TOI-1468: A system of two transiting planets, a super-Earth and a mini-Neptune, on opposite sides of the radius valley
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aa44056-22.pdf
Description
Published version
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18 MB
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Adobe PDF
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Author(s)
Seager, Sara
Date Issued
2022
Journal
Astronomy and Astrophysics
Publisher
EDP Sciences
Citation
Seager, Sara. 2022. "TOI-1468: A system of two transiting planets, a super-Earth and a mini-Neptune, on opposite sides of the radius valley." Astronomy and Astrophysics, 666.
Version
Final published version
Abstract
We report the discovery and characterization of two small transiting planets orbiting the bright M3.0 V star TOI-1468 (LSPM
J0106+1913), whose transit signals were detected in the photometric time series in three sectors of the TESS mission. We confirm
the planetary nature of both of them using precise radial velocity measurements from the CARMENES and MAROON-X spectrographs, and supplement them with ground-based transit photometry. A joint analysis of all these data reveals that the shorter-period
planet, TOI-1468 b (Pb = 1.88 d), has a planetary mass of Mb = 3.21 ± 0.24 M⊕ and a radius of Rb = 1.280+0.038
−0.039 R⊕, resulting in a
density of ρb = 8.39+1.05
−0.92 g cm−3
, which is consistent with a mostly rocky composition. For the outer planet, TOI-1468 c (Pc = 15.53 d),
we derive a mass of Mc = 6.64+0.67
−0.68 M⊕, a radius of Rc = 2.06 ± 0.04 R⊕, and a bulk density of ρc = 2.00+0.21
−0.19 g cm−3
, which corresponds
to a rocky core composition with a H/He gas envelope. These planets are located on opposite sides of the radius valley, making our
system an interesting discovery as there are only a handful of other systems with the same properties. This discovery can further help
determine a more precise location of the radius valley for small planets around M dwarfs and, therefore, shed more light on planet
formation and evolution scenarios.
MIT Department
Massachusetts Institute of Technology. Department of Earth, Atmospheric, and Planetary Sciences
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Creative Commons Attribution 4.0 International license
Persistent DSpace Link
DOI of Published Version
https://doi.org/10.1051/0004-6361/202244056
