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TESS and ESPRESSO discover a super-Earth and a mini-Neptune orbiting the K-dwarf TOI-238

Fuente: arXiv

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Main Authors:	Mascareño, A. Suárez, Passegger, V. M., Hernández, J. I. González, Armstrong, D. J., Nielsen, L. D., Lovis, C., Lavie, B., Sousa, S. G., Silva, A. M., Allart, R., Rebolo, R., Pepe, F., Santos, N. C., Cristiani, S., Sozzetti, A., Osorio, M. R. Zapatero, Tabernero, H. M., Dumusque, X., Udry, S., Adibekyan, V., Prieto, C. Allende, Alibert, Y., Barros, S. C. C., Bouchy, F., Castro-González, A., Collins, K. A., Damasso, M., D'Odorico, V., Demangeon, O. D. S., Di Marcantonio, P., Ehrenreich, D., Hadjigeorghiou, A., Hara, N., Hawthorn, F., Jenkins, J. M., Lillo-Box, J., Curto, G. Lo, Martins, C. J. A. P., Mehner, A., Micela, G., Molaro, P., Nunes, N., Nari, N., Osborn, A., Pallé, E., Ricker, G. R., Rodrigues, J., Rowden, P., Seager, S., Stefanov, A. K., Strøm, P. A., Villaseñor, J. N. S., Watkins, C. N., Winn, J., Wohler, B., Zambelli, R.
Format:	Preprint
Published:	2024
Subjects:	Earth and Planetary Astrophysics
Online Access:	Acceder al recurso
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_version_	1866909095589576704
author	Mascareño, A. Suárez Passegger, V. M. Hernández, J. I. González Armstrong, D. J. Nielsen, L. D. Lovis, C. Lavie, B. Sousa, S. G. Silva, A. M. Allart, R. Rebolo, R. Pepe, F. Santos, N. C. Cristiani, S. Sozzetti, A. Osorio, M. R. Zapatero Tabernero, H. M. Dumusque, X. Udry, S. Adibekyan, V. Prieto, C. Allende Alibert, Y. Barros, S. C. C. Bouchy, F. Castro-González, A. Collins, K. A. Damasso, M. D'Odorico, V. Demangeon, O. D. S. Di Marcantonio, P. Ehrenreich, D. Hadjigeorghiou, A. Hara, N. Hawthorn, F. Jenkins, J. M. Lillo-Box, J. Curto, G. Lo Martins, C. J. A. P. Mehner, A. Micela, G. Molaro, P. Nunes, N. Nari, N. Osborn, A. Pallé, E. Ricker, G. R. Rodrigues, J. Rowden, P. Seager, S. Stefanov, A. K. Strøm, P. A. Villaseñor, J. N. S. Watkins, C. N. Winn, J. Wohler, B. Zambelli, R.
author_facet	Mascareño, A. Suárez Passegger, V. M. Hernández, J. I. González Armstrong, D. J. Nielsen, L. D. Lovis, C. Lavie, B. Sousa, S. G. Silva, A. M. Allart, R. Rebolo, R. Pepe, F. Santos, N. C. Cristiani, S. Sozzetti, A. Osorio, M. R. Zapatero Tabernero, H. M. Dumusque, X. Udry, S. Adibekyan, V. Prieto, C. Allende Alibert, Y. Barros, S. C. C. Bouchy, F. Castro-González, A. Collins, K. A. Damasso, M. D'Odorico, V. Demangeon, O. D. S. Di Marcantonio, P. Ehrenreich, D. Hadjigeorghiou, A. Hara, N. Hawthorn, F. Jenkins, J. M. Lillo-Box, J. Curto, G. Lo Martins, C. J. A. P. Mehner, A. Micela, G. Molaro, P. Nunes, N. Nari, N. Osborn, A. Pallé, E. Ricker, G. R. Rodrigues, J. Rowden, P. Seager, S. Stefanov, A. K. Strøm, P. A. Villaseñor, J. N. S. Watkins, C. N. Winn, J. Wohler, B. Zambelli, R.
contents	The number of super-Earth and mini-Neptune planet discoveries has increased significantly in the last two decades thanks to transit and radial velocity surveys. When it is possible to apply both techniques, we can characterise the internal composition of exoplanets, which in turn provides unique insights on their architecture, formation and evolution. We performed a combined photometric and radial velocity analysis of TOI-238 (TYC 6398-132-1), which has one short-orbit super-Earth planet candidate announced by NASA's TESS team. We aim to confirm its planetary nature using radial velocities taken with the ESPRESSO and HARPS spectrographs, to measure its mass and to detect the presence of other possible planetary companions. We carried out a joint analysis by including Gaussian processes and Keplerian orbits to account for the stellar activity and planetary signals simultaneously. We detected the signal induced by TOI-238 b in the radial velocity time-series, and the presence of a second transiting planet, TOI-238 c, whose signal appears in RV and TESS data. TOI-238 b is a planet with a radius of 1.402$^{+0.084}_{-0.086}$ R$_{\oplus}$ and a mass of 3.40$^{+0.46}_{-0.45}$ M$_{\oplus}$. It orbits at a separation of 0.02118 $\pm$ 0.00038 AU of its host star, with an orbital period of 1.2730988 $\pm$ 0.0000029 days, and has an equilibrium temperature of 1311 $\pm$ 28 K. TOI-238 c has a radius of 2.18$\pm$ 0.18 R$_{\oplus}$ and a mass of 6.7 $\pm$ 1.1 M$_{\oplus}$. It orbits at a separation of 0.0749 $\pm$ 0.0013 AU of its host star, with an orbital period of 8.465652 $\pm$ 0.000031 days, and has an equilibrium temperature of 696 $\pm$ 15 K. The mass and radius of planet b are fully consistent with an Earth-like composition, making it likely a rocky super-Earth. Planet c could be a water-rich planet or a rocky planet with a small H-He atmosphere.
format	Preprint
id	arxiv_https___arxiv_org_abs_2402_04113
institution	arXiv
publishDate	2024
record_format	arxiv
spellingShingle	TESS and ESPRESSO discover a super-Earth and a mini-Neptune orbiting the K-dwarf TOI-238 Mascareño, A. Suárez Passegger, V. M. Hernández, J. I. González Armstrong, D. J. Nielsen, L. D. Lovis, C. Lavie, B. Sousa, S. G. Silva, A. M. Allart, R. Rebolo, R. Pepe, F. Santos, N. C. Cristiani, S. Sozzetti, A. Osorio, M. R. Zapatero Tabernero, H. M. Dumusque, X. Udry, S. Adibekyan, V. Prieto, C. Allende Alibert, Y. Barros, S. C. C. Bouchy, F. Castro-González, A. Collins, K. A. Damasso, M. D'Odorico, V. Demangeon, O. D. S. Di Marcantonio, P. Ehrenreich, D. Hadjigeorghiou, A. Hara, N. Hawthorn, F. Jenkins, J. M. Lillo-Box, J. Curto, G. Lo Martins, C. J. A. P. Mehner, A. Micela, G. Molaro, P. Nunes, N. Nari, N. Osborn, A. Pallé, E. Ricker, G. R. Rodrigues, J. Rowden, P. Seager, S. Stefanov, A. K. Strøm, P. A. Villaseñor, J. N. S. Watkins, C. N. Winn, J. Wohler, B. Zambelli, R. Earth and Planetary Astrophysics The number of super-Earth and mini-Neptune planet discoveries has increased significantly in the last two decades thanks to transit and radial velocity surveys. When it is possible to apply both techniques, we can characterise the internal composition of exoplanets, which in turn provides unique insights on their architecture, formation and evolution. We performed a combined photometric and radial velocity analysis of TOI-238 (TYC 6398-132-1), which has one short-orbit super-Earth planet candidate announced by NASA's TESS team. We aim to confirm its planetary nature using radial velocities taken with the ESPRESSO and HARPS spectrographs, to measure its mass and to detect the presence of other possible planetary companions. We carried out a joint analysis by including Gaussian processes and Keplerian orbits to account for the stellar activity and planetary signals simultaneously. We detected the signal induced by TOI-238 b in the radial velocity time-series, and the presence of a second transiting planet, TOI-238 c, whose signal appears in RV and TESS data. TOI-238 b is a planet with a radius of 1.402$^{+0.084}_{-0.086}$ R$_{\oplus}$ and a mass of 3.40$^{+0.46}_{-0.45}$ M$_{\oplus}$. It orbits at a separation of 0.02118 $\pm$ 0.00038 AU of its host star, with an orbital period of 1.2730988 $\pm$ 0.0000029 days, and has an equilibrium temperature of 1311 $\pm$ 28 K. TOI-238 c has a radius of 2.18$\pm$ 0.18 R$_{\oplus}$ and a mass of 6.7 $\pm$ 1.1 M$_{\oplus}$. It orbits at a separation of 0.0749 $\pm$ 0.0013 AU of its host star, with an orbital period of 8.465652 $\pm$ 0.000031 days, and has an equilibrium temperature of 696 $\pm$ 15 K. The mass and radius of planet b are fully consistent with an Earth-like composition, making it likely a rocky super-Earth. Planet c could be a water-rich planet or a rocky planet with a small H-He atmosphere.
title	TESS and ESPRESSO discover a super-Earth and a mini-Neptune orbiting the K-dwarf TOI-238
topic	Earth and Planetary Astrophysics
url	https://arxiv.org/abs/2402.04113