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arXiv · 2512.06841

TOI-7166 b: A Habitable Zone mini-Neptune planet around a nearby low-mass star

Khalid Barkaoui·Francisco J. Pozuelos·Benjamin V. Rackham·Adam J. Burgasser·Amaury H. M. J. Triaud·Miquel Serra-Ricart·Mathilde Timmermans·Selçuk. Yalçınkaya·Abderahmane Soubkiou·Keivan G. Stassun·Karen A. Collins·Pedro J. Amado·Özgur Baştürk·Artem Burdanov·Yasmin T. Davis·Julien de Wit·Brice-Olivier Demory·Sarah Deveny·Georgina Dransfield·Elsa Ducrot·Michaël Gillon·Yilen Gómez Maqueo Chew·Matthew J. Hooton·Keith Horne·Steve B. Howell·Clàudia Janó Muñoz·Emmanuel Jehin·John M. Jenkins·Colin Littlefield·Eduardo L. Martín·Prajwal Niraula·Peter P. Pedersen·Dedier Queloz·Madison G. Scott·Ramotholo Sefako·Avi Shporer·Christopher Stockdale·Emma Softich·Alfredo Sota·Benjamin Tofflemire·Özlem Şimşir·Roberto Varas·Francis Zong Lang·Sebastián S. Zúñiga-Fernández
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Abstract

We present the discovery and validation of TOI-7166b, a 2.01+/-0.05R_Earth planet orbiting a nearby low-mass star. We validated the planet by combining TESS and multi-color high-precision photometric observations from ground-based telescopes, together with spectroscopic data, high-contrast imaging, archival images, and statistical arguments. The host star is an M4-type dwarf at a distance of ~35 pc from the Sun. It has a mass and a radius of Ms=0.190+/-0.004M_Sun and Rs=0.222+/-0.005R_Sun, respectively. TOI-7166b has an orbital period of 12.9 days, which places it close to the inner edge of the Habitable Zone of its host star, receiving an insolation flux of Sp=1.07+/-0.08S_Earth and an equilibrium temperature of Teq=249+/-5K (assuming a null Bond albedo). The brightness of the host star makes TOI-7166 a suitable target for radial velocity follow-up to measure the planetary mass and bulk density. Moreover, the physical parameters of the system including the infrared brightness (Kmag = 10.6) of the star and the planet-to-star radius ratio (0.0823+/-0.0012) make TOI-7166b an exquisite target for transmission spectroscopic observations with the JWST, to constrain the exoplanet atmospheric compositions.

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Khalid Barkaoui, Francisco J. Pozuelos, Benjamin V. Rackham, Adam J. Burgasser, Amaury H. M. J. Triaud, Miquel Serra-Ricart, Mathilde Timmermans, Selçuk. Yalçınkaya, Abderahmane Soubkiou, Keivan G. Stassun, Karen A. Collins, Pedro J. Amado, Özgur Baştürk, Artem Burdanov, Yasmin T. Davis, Julien de Wit, Brice-Olivier Demory, Sarah Deveny, Georgina Dransfield, Elsa Ducrot, Michaël Gillon, Yilen Gómez Maqueo Chew, Matthew J. Hooton, Keith Horne, Steve B. Howell, Clàudia Janó Muñoz, Emmanuel Jehin, John M. Jenkins, Colin Littlefield, Eduardo L. Martín, Prajwal Niraula, Peter P. Pedersen, Dedier Queloz, Madison G. Scott, Ramotholo Sefako, Avi Shporer, Christopher Stockdale, Emma Softich, Alfredo Sota, Benjamin Tofflemire, Özlem Şimşir, Roberto Varas, Francis Zong Lang, Sebastián S. Zúñiga-Fernández. 2025-12-07. TOI-7166 b: A Habitable Zone mini-Neptune planet around a nearby low-mass star. https://doi.org/10.1093/mnras%2Fstaf1807

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