Confirmation of an He I evaporating atmosphere around the 650-Myr-old sub-Neptune HD 235088 b (TOI-1430 b) with CARMENES
Artikel i vetenskaplig tidskrift, 2023
HD 235088 (TOI-1430) is a young star known to host a sub-Neptune-sized planet candidate. We validated the planetary nature of HD 235088 b with multiband photometry, refined its planetary parameters, and obtained a new age estimate of the host star, placing it at 600- 800 Myr. Previous spectroscopic observations of a single transit detected an excess absorption of He I coincident in time with the planet candidate transit. Here, we confirm the presence of He I in the atmosphere of HD 235088 b with one transit observed with CARMENES. We also detected hints of variability in the strength of the helium signal, with an absorption of -0.91 ± 0.11%, which is slightly deeper (2γ) than the previous measurement. Furthermore, we simulated the He I signal with a spherically symmetric 1D hydrodynamic model, finding that the upper atmosphere of HD 235088 b escapes hydrodynamically with a significant mass loss rate of (1.5-5) × 1010 g s-1 in a relatively cold outflow, with T = 3125 ±375 K, in the photon-limited escape regime. HD 235088 b (Rp = 2.045 ± 0.075 R⊕) is the smallest planet found to date with a solid atmospheric detection - not just of He I but any other atom or molecule. This positions it a benchmark planet for further analyses of evolving young sub-Neptune atmospheres.
Planets and satellites: individual: HD 235088 b
Stars: individual: HD 235088
Planets and satellites: atmospheres
Techniques: spectroscopic
Techniques: photometric
Författare
J. Orell-Miquel
Universidad de la Laguna
Instituto de Astrofísica de Canarias
M. Lampon
Consejo Superior de Investigaciones Científicas (CSIC)
M. López-Puertas
Consejo Superior de Investigaciones Científicas (CSIC)
M. Mallorquín
Universidad de la Laguna
Instituto de Astrofísica de Canarias
F. Murgas
Universidad de la Laguna
Instituto de Astrofísica de Canarias
A. Peláez-Torres
Instituto de Astrofísica de Canarias
Universidad de la Laguna
Enric Palle
Universidad de la Laguna
Instituto de Astrofísica de Canarias
E. Esparza-Borges
Instituto de Astrofísica de Canarias
Universidad de la Laguna
J. Sanz-Forcada
Europeiska rymdorganisationen (ESA)
H. M. Tabernero
Centro de Astrobiologia (CAB)
L. Nortmann
Georg-August-Universität Göttingen
E. Nagel
Georg-August-Universität Göttingen
H. Parviainen
Instituto de Astrofísica de Canarias
Universidad de la Laguna
M. Zapatero-Osorio
Centro de Astrobiologia (CAB)
J. A. Caballero
Centro de Astrobiologia (CAB)
S. Czesla
Thüringer Landessternwarte Tautenburg
C. Cifuentes
Centro de Astrobiologia (CAB)
Giuseppe Morello
Instituto de Astrofísica de Canarias
Chalmers, Rymd-, geo- och miljövetenskap, Astronomi och plasmafysik
A. Quirrenbach
Landessternwarte Heidelberg-Königstuhl
P. J. Amado
Consejo Superior de Investigaciones Científicas (CSIC)
A. Fernández-Martín
Calar Alto Astronomical Observatory
A. Fukui
National Institutes of Natural Sciences
Instituto de Astrofísica de Canarias
T. Henning
Max-Planck-Gesellschaft
Kiyoe Kawauchi
University of Tokyo
Jerome P. De Leon
University of Tokyo
K. Molaverdikhani
Landessternwarte Heidelberg-Königstuhl
Ludwig-Maximilians-Universität München (LMU)
D. Montes
Universidad Complutense de Madrid
Norio Narita
Instituto de Astrofísica de Canarias
University of Tokyo
National Institutes of Natural Sciences
A. Reiners
Georg-August-Universität Göttingen
I. Ribas
Centre Tecnològic de Telecomunicacions de Catalunya (CTTC)
Consejo Superior de Investigaciones Científicas (CSIC)
A. Sánchez-López
Consejo Superior de Investigaciones Científicas (CSIC)
A. Schweitzer
Universität Hamburg
M. Stangret
Istituto nazionale di astrofisica (INAF)
F. Yan
University of Science and Technology of China
Astronomy and Astrophysics
0004-6361 (ISSN) 1432-0746 (eISSN)
Vol. 677 A56Ämneskategorier (SSIF 2011)
Astronomi, astrofysik och kosmologi
DOI
10.1051/0004-6361/202346445