A transiting multiplanet system in the 61 Myr old association Theia 116

ABSTRACT Observing and characterizing young planetary systems can aid in unveiling the evolutionary mechanisms that sculpt the mature exoplanet population. As an all-sky survey, NASA’s Transiting Exoplanet Survey Satellite (TESS) has expanded the known young planet population as it has observed young comoving stellar populations. This work presents the discovery of a multiplanet system orbiting the 61$\pm 6$ Myr old G4V star TIC 434398831 ($M_\star = 0.99\, \mathrm{M_\odot }$, $R_\star = 0.91\, \mathrm{R_\odot }$, $T_\mathrm{eff} = 5638\,$K, $T\mathrm{mag} = 11.31$) located in the Theia 116 comoving population. We estimate the population’s age based on rotation periods measured from the TESS light curves, isochrone fitting, and measurements of lithium equivalent widths in the spectra of Theia 116 members. The TESS FFI light curves reveal a mini-Neptune ($R_b = 3.51\, \mathrm{R_{\oplus }}$, $P_b = 3.69$ d) and super-Neptune ($R_c = 5.63\, \mathrm{R_{\oplus }}$, $P_c = 6.21$ d) with an orbital period ratio slightly larger than 5:3. Follow-up observations from CHEOPS and ground-based telescopes confirm the transits of TIC 434398831 b and c, and constrain their transit times. We explore the potential mass-loss histories of the two planets in order to probe possible initial conditions of the planets immediately after formation.

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Publication Details

Journal
Monthly Notices of the Royal Astronomical Society
Published
2025-05-09
DOI
https://doi.org/10.1093/mnras/staf726
Citations
3
Primary Topic
Astro and Planetary Science
Type
article
Field-Weighted Citation Impact
3.46

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article

A transiting multiplanet system in the 61 Myr old association Theia 116

Samuel N. Quinn, Ismael Mireles, Andrew W. Mann, Ramotholo Sefako et al.
3 citations
Monthly Notices of the Royal Astronomical Society
Astro and Planetary Science
3.46
article

A transiting multiplanet system in the 61 Myr old association Theia 116

Samuel N. Quinn, Ismael Mireles, Andrew W. Mann, Ramotholo Sefako, Stephanie T. Douglas, Akihiko Fukui, David W. Latham, Madyson G. Barber, Howard M. Relles, W. Fong, Karen A. Collins, Steve B. Howell, Sara Seager, Richard P. Schwarz, Colin Littlefield, Khalid Barkaoui, G. Ricker, Chelsea X. Huang, Kevin I. Collins, Guillermo Torres, Sydney Vach, George Zhou, Luke G. Bouma, James G. Rogers, Kim K. McLeod, Sarah J. Deveny, Allyson Bieryla, Tyler R. Fairnington, Avi Shporer, Norio Narita, J. Krüger, Joshua N. Winn, Gregor Srdoč, Alayna Schneider
article en
3 citations

Abstract

ABSTRACT Observing and characterizing young planetary systems can aid in unveiling the evolutionary mechanisms that sculpt the mature exoplanet population. As an all-sky survey, NASA’s Transiting Exoplanet Survey Satellite (TESS) has expanded the known young planet population as it has observed young comoving stellar populations. This work presents the discovery of a multiplanet system orbiting the 61$\pm 6$ Myr old G4V star TIC 434398831 ($M_\star = 0.99\, \mathrm{M_\odot }$, $R_\star = 0.91\, \mathrm{R_\odot }$, $T_\mathrm{eff} = 5638\,$K, $T\mathrm{mag} = 11.31$) located in the Theia 116 comoving population. We estimate the population’s age based on rotation periods measured from the TESS light curves, isochrone fitting, and measurements of lithium equivalent widths in the spectra of Theia 116 members. The TESS FFI light curves reveal a mini-Neptune ($R_b = 3.51\, \mathrm{R_{\oplus }}$, $P_b = 3.69$ d) and super-Neptune ($R_c = 5.63\, \mathrm{R_{\oplus }}$, $P_c = 6.21$ d) with an orbital period ratio slightly larger than 5:3. Follow-up observations from CHEOPS and ground-based telescopes confirm the transits of TIC 434398831 b and c, and constrain their transit times. We explore the potential mass-loss histories of the two planets in order to probe possible initial conditions of the planets immediately after formation.

Monthly Notices of the Royal Astronomical SocietyVol. 540(1)
University of North Carolina at Chapel Hill (US), California Institute of Technology (US), Ames Research Center (US), Planetary Science Institute (US), University of Liège (BE), University of California, Los Angeles (US), George Mason University (US), University of New Mexico (US), Lafayette College (US), University of Southern Queensland (AU), Wellesley College (US), Princeton University (US), Pulkovo Observatory (RU), Bay Area Environmental Research Institute (US), Astrobiology Center (JP), South African Radio Astronomy Observatory (ZA), Center for Astrophysics Harvard & Smithsonian (US), Instituto de Astrofísica de Canarias (ES), Tokyo Metropolitan Komaba High School (JP), Astronomical Observatory (RS), American Institute of Aeronautics and Astronautics (US), Massachusetts Institute of Technology (US), The University of Tokyo (JP)
National Science Foundation, National Aeronautics and Space Administration, Fund for Astrophysical Research, California Institute of Technology, Fonds De La Recherche Scientifique - FNRS, Korea Astronomy and Space Science Institute, Ministério da Ciência, Tecnologia, Inovações e Comunicações, Agencia Nacional de Investigación y Desarrollo, Ames Research Center, Science Mission Directorate, Japan Society for the Promotion of Science, Precursory Research for Embryonic Science and Technology
Openalex Percentile: Top 8%
Astro and Planetary Science
3.46
DOIOpen Access PDFOpenAlex
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