The planet-hunting TESS spacecraft has found its first Earth-size planet orbiting a star located about 53 light years away. The star, HD 21749a, also hosts at least one other world, a warm “sub-Neptune” planet with a mass about 23 times that of Earth and a radius about 2.7 times larger.
“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, second author of a paper describing the discoveries in The Astrophysical Journal Letters.
“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,” she added.
That includes the Planet Finder Spectrograph – PFS – on the Magellan II telescope at Carnegie’s Las Campanas Observatory in Chile, which played a crucial role in the new discoveries.
The Transiting Exoplanets Survey Satellite, or TESS, was launched 18 April 2018. It detects exoplanets by measuring the slight dimming of a star’s light when a planet moves across the disc as viewed from Earth. The PFS was used to compute the mass of the sub-Neptune world by precisely measuring the very slight wobble in the ...