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
Planets and satellites: atmospheres
Techniques: spectroscopic
Stars: individual: HD 235088
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
Instituto de Astrofísica de Canarias
Universidad de la Laguna
A. Peláez-Torres
Instituto de Astrofísica de Canarias
Universidad de la Laguna
Enric Palle
Instituto de Astrofísica de Canarias
Universidad de la Laguna
E. Esparza-Borges
Instituto de Astrofísica de Canarias
Universidad de la Laguna
J. Sanz-Forcada
European Space Astronomy Centre (ESAC)
H. M. Tabernero
Centro de Astrobiologia (CAB)
L. Nortmann
Georg-August-Universität Göttingen
E. Nagel
Georg-August-Universität Göttingen
H. Parviainen
Universidad de la Laguna
Instituto de Astrofísica de Canarias
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
Chalmers, Rymd-, geo- och miljövetenskap, Astronomi och plasmafysik
Instituto de Astrofísica de Canarias
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
Ludwig-Maximilians-Universität München (LMU)
Landessternwarte Heidelberg-Königstuhl
D. Montes
IPARCOS-UCM (Instituto de Física de Partículas y del Cosmos)
Norio Narita
National Institutes of Natural Sciences
Instituto de Astrofísica de Canarias
University of Tokyo
A. Reiners
Georg-August-Universität Göttingen
I. Ribas
Consejo Superior de Investigaciones Científicas (CSIC)
Centre Tecnològic de Telecomunicacions de Catalunya (CTTC)
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