TESS and HARPS-N Unveil Two Planets Transiting TOI-1453. A Super-Earth and One of the Lowest Mass sub-Neptunes
We report on the validation and characterisation of two transiting planets around TOI-1453, a K-dwarf star in the TESS northern continuous viewing zone. In addition to the TESS data, we used ground-based photometric, spectroscopic, and high-resolution imaging follow-up observations to validate the two planets.
We obtained 100 HARPS-N high-resolution spectra over two seasons and used them together with the TESS light curve to constrain the mass, radius, and orbit of each planet.
TOI-1453 b is a super-Earth with an orbital period of Pb=4.314 days, a radius of Rb=1.17±0.06R⊕, and a mass lower than 2.32M⊕ (99%). TOI-1453 c is a sub-Neptune with a period of Pc=6.589 days, radius of Rc=2.22±0.09R⊕, and mass of Mc=2.95±0.84M⊕. The two planets orbit TOI-1453 with a period ratio close to 3/2, although they are not in a mean motion resonance (MMR) state.
We did not detect any transit timing variations in our attempt to further constrain the planet masses. TOI-1453 c has a very low bulk density and is one of the least massive sub-Neptunes discovered to date.
It is compatible with having either a water-rich composition or a rocky core surrounded by a thick H/He atmosphere. However, we set constraints on the water mass fraction in the envelope according to either a water-rich or water-poor formation scenario. The star TOI-1453 belongs to the Galactic thin disc based on Gaia kinematics and has a sub-solar metallicity.
This system is orbited by a fainter stellar companion at a projected distance of about 150 AU, classifying TOI-1453 b and c of S-type planets. These various planetary and stellar characteristics make TOI-1453 a valuable system for understanding the origin of super-Earths and sub-Neptunes.
M. Stalport, A. Mortier, M. Cretignier, J.A. Egger, L. Malavolta, D. W. Latham, K. A. Collins, C. N. Watkins, F. Murgas, L. A. Buchhave, M. López-Morales, S. Udry, S. N. Quinn, A. M. Silva, G. Andreuzzi, D. Baker, W. Boschin, D. R. Ciardi, M. Damasso, L. Di Fabrizio, X. Dumusque, A. Fukui, R. Haywood, S. B. Howell, J. M. Jenkins, A. Leleu, P. Lewin, J. Lillo-Box, A. F. Martínez Fiorenzano, N. Narita, M. Pedani, M. Pinamonti, E. Poretti, R. P. Schwarz, S. Seager, A. Sozzetti, E. B. Ting, A. Vanderburg, J. N. Winn, C. Ziegler
Comments: 23 pages. Accepted for publication in A&A
Subjects: Earth and Planetary Astrophysics (astro-ph.EP)
Cite as: arXiv:2503.07529 [astro-ph.EP] (or arXiv:2503.07529v1 [astro-ph.EP] for this version)
https://doi.org/10.48550/arXiv.2503.07529
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Related DOI:
https://doi.org/10.1051/0004-6361/202452969
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Submission history
From: Manu Stalport
[v1] Mon, 10 Mar 2025 16:57:09 UTC (5,150 KB)
https://arxiv.org/abs/2503.07529
Astrobiology,
