A Cold and Superpuffy Planet on a Prograde Orbit

Juan I. Espinoza-Retamal; Rafael Brahm; Cristobal Petrovich; Andrés Jordán; Thomas Henning; Trifon Trifonov; Joshua N. Winn; Erika Rea; Maximilian N. Günther; Abdelkrim Agabi; Philippe Bendjoya; Hareesh Bhaskar; François Bouchy; Márcio Catelan; Carolina Charalambous; Vincent Deloupy; George Dransfield; Jan Eberhardt; Néstor Espinoza; Alix V. Freckelton; Tristan Guillot; Melissa J. Hobson; Matías I. Jones; Monika Lendl; Djamel Mekarnia; Diego J. Muñoz; Louise D. Nielsen; Felipe I. Rojas; François Xavier Schmider; Elyar Sedaghati; Guđmundur Stefánsson; Stephanie Striegel; Olga Suarez; Marcelo Tala Pinto; Mathilde Timmermans; Amaury H.M.J. Triaud; Stéphane Udry; Solène Ulmer-Moll; Carl Ziegler

doi:10.3847/2041-8213/ae2bfa

A Cold and Superpuffy Planet on a Prograde Orbit

Juan I. Espinoza-Retamal
, Rafael Brahm
, Cristobal Petrovich
, Andrés Jordán
, Thomas Henning
, Trifon Trifonov
, Joshua N. Winn
, Erika Rea
, Maximilian N. Günther
, Abdelkrim Agabi
, Philippe Bendjoya
, Hareesh Bhaskar
, François Bouchy
, Márcio Catelan
, Carolina Charalambous
, Vincent Deloupy
, George Dransfield
, Jan Eberhardt
, Néstor Espinoza
, Alix V. Freckelton

Tristan Guillot, Melissa J. Hobson, Matías I. Jones, Monika Lendl, Djamel Mekarnia, Diego J. Muñoz, Louise D. Nielsen, Felipe I. Rojas, François Xavier Schmider, Elyar Sedaghati, Guđmundur Stefánsson, Stephanie Striegel, Olga Suarez, Marcelo Tala Pinto, Mathilde Timmermans, Amaury H.M.J. Triaud, Stéphane Udry, Solène Ulmer-Moll, Carl Ziegler

Astronomy and Planetary Sciences

Research output: Contribution to journal › Article › peer-review

2 Scopus citations

Abstract

We report the discovery of TOI-4507 b, a transiting sub-Saturn with a density <0.2 g cm⁻³ on a 105 days prograde orbit around a 700 Myr old F star. The transits were detected using data from TESS as well as the Antarctic telescope ASTEP. A joint analysis of the light curves and radial velocities from HARPS, FEROS, and CORALIE confirmed the planetary nature of the signal, by limiting the mass to be below 20 M_⊕ at 95% confidence. The radial velocities also exhibit the Rossiter-McLaughlin effect and imply that the planet orbits the star in a prograde orbit with a sky-projected obliquity λ = − 15 − 44 + 50 ° (∣λ∣ < 80° at 3σ). With these characteristics, TOI-4507 is one of the longest-period systems for which the stellar obliquity has been measured, and the planet is among the longest-period and youngest “superpuff” planets yet discovered.

Original language	English (US)
Article number	L13
Journal	Astrophysical Journal Letters
Volume	996
Issue number	1
DOIs	https://doi.org/10.3847/2041-8213/ae2bfa
State	Published - Jan 1 2026

ASJC Scopus subject areas

Astronomy and Astrophysics
Space and Planetary Science

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10.3847/2041-8213/ae2bfa

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Espinoza-Retamal, J. I., Brahm, R., Petrovich, C., Jordán, A., Henning, T., Trifonov, T., Winn, J. N., Rea, E., Günther, M. N., Agabi, A., Bendjoya, P., Bhaskar, H., Bouchy, F., Catelan, M., Charalambous, C., Deloupy, V., Dransfield, G., Eberhardt, J., Espinoza, N., ... Ziegler, C. (2026). A Cold and Superpuffy Planet on a Prograde Orbit. Astrophysical Journal Letters, 996(1), Article L13. https://doi.org/10.3847/2041-8213/ae2bfa

Espinoza-Retamal, JI, Brahm, R, Petrovich, C, Jordán, A, Henning, T, Trifonov, T, Winn, JN, Rea, E, Günther, MN, Agabi, A, Bendjoya, P, Bhaskar, H, Bouchy, F, Catelan, M, Charalambous, C, Deloupy, V, Dransfield, G, Eberhardt, J, Espinoza, N, Freckelton, AV, Guillot, T, Hobson, MJ, Jones, MI, Lendl, M, Mekarnia, D, Muñoz, DJ, D. Nielsen, L, Rojas, FI, Schmider, FX, Sedaghati, E, Stefánsson, G, Striegel, S, Suarez, O, Tala Pinto, M, Timmermans, M, Triaud, AHMJ, Udry, S, Ulmer-Moll, S & Ziegler, C 2026, 'A Cold and Superpuffy Planet on a Prograde Orbit', Astrophysical Journal Letters, vol. 996, no. 1, L13. https://doi.org/10.3847/2041-8213/ae2bfa

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title = "A Cold and Superpuffy Planet on a Prograde Orbit",

abstract = "We report the discovery of TOI-4507 b, a transiting sub-Saturn with a density <0.2 g cm−3 on a 105 days prograde orbit around a 700 Myr old F star. The transits were detected using data from TESS as well as the Antarctic telescope ASTEP. A joint analysis of the light curves and radial velocities from HARPS, FEROS, and CORALIE confirmed the planetary nature of the signal, by limiting the mass to be below 20 M⊕ at 95\% confidence. The radial velocities also exhibit the Rossiter-McLaughlin effect and imply that the planet orbits the star in a prograde orbit with a sky-projected obliquity λ = − 15 − 44 + 50 ° (∣λ∣ < 80° at 3σ). With these characteristics, TOI-4507 is one of the longest-period systems for which the stellar obliquity has been measured, and the planet is among the longest-period and youngest “superpuff” planets yet discovered.",

author = "Espinoza-Retamal, \{Juan I.\} and Rafael Brahm and Cristobal Petrovich and Andr{\'e}s Jord{\'a}n and Thomas Henning and Trifon Trifonov and Winn, \{Joshua N.\} and Erika Rea and G{\"u}nther, \{Maximilian N.\} and Abdelkrim Agabi and Philippe Bendjoya and Hareesh Bhaskar and Fran{\c c}ois Bouchy and M{\'a}rcio Catelan and Carolina Charalambous and Vincent Deloupy and George Dransfield and Jan Eberhardt and N{\'e}stor Espinoza and Freckelton, \{Alix V.\} and Tristan Guillot and Hobson, \{Melissa J.\} and Jones, \{Mat{\'i}as I.\} and Monika Lendl and Djamel Mekarnia and Mu{\~n}oz, \{Diego J.\} and \{D. Nielsen\}, Louise and Rojas, \{Felipe I.\} and Schmider, \{Fran{\c c}ois Xavier\} and Elyar Sedaghati and Gu{\d}mundur Stef{\'a}nsson and Stephanie Striegel and Olga Suarez and \{Tala Pinto\}, Marcelo and Mathilde Timmermans and Triaud, \{Amaury H.M.J.\} and St{\'e}phane Udry and Sol{\`e}ne Ulmer-Moll and Carl Ziegler",

note = "Publisher Copyright: {\textcopyright} 2025. The Author(s). Published by the American Astronomical Society.",

year = "2026",

month = jan,

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doi = "10.3847/2041-8213/ae2bfa",

language = "English (US)",

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T1 - A Cold and Superpuffy Planet on a Prograde Orbit

AU - Espinoza-Retamal, Juan I.

AU - Brahm, Rafael

AU - Petrovich, Cristobal

AU - Jordán, Andrés

AU - Henning, Thomas

AU - Trifonov, Trifon

AU - Winn, Joshua N.

AU - Rea, Erika

AU - Günther, Maximilian N.

AU - Agabi, Abdelkrim

AU - Bendjoya, Philippe

AU - Bhaskar, Hareesh

AU - Bouchy, François

AU - Catelan, Márcio

AU - Charalambous, Carolina

AU - Deloupy, Vincent

AU - Dransfield, George

AU - Eberhardt, Jan

AU - Espinoza, Néstor

AU - Freckelton, Alix V.

AU - Guillot, Tristan

AU - Hobson, Melissa J.

AU - Jones, Matías I.

AU - Lendl, Monika

AU - Mekarnia, Djamel

AU - Muñoz, Diego J.

AU - D. Nielsen, Louise

AU - Rojas, Felipe I.

AU - Schmider, François Xavier

AU - Sedaghati, Elyar

AU - Stefánsson, Guđmundur

AU - Striegel, Stephanie

AU - Suarez, Olga

AU - Tala Pinto, Marcelo

AU - Timmermans, Mathilde

AU - Triaud, Amaury H.M.J.

AU - Udry, Stéphane

AU - Ulmer-Moll, Solène

AU - Ziegler, Carl

PY - 2026/1/1

Y1 - 2026/1/1

N2 - We report the discovery of TOI-4507 b, a transiting sub-Saturn with a density <0.2 g cm−3 on a 105 days prograde orbit around a 700 Myr old F star. The transits were detected using data from TESS as well as the Antarctic telescope ASTEP. A joint analysis of the light curves and radial velocities from HARPS, FEROS, and CORALIE confirmed the planetary nature of the signal, by limiting the mass to be below 20 M⊕ at 95% confidence. The radial velocities also exhibit the Rossiter-McLaughlin effect and imply that the planet orbits the star in a prograde orbit with a sky-projected obliquity λ = − 15 − 44 + 50 ° (∣λ∣ < 80° at 3σ). With these characteristics, TOI-4507 is one of the longest-period systems for which the stellar obliquity has been measured, and the planet is among the longest-period and youngest “superpuff” planets yet discovered.

AB - We report the discovery of TOI-4507 b, a transiting sub-Saturn with a density <0.2 g cm−3 on a 105 days prograde orbit around a 700 Myr old F star. The transits were detected using data from TESS as well as the Antarctic telescope ASTEP. A joint analysis of the light curves and radial velocities from HARPS, FEROS, and CORALIE confirmed the planetary nature of the signal, by limiting the mass to be below 20 M⊕ at 95% confidence. The radial velocities also exhibit the Rossiter-McLaughlin effect and imply that the planet orbits the star in a prograde orbit with a sky-projected obliquity λ = − 15 − 44 + 50 ° (∣λ∣ < 80° at 3σ). With these characteristics, TOI-4507 is one of the longest-period systems for which the stellar obliquity has been measured, and the planet is among the longest-period and youngest “superpuff” planets yet discovered.

UR - https://www.scopus.com/pages/publications/105033822075

UR - https://www.scopus.com/pages/publications/105033822075#tab=citedBy

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DO - 10.3847/2041-8213/ae2bfa

M3 - Article

AN - SCOPUS:105033822075

SN - 2041-8205

VL - 996

JO - Astrophysical Journal Letters

JF - Astrophysical Journal Letters

IS - 1

M1 - L13

ER -

A Cold and Superpuffy Planet on a Prograde Orbit

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