In:
The Astronomical Journal, American Astronomical Society, Vol. 163, No. 4 ( 2022-04-01), p. 156-
Abstract:
Mature super-Earths and sub-Neptunes are predicted to be ≃ Jovian radius when younger than 10 Myr. Thus, we expect to find 5–15 R ⊕ planets around young stars even if their older counterparts harbor none. We report the discovery and validation of TOI 1227b, a 0.85 ± 0.05 R J (9.5 R ⊕ ) planet transiting a very-low-mass star (0.170 ± 0.015 M ⊙ ) every 27.4 days. TOI 1227's kinematics and strong lithium absorption confirm that it is a member of a previously discovered subgroup in the Lower Centaurus Crux OB association, which we designate the Musca group. We derive an age of 11 ± 2 Myr for Musca, based on lithium, rotation, and the color–magnitude diagram of Musca members. The TESS data and ground-based follow-up show a deep (2.5%) transit. We use multiwavelength transit observations and radial velocities from the IGRINS spectrograph to validate the signal as planetary in nature, and we obtain an upper limit on the planet mass of ≃0.5 M J . Because such large planets are exceptionally rare around mature low-mass stars, we suggest that TOI 1227b is still contracting and will eventually turn into one of the more common 〈 5 R ⊕ planets.
Type of Medium:
Online Resource
ISSN:
0004-6256
,
1538-3881
DOI:
10.3847/1538-3881/ac511d
Language:
Unknown
Publisher:
American Astronomical Society
Publication Date:
2022
detail.hit.zdb_id:
2207625-6
detail.hit.zdb_id:
2003104-X
SSG:
16,12