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 <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:mi>λ</mml:mi> <mml:mo>=</mml:mo> <mml:mo>−</mml:mo> <mml:msubsup> <mml:mn>15</mml:mn> <mml:mrow> <mml:mo>−</mml:mo> <mml:mn>44</mml:mn> </mml:mrow> <mml:mrow> <mml:mo>+</mml:mo> <mml:mn>50</mml:mn> </mml:mrow> </mml:msubsup> </mml:math> ° (∣ λ ∣ < 80° at 3 σ ). 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.
Authors
- Cristóbal Petrovich (ORCID: https://orcid.org/0000-0003-0412-9314)
- F. Bouchy (ORCID: https://orcid.org/0000-0002-7613-393X)
- Maximilian N. Günther (ORCID: https://orcid.org/0000-0002-3164-9086)
- Jan Eberhardt (ORCID: https://orcid.org/0000-0003-3130-2768)
- Marcelo Tala Pinto (ORCID: https://orcid.org/0009-0004-8891-4057)
- Soléne Ulmer-Moll (ORCID: https://orcid.org/0000-0003-2417-7006)
- M. Lendl (ORCID: https://orcid.org/0000-0001-9699-1459)
- M. Catelan (ORCID: https://orcid.org/0000-0001-6003-8877)
- Rafael Brahm (ORCID: https://orcid.org/0000-0002-9158-7315)
- Carolina Charalambous (ORCID: https://orcid.org/0000-0002-9196-5734)
- A. Agabi (ORCID: https://orcid.org/0000-0001-7948-6493)
- T. Guillot (ORCID: https://orcid.org/0000-0002-7188-8428)
- A. H. M. J. Triaud (ORCID: https://orcid.org/0000-0002-5510-8751)
- F. X. Schmider (ORCID: https://orcid.org/0000-0003-3914-3546)
- Mathilde Timmermans (ORCID: https://orcid.org/0009-0008-2214-5039)
- Elyar Sedaghati (ORCID: https://orcid.org/0000-0002-7444-5315)
- Néstor Espinoza (ORCID: https://orcid.org/0000-0001-9513-1449)
- Andrés Jordán (ORCID: https://orcid.org/0000-0002-5389-3944)
- Carl Ziegler (ORCID: https://orcid.org/0000-0002-0619-7639)
- Guđmundur Stefánsson (ORCID: https://orcid.org/0000-0001-7409-5688)
- Louise D. Nielsen (ORCID: https://orcid.org/0000-0002-5254-2499)
- Trifon Trifonov (ORCID: https://orcid.org/0000-0002-0236-775X)
- Stephanie Striegel (ORCID: https://orcid.org/0009-0008-5145-0446)
- Thomas Henning (ORCID: https://orcid.org/0000-0002-1493-300X)
- Mélissa J. Hobson (ORCID: https://orcid.org/0000-0002-5945-7975)
- Erika Rea
- Felipe Rojas (ORCID: https://orcid.org/0000-0003-3047-6272)
- S. Udry (ORCID: https://orcid.org/0000-0001-7576-6236)
- Hareesh Gautham Bhaskar (ORCID: https://orcid.org/0000-0002-5181-0463)
- Diego J. Muñoz (ORCID: https://orcid.org/0000-0003-2186-234X)
- Philippe Bendjoya (ORCID: https://orcid.org/0000-0002-4278-1437)
- D. Mékarnia (ORCID: https://orcid.org/0000-0001-5000-7292)
- Juan I. Espinoza-Retamal (ORCID: https://orcid.org/0000-0001-9480-8526)
- Alix Violet Freckelton (ORCID: https://orcid.org/0009-0007-1053-0004)
- Olga Suárez
- George Dransfield
- M. I. Jones
- Joshua N. Winn (ORCID: https://orcid.org/0000-0002-4265-047X)
- Vincent Deloupy
Publication Details
- Journal
- The Astrophysical Journal Letters
- Published
- 2025-12-30
- DOI
- https://doi.org/10.3847/2041-8213/ae2bfa
- Primary Topic
- Astro and Planetary Science
- Type
- article
- Field-Weighted Citation Impact
- 0.00