The First Habitable-zone Earth-sized Planet from TESS. II. Spitzer Confirms TOI-700 d
Abstract
We present Spitzer 4.5 μm observations of the transit of TOI-700 d, a habitable-zone Earth-sized planet in a multiplanet system transiting a nearby M-dwarf star (TIC 150428135, 2MASS J06282325-6534456). TOI-700 d has a radius of ${1.144}_{-0.061}^{+0.062}{R}_{\oplus }$ and orbits within its host star's conservative habitable zone with a period of 37.42 days (Teq ∼ 269 K). TOI-700 also hosts two small inner planets (Rb = ${1.037}_{-0.064}^{+0.065}{R}_{\oplus }$ and Rc = ${2.65}_{-0.15}^{+0.16}{R}_{\oplus }$ ) with periods of 9.98 and 16.05 days, respectively. Our Spitzer observations confirm the Transiting Exoplanet Survey Satellite (TESS) detection of TOI-700 d and remove any remaining doubt that it is a genuine planet. We analyze the Spitzer light curve combined with the 11 sectors of TESS observations and a transit of TOI-700 c from the LCOGT network to determine the full system parameters. Although studying the atmosphere of TOI-700 d is not likely feasible with upcoming facilities, it may be possible to measure the mass of TOI-700 d using state-of-the-art radial velocity (RV) instruments (expected RV semiamplitude of ∼70 cm s-1).
- Publication:
-
The Astronomical Journal
- Pub Date:
- September 2020
- DOI:
- 10.3847/1538-3881/aba4b3
- arXiv:
- arXiv:2001.00954
- Bibcode:
- 2020AJ....160..117R
- Keywords:
-
- Exoplanets;
- Habitable planets;
- Habitable zone;
- Low mass stars;
- Antarctic observatories;
- Exoplanet astronomy;
- Exoplanet detection methods;
- Exoplanet systems;
- 498;
- 695;
- 696;
- 2050;
- 47;
- 486;
- 489;
- 484;
- Astrophysics - Earth and Planetary Astrophysics;
- Astrophysics - Instrumentation and Methods for Astrophysics;
- Astrophysics - Solar and Stellar Astrophysics
- E-Print:
- 14 Pages, 5 Figures, 2 Tables, Accepted to AJ