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Discovery and characterisation of two exoplanets orbiting the metal-poor, solar-type star TOI-5788 with TESS, CHEOPS, and HARPS-N

Fuente: arXiv

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Detalles Bibliográficos
Autores principales:	Lakeland, Ben S., Mortier, A., Haywood, R. D., Ulmer-Moll, S., Garai, Z., Vanderburg, A., Egger, J A., Turner, D. A., Kubyshkina, D., Correia, A. C. M., Osborn, H. P., Buchhave, L. A., Malavolta, L., Bonfanti, A., Boschin, W., Cameron, A., Castro-González, A., Cosentino, R., Damasso, M., Dumusque, X., Ehrenreich, D., Essack, Z., Filomeno, S., Fossati, L., Gandolfi, D., Gillon, M., Hedges, C., López-Morales, M., Lacedelli, G., Lendl, M., Maldonado, J., Mantovan, G., Fiorenzano, A. F. Martínez, Maxted, P. F. L., Mordasini, C., Nicholson, B., O'Brien, S. M., Palethorpe, L., Palle, E., Pinamonti, M., Rapetti, D., Ribas, I., Santos, N. C., Silva, A. M., Sozzetti, A., Stalport, M., Szabó, G., Udry, S., Vezie, M., Watson, C. A., Wilson, T. G.
Formato:	Preprint
Publicado:	2026
Materias:	Earth and Planetary Astrophysics Solar and Stellar Astrophysics
Acceso en línea:	Acceder al recurso
Etiquetas:	Agregar Etiqueta Sin Etiquetas, Sea el primero en etiquetar este registro!

_version_	1866908776440791040
author	Lakeland, Ben S. Mortier, A. Haywood, R. D. Ulmer-Moll, S. Garai, Z. Vanderburg, A. Egger, J A. Turner, D. A. Kubyshkina, D. Correia, A. C. M. Osborn, H. P. Buchhave, L. A. Malavolta, L. Bonfanti, A. Boschin, W. Cameron, A. Castro-González, A. Cosentino, R. Damasso, M. Dumusque, X. Ehrenreich, D. Essack, Z. Filomeno, S. Fossati, L. Gandolfi, D. Gillon, M. Hedges, C. López-Morales, M. Lacedelli, G. Lendl, M. Maldonado, J. Mantovan, G. Fiorenzano, A. F. Martínez Maxted, P. F. L. Mordasini, C. Nicholson, B. O'Brien, S. M. Palethorpe, L. Palle, E. Pinamonti, M. Rapetti, D. Ribas, I. Santos, N. C. Silva, A. M. Sozzetti, A. Stalport, M. Szabó, G. Udry, S. Vezie, M. Watson, C. A. Wilson, T. G.
author_facet	Lakeland, Ben S. Mortier, A. Haywood, R. D. Ulmer-Moll, S. Garai, Z. Vanderburg, A. Egger, J A. Turner, D. A. Kubyshkina, D. Correia, A. C. M. Osborn, H. P. Buchhave, L. A. Malavolta, L. Bonfanti, A. Boschin, W. Cameron, A. Castro-González, A. Cosentino, R. Damasso, M. Dumusque, X. Ehrenreich, D. Essack, Z. Filomeno, S. Fossati, L. Gandolfi, D. Gillon, M. Hedges, C. López-Morales, M. Lacedelli, G. Lendl, M. Maldonado, J. Mantovan, G. Fiorenzano, A. F. Martínez Maxted, P. F. L. Mordasini, C. Nicholson, B. O'Brien, S. M. Palethorpe, L. Palle, E. Pinamonti, M. Rapetti, D. Ribas, I. Santos, N. C. Silva, A. M. Sozzetti, A. Stalport, M. Szabó, G. Udry, S. Vezie, M. Watson, C. A. Wilson, T. G.
contents	We present the discovery and characterisation of two transiting exoplanets orbiting the metal-poor, solar-type star TOI-5788. From our analysis of six \textit{TESS} sectors and a dedicated \textit{CHEOPS} programme, we identify an inner planet (TOI-5788~b; $P = 6.340758\pm0.000030\,\si{\day}$) with radius $1.528\pm0.075\,\mathrm{R_\oplus}$ and an outer planet (TOI-5788~c; $P = 16.213362\pm0.000026\,\si{\day}$) with radius $2.272\pm0.039\,\mathrm{R_\oplus}$. We obtained 125 radial-velocity spectra from HARPS-N and constrain the masses of TOI-5788~b and~c as $3.72\pm0.94\,\mathrm{M_\oplus}$ and $6.4\pm1.2\,\mathrm{M_\oplus}$, respectively. Although dynamical analyses indicate that a third planet could exist in a stable orbit between 8 and 14 days, we find no evidence of additional planets. Since the TOI-5788 system is one of the few systems with planets straddling the radius gap, and noting that there are even fewer such systems around metal poor stars, it is a promising system to constrain planet formation theories. We therefore model the interior structures of both planets. We find that TOI-5788~b is consistent with being a rocky planet with almost no envelope, or having an atmosphere of a high mean molecular weight. We find that TOI-5788~c is consistent with both gas-dwarf and water-world hypotheses of mini-Neptune formation. We model the atmospheric evolution history of both planets. Whilst both scenarios are consistent with the atmospheric evolution of TOI-5788~c, the gas-dwarf model is marginally preferred. The results of the atmospheric evolution analysis are not strongly dependent on stellar evolution. This makes the system a promising target to test internal structure and atmospheric evolution models.
format	Preprint
id	arxiv_https___arxiv_org_abs_2601_14045
institution	arXiv
publishDate	2026
record_format	arxiv
spellingShingle	Discovery and characterisation of two exoplanets orbiting the metal-poor, solar-type star TOI-5788 with TESS, CHEOPS, and HARPS-N Lakeland, Ben S. Mortier, A. Haywood, R. D. Ulmer-Moll, S. Garai, Z. Vanderburg, A. Egger, J A. Turner, D. A. Kubyshkina, D. Correia, A. C. M. Osborn, H. P. Buchhave, L. A. Malavolta, L. Bonfanti, A. Boschin, W. Cameron, A. Castro-González, A. Cosentino, R. Damasso, M. Dumusque, X. Ehrenreich, D. Essack, Z. Filomeno, S. Fossati, L. Gandolfi, D. Gillon, M. Hedges, C. López-Morales, M. Lacedelli, G. Lendl, M. Maldonado, J. Mantovan, G. Fiorenzano, A. F. Martínez Maxted, P. F. L. Mordasini, C. Nicholson, B. O'Brien, S. M. Palethorpe, L. Palle, E. Pinamonti, M. Rapetti, D. Ribas, I. Santos, N. C. Silva, A. M. Sozzetti, A. Stalport, M. Szabó, G. Udry, S. Vezie, M. Watson, C. A. Wilson, T. G. Earth and Planetary Astrophysics Solar and Stellar Astrophysics We present the discovery and characterisation of two transiting exoplanets orbiting the metal-poor, solar-type star TOI-5788. From our analysis of six \textit{TESS} sectors and a dedicated \textit{CHEOPS} programme, we identify an inner planet (TOI-5788~b; $P = 6.340758\pm0.000030\,\si{\day}$) with radius $1.528\pm0.075\,\mathrm{R_\oplus}$ and an outer planet (TOI-5788~c; $P = 16.213362\pm0.000026\,\si{\day}$) with radius $2.272\pm0.039\,\mathrm{R_\oplus}$. We obtained 125 radial-velocity spectra from HARPS-N and constrain the masses of TOI-5788~b and~c as $3.72\pm0.94\,\mathrm{M_\oplus}$ and $6.4\pm1.2\,\mathrm{M_\oplus}$, respectively. Although dynamical analyses indicate that a third planet could exist in a stable orbit between 8 and 14 days, we find no evidence of additional planets. Since the TOI-5788 system is one of the few systems with planets straddling the radius gap, and noting that there are even fewer such systems around metal poor stars, it is a promising system to constrain planet formation theories. We therefore model the interior structures of both planets. We find that TOI-5788~b is consistent with being a rocky planet with almost no envelope, or having an atmosphere of a high mean molecular weight. We find that TOI-5788~c is consistent with both gas-dwarf and water-world hypotheses of mini-Neptune formation. We model the atmospheric evolution history of both planets. Whilst both scenarios are consistent with the atmospheric evolution of TOI-5788~c, the gas-dwarf model is marginally preferred. The results of the atmospheric evolution analysis are not strongly dependent on stellar evolution. This makes the system a promising target to test internal structure and atmospheric evolution models.
title	Discovery and characterisation of two exoplanets orbiting the metal-poor, solar-type star TOI-5788 with TESS, CHEOPS, and HARPS-N
topic	Earth and Planetary Astrophysics Solar and Stellar Astrophysics
url	https://arxiv.org/abs/2601.14045