TESS finds its first Earth-sized planet:

[beecee]

https://phys.org/news/2019-04-tess-earth-sized-planet.html

A nearby system hosts the first Earth-sized planet discovered by NASA's Transiting Exoplanets Survey Satellite, as well as a warm sub-Neptune-sized world, according to a new paper from a team of astronomers that includes Carnegie's Johanna Teske, Paul Butler, Steve Shectman, Jeff Crane, and Sharon Wang.

Their work is published in the 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 Teske, who is 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."

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.

more at link.....

 

the paper:

https://iopscience.iop.org/article/10.3847/2041-8213/ab12ed/meta

TESS Delivers Its First Earth-sized Planet and a Warm Sub-Neptune*:

Abstract:

The future of exoplanet science is bright, as Transiting Exoplanet Survey Satellite (TESS) once again demonstrates with the discovery of its longest-period confirmed planet to date. We hereby present HD 21749b (TOI 186.01), a sub-Neptune in a 36 day orbit around a bright (V = 8.1) nearby (16 pc) K4.5 dwarf. TESS measures HD 21749b to be  R ⊕, and combined archival and follow-up precision radial velocity data put the mass of the planet at  M ⊕. HD 21749b contributes to the TESS Level 1 Science Requirement of providing 50 transiting planets smaller than 4 R ⊕ with measured masses. Furthermore, we report the discovery of HD 21749c (TOI 186.02), the first Earth-sized () planet from TESS. The HD 21749 system is a prime target for comparative studies of planetary composition and architecture in multi-planet systems.