TOI-2458 b : A mini-Neptune consistent with in situ hot Jupiter formation
(2025) In Astronomy and Astrophysics 693.- Abstract
We report on the discovery and spectroscopic confirmation of TOI-2458 b, a transiting mini-Neptune around an F-type star leaving the main-sequence with a mass of M∗ = 1.05 ± 0.03 M⊙, a radius of R∗ = 1.31 ± 0.03 R⊙, an effective temperature of Teff = 6005 ± 50 K, and a metallicity of 0.10 ± 0.05 dex. By combining TESS photometry with high-resolution spectra acquired with the HARPS spectrograph, we found that the transiting planet has an orbital period of 3.74 days, a mass of Mp = 13.31 ± 0.99 M⊕ and a radius of Rp = 2.83 ± 0.20 R⊕. The host star TOI-2458 shows a short activity cycle of ∼54 days revealed in the HARPS S-index and Ha times... (More)
We report on the discovery and spectroscopic confirmation of TOI-2458 b, a transiting mini-Neptune around an F-type star leaving the main-sequence with a mass of M∗ = 1.05 ± 0.03 M⊙, a radius of R∗ = 1.31 ± 0.03 R⊙, an effective temperature of Teff = 6005 ± 50 K, and a metallicity of 0.10 ± 0.05 dex. By combining TESS photometry with high-resolution spectra acquired with the HARPS spectrograph, we found that the transiting planet has an orbital period of 3.74 days, a mass of Mp = 13.31 ± 0.99 M⊕ and a radius of Rp = 2.83 ± 0.20 R⊕. The host star TOI-2458 shows a short activity cycle of ∼54 days revealed in the HARPS S-index and Ha times series. We took the opportunity to investigate other F stars showing activity cycle periods comparable to that of TOI-2458 and found that they have shorter rotation periods than would be expected based on the gyrochronology predictions. In addition, we determined TOI-2458's stellar inclination angle to be i∗ = 10.610.6+13.3 degrees. We discuss that both phenomena (fast stellar rotation and planet orbit inclination) could be explained by in situ formation of a hot Jupiter interior to TOI-2458 b. It is plausible that this hot Jupiter was recently engulfed by the star. Analysis of HARPS spectra has identified the presence of another planet with a period of P = 16.55 ± 0.06 days and a minimum mass of Mp sin i = 10.22 ± 1.90 M⊕.
(Less)
- author
- organization
- publishing date
- 2025-01-01
- type
- Contribution to journal
- publication status
- published
- subject
- keywords
- Planetary systems, Planets and satellites: dynamical evolution and stability, Planets and satellites: formation, Techniques: photometric, Techniques: radial velocities, Techniques: spectroscopic
- in
- Astronomy and Astrophysics
- volume
- 693
- article number
- A235
- publisher
- EDP Sciences
- external identifiers
-
- scopus:85216404674
- ISSN
- 0004-6361
- DOI
- 10.1051/0004-6361/202451057
- language
- English
- LU publication?
- yes
- additional info
- Publisher Copyright: © The Authors 2025.
- id
- 41d5f214-a885-4997-8473-d0c2514c4f42
- date added to LUP
- 2025-04-09 15:47:42
- date last changed
- 2025-04-09 15:48:22
@article{41d5f214-a885-4997-8473-d0c2514c4f42,
abstract = {{<p>We report on the discovery and spectroscopic confirmation of TOI-2458 b, a transiting mini-Neptune around an F-type star leaving the main-sequence with a mass of M<sub>∗</sub> = 1.05 ± 0.03 M<sub>⊙</sub>, a radius of R<sub>∗</sub> = 1.31 ± 0.03 R<sub>⊙</sub>, an effective temperature of T<sub>eff</sub> = 6005 ± 50 K, and a metallicity of 0.10 ± 0.05 dex. By combining TESS photometry with high-resolution spectra acquired with the HARPS spectrograph, we found that the transiting planet has an orbital period of 3.74 days, a mass of M<sub>p</sub> = 13.31 ± 0.99 M<sub>⊕</sub> and a radius of R<sub>p</sub> = 2.83 ± 0.20 R<sub>⊕</sub>. The host star TOI-2458 shows a short activity cycle of ∼54 days revealed in the HARPS S-index and Ha times series. We took the opportunity to investigate other F stars showing activity cycle periods comparable to that of TOI-2458 and found that they have shorter rotation periods than would be expected based on the gyrochronology predictions. In addition, we determined TOI-2458's stellar inclination angle to be i<sub>∗</sub> = 10.6<sub>10.6</sub><sup>+13.3</sup> degrees. We discuss that both phenomena (fast stellar rotation and planet orbit inclination) could be explained by in situ formation of a hot Jupiter interior to TOI-2458 b. It is plausible that this hot Jupiter was recently engulfed by the star. Analysis of HARPS spectra has identified the presence of another planet with a period of P = 16.55 ± 0.06 days and a minimum mass of M<sub>p</sub> sin i = 10.22 ± 1.90 M<sub>⊕</sub>.</p>}},
author = {{Šubjak, Ján and Gandolfi, Davide and Goffo, Elisa and Rapetti, David and Jankowski, Dawid and Mizuki, Toshiyuki and Dai, Fei and Serrano, Luisa M. and Wilson, Thomas G. and Goåºdziewski, Krzysztof and Nowak, Grzegorz and Jenkins, Jon M. and Twicken, Joseph D. and Winn, Joshua N. and Bieryla, Allyson and Ciardi, David R. and Cochran, William D. and Collins, Karen A. and Deeg, Hans J. and García, Rafael A. and Guenther, Eike W. and Hatzes, Artie P. and Kabáth, Petr and Korth, Judith and Latham, David W. and Livingston, John H. and Lund, Michael B. and Mathur, Savita and Narita, Norio and Orell-Miquel, Jaume and Pallé, Enric and Persson, Carina M. and Redfield, Seth and Schwarz, Richard P. and Watanabe, David and Ziegler, Carl}},
issn = {{0004-6361}},
keywords = {{Planetary systems; Planets and satellites: dynamical evolution and stability; Planets and satellites: formation; Techniques: photometric; Techniques: radial velocities; Techniques: spectroscopic}},
language = {{eng}},
month = {{01}},
publisher = {{EDP Sciences}},
series = {{Astronomy and Astrophysics}},
title = {{TOI-2458 b : A mini-Neptune consistent with in situ hot Jupiter formation}},
url = {{http://dx.doi.org/10.1051/0004-6361/202451057}},
doi = {{10.1051/0004-6361/202451057}},
volume = {{693}},
year = {{2025}},
}