A He I upper atmosphere around the warm Neptune GJ 3470 b

High resolution transit spectroscopy has proven to be a reliable technique for the characterization of the chemical composition of exoplanet atmospheres. Taking advantage of the broad spectral coverage of the CARMENES spectrograph, we initiated a survey aimed at characterizing a broad range of plane...

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Detalhes bibliográficos
Autores: Pallé, Enric, Nortmann, L., Casasayas-Barris, N., Lampón, M., López-Puertas, Manuel, Caballero, J. A., Sanz-Forcada, J., Lara, Luisa María, Nagel, Evangelos, Yan, F., Alonso-Floriano, F. Javier, Amado, Pedro J., Chen, G., Cifuentes, C., Cortés-Contreras, M., Czesla, S., Molaverdikhani, K., Montes, David, Passegger, V.M., Quirrenbach, Andreas, Reiners, Ansgar, Ribas, Ignasi, Sánchez-López, A., Schweitzer, Andreas, Stangret, M., Zapatero Osorio, María Rosa, Zechmeister, Mathias
Formato: artículo
Estado:Versión publicada
Fecha de publicación:2020
País:España
Recursos:Consejo Superior de Investigaciones Científicas (CSIC)
Repositorio:DIGITAL.CSIC. Repositorio Institucional del CSIC
OAI Identifier:oai:digital.csic.es:10261/216416
Acesso em linha:http://hdl.handle.net/10261/216416
Access Level:acceso abierto
Palavra-chave:Planetary systems
Planets and satellites
Atmospheres
Planet-star interactions
Planets and satellites: general
Planets and satellites: individual
GJ 3470b
Descrição
Resumo:High resolution transit spectroscopy has proven to be a reliable technique for the characterization of the chemical composition of exoplanet atmospheres. Taking advantage of the broad spectral coverage of the CARMENES spectrograph, we initiated a survey aimed at characterizing a broad range of planetary systems. Here, we report our observations of three transits of GJ 3470 b with CARMENES in search of He (2(3)S) absorption. On one of the nights, the He & x202f;Iregion was heavily contaminated by OH(-)telluric emission and, thus, it was not useful for our purposes. The remaining two nights had a very different signal-to-noise ratio (S/N) due to weather. They both indicate the presence of He (2(3)S) absorption in the transmission spectrum of GJ 3470 b, although a statistically valid detection can only be claimed for the night with higher S/N. For that night, we retrieved a 1.5 +/- 0.3% absorption depth, translating into aR(p)(lambda)/R-p= 1.15 +/- 0.14 at this wavelength. Spectro-photometric light curves for this same night also indicate the presence of extra absorption during the planetary transit with a consistent absorption depth. The He (2(3)S) absorption is modeled in detail using a radiative transfer code, and the results of our modeling efforts are compared to the observations. We find that the mass-loss rate,& x1e40;, is confined to a range of 3 x 10(10)g s(-1)forT= 6000 K to 10 x 10(10)g s(-1)forT= 9000 K. We discuss the physical mechanisms and implications of the He & x202f;Idetection in GJ 3470 b and put it in context as compared to similar detections and non-detections in other Neptune-size planets. We also present improved stellar and planetary parameter determinations based on our visible and near-infrared observations.

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