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Title: TESS Hunt for Young and Maturing Exoplanets (THYME). XI. An Earth-sized Planet Orbiting a Nearby, Solar-like Host in the 400 Myr Ursa Major Moving Group
Abstract

Young terrestrial worlds are critical test beds to constrain prevailing theories of planetary formation and evolution. We present the discovery of HD 63433 d—a nearby (22 pc), Earth-sized planet transiting a young Sun-like star (TOI-1726, HD 63433). HD 63433 d is the third planet detected in this multiplanet system. The kinematic, rotational, and abundance properties of the host star indicate that it belongs to the young (414 ± 23 Myr) Ursa Major moving group, whose membership we update using new data from the third data release of the Gaia mission and TESS. Our transit analysis of the TESS light curves indicates that HD 63433 d has a radius of 1.1Rand closely orbits its host star with a period of 4.2 days. To date, HD 63433 d is the smallest confirmed exoplanet with an age less than 500 Myr, and the nearest young Earth-sized planet. Furthermore, the apparent brightness of the stellar host (V≃ 6.9 mag) makes this transiting multiplanet system favorable to further investigations, including spectroscopic follow-up to probe the atmospheric loss in a young Earth-sized world.

 
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Award ID(s):
2143763
PAR ID:
10502784
Author(s) / Creator(s):
; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; more » ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; « less
Publisher / Repository:
Journals of the AAS
Date Published:
Journal Name:
The Astronomical Journal
Volume:
167
Issue:
2
ISSN:
0004-6256
Page Range / eLocation ID:
54
Format(s):
Medium: X
Sponsoring Org:
National Science Foundation
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