carnegie Institution for Science.
"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."
MIT astronomers R. Paul Butler, Stephen Shectman, Jeff Crane, and Sharon Wang, collaborated on this recent study.
Radial Velocity Method
It is said that the Planet Finder Spectrograph on the Magellan II telescope is a major component in this discovery. It helped to confirm the planetary nature of the TESS signal and measured the mass of the newly discovered sub-Neptune using a technique called radial velocity method.
This is an indirect method for finding extrasolar planets that are measured in terms of the change in the distance from the sun to the star and is currently the only way for astronomers to measure the masses of the planet.
NASA expects TESS to discover thousands of exoplanets of all sizes around a variety of star types that will help in building an understanding of how many and what kinds of planetary systems nature has provided and to see if there's any sign of extraterrestrial life or show signs of possible life that we know how to interpret.