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 {2.61}-0.16+0.17 R ⊕, and combined archival and follow-up precision radial velocity data put the mass of the planet at {22.7}-1.9+2.2 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 ({R}p={0.892}-0.058+0.064{R}\oplus ) planet from TESS. The HD 21749 system is a prime target for comparative studies of planetary composition and architecture in multi-planet systems.
This Letter includes data gathered with the 6.5 m Magellan Telescopes located at Las Campanas Observatory, Chile.- Publication:
-
The Astrophysical Journal
- Pub Date:
- April 2019
- DOI:
- 10.3847/2041-8213/ab12ed
- arXiv:
- arXiv:1901.00051
- Bibcode:
- 2019ApJ...875L...7D
- Keywords:
-
- planetary systems;
- planets and satellites: detection;
- stars: individual: HD 21749;
- TIC 279741379;
- Astrophysics - Earth and Planetary Astrophysics;
- Astrophysics - Solar and Stellar Astrophysics
- E-Print:
- Published in ApJ Letters