TOI-942b: A Prograde Neptune in a ∼ 60 Myr Old Multi-transiting System

Wirth, Christopher P. and Zhou, George ORCID: https://orcid.org/0000-0002-4891-3517 and Quinn, Samuel N. and Mann, Andrew W. and Bouma, Luke G. and Latham, David W. and Teske, Johanna K. and Wang, Sharon X. and Shectman, Stephen A. and Butler, R. P. and Crane, Jeffrey D. (2021) TOI-942b: A Prograde Neptune in a ∼ 60 Myr Old Multi-transiting System. The Astrophysical Journal. Letters, 917 (2):L34. pp. 1-7. ISSN 2041-8205


Abstract

Mapping the orbital obliquity distribution of young planets is one avenue toward understanding mechanisms that sculpt the architectures of planetary systems. TOI-942 is a young field star, with an age of ∼60 Myr, hosting a planetary system consisting of two transiting Neptune-sized planets in 4.3 and 10.1 day period orbits. We observed the spectroscopic transits of the inner Neptune TOI-942b to determine its projected orbital obliquity angle. Through two partial transits, we find the planet to be in a prograde orbit, with a projected obliquity angle of |λ| = 1-33+41 deg. In addition, incorporating the light curve and the stellar rotation period, we find the true 3D obliquity to be 2-23+27 deg. We explored various sources of uncertainties specific to the spectroscopic transits of planets around young active stars, and showed that our reported obliquity uncertainty fully encompassed these effects. TOI-942b is one of the youngest planets to have its obliquity characterized, and one of even fewer residing in a multi-planet system. The prograde orbital geometry of TOI-942b is in line with systems of similar ages, none of which have yet been identified to be in strongly misaligned orbits.


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Item Type: Article (Commonwealth Reporting Category C)
Refereed: Yes
Item Status: Live Archive
Faculty/School / Institute/Centre: Current - Institute for Advanced Engineering and Space Sciences - Centre for Astrophysics (1 Aug 2018 -)
Faculty/School / Institute/Centre: Current - Institute for Advanced Engineering and Space Sciences - Centre for Astrophysics (1 Aug 2018 -)
Date Deposited: 02 Mar 2022 06:20
Last Modified: 30 Mar 2022 03:54
Uncontrolled Keywords: Planetary system formation; Planetary science; Exoplanet dynamics; Exoplanet systems; Exoplanets; Mini Neptunes; Astrophysics - Earth and Planetary Astrophysics
Fields of Research (2020): 51 PHYSICAL SCIENCES > 5101 Astronomical sciences > 510109 Stellar astronomy and planetary systems
Socio-Economic Objectives (2020): 28 EXPANDING KNOWLEDGE > 2801 Expanding knowledge > 280120 Expanding knowledge in the physical sciences
Funding Details:
Identification Number or DOI: https://doi.org/10.3847/2041-8213/ac13a9
URI: http://eprints.usq.edu.au/id/eprint/45035

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