TOI-2285b: A 1.7 Earth-radius planet near the habitable zone around a nearby M dwarf
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psab106.pdf
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Published version
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1.29 MB
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Adobe PDF
Checksum (MD5)
0772bd5c418edd48895c595b427b80d9
Author(s)
Seager, Sara
Date Issued
2022
Journal
Publications of the Astronomical Society of Japan
Publisher
Oxford University Press (OUP)
Citation
Seager, Sara. 2022. "TOI-2285b: A 1.7 Earth-radius planet near the habitable zone around a nearby M dwarf." Publications of the Astronomical Society of Japan, 74 (1).
Version
Final published version
Abstract
Abstract
We report the discovery of TOI-2285b, a sub-Neptune-sized planet transiting a nearby (42 pc) M dwarf with a period of 27.3 d. We identified the transit signal from the Transiting Exoplanet Survey Satellite photometric data, which we confirmed with ground-based photometric observations using the multiband imagers MuSCAT2 and MuSCAT3. Combining these data with other follow-up observations including high-resolution spectroscopy with the Tillinghast Reflector Echelle Spectrograph, high-resolution imaging with the SPeckle Polarimeter, and radial velocity (RV) measurements with the InfraRed Doppler instrument, we find that the planet has a radius of $1.74 \pm 0.08\, R_\oplus$, a mass of $\lt \!\!19.5\,M_\oplus$ ($95\%$ c.l.), and an insolation flux of 1.54 ± 0.14 times that of the Earth. Although the planet resides just outside the habitable zone for a rocky planet, if the planet harbors an H2O layer under a hydrogen-rich atmosphere, then liquid water could exist on the surface of the H2O layer depending on the planetary mass and water mass fraction. The bright host star in the near-infrared (Ks = 9.0) makes this planet an excellent target for further RV and atmospheric observations to improve our understanding of the composition, formation, and habitability of sub-Neptune-sized planets.
We report the discovery of TOI-2285b, a sub-Neptune-sized planet transiting a nearby (42 pc) M dwarf with a period of 27.3 d. We identified the transit signal from the Transiting Exoplanet Survey Satellite photometric data, which we confirmed with ground-based photometric observations using the multiband imagers MuSCAT2 and MuSCAT3. Combining these data with other follow-up observations including high-resolution spectroscopy with the Tillinghast Reflector Echelle Spectrograph, high-resolution imaging with the SPeckle Polarimeter, and radial velocity (RV) measurements with the InfraRed Doppler instrument, we find that the planet has a radius of $1.74 \pm 0.08\, R_\oplus$, a mass of $\lt \!\!19.5\,M_\oplus$ ($95\%$ c.l.), and an insolation flux of 1.54 ± 0.14 times that of the Earth. Although the planet resides just outside the habitable zone for a rocky planet, if the planet harbors an H2O layer under a hydrogen-rich atmosphere, then liquid water could exist on the surface of the H2O layer depending on the planetary mass and water mass fraction. The bright host star in the near-infrared (Ks = 9.0) makes this planet an excellent target for further RV and atmospheric observations to improve our understanding of the composition, formation, and habitability of sub-Neptune-sized planets.
MIT Department
Massachusetts Institute of Technology. Department of Earth, Atmospheric, and Planetary Sciences
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DOI of Published Version
https://doi.org/10.1093/PASJ/PSAB106
