A tentative detection of He I in the atmosphere of GJ 1214b
| Autor: | Orell-Miquel, J., Murgas, F., Pallé, E., Lampón, M., López-Puertas, M., Sanz-Forcada, J., Nagel, E., Kaminski, A., Casasayas-Barris, N., Nortmann, L., Luque, R., Molaverdikhani, K., Sedaghati, E., Caballero, J. A., Amado, P. J., Bergond, G., Czesla, S., Hatzes, A. P., Henning, Th., Khalafinejad, S., Montes, D., Morello, G., Quirrenbach, A., Reiners, A., Ribas, I., Sánchez-López, A., Schweitzer, A., Stangret, M., Yan, F., Osorio, M. R. Zapatero |
|---|---|
| Rok vydání: | 2022 |
| Předmět: | |
| Zdroj: | A&A 659, A55 (2022) |
| Druh dokumentu: | Working Paper |
| DOI: | 10.1051/0004-6361/202142455 |
| Popis: | The $\ion{He}{I}$ 10833\,$\AA$ triplet is a powerful tool for characterising the upper atmosphere of exoplanets and tracing possible mass loss. Here, we analysed one transit of GJ\,1214\,b observed with the CARMENES high-resolution spectrograph to study its atmosphere via transmission spectroscopy around the $\ion{He}{I}$ triplet. Although previous studies using lower resolution instruments have reported non-detections of $\ion{He}{I}$ in the atmosphere of GJ\,1214\,b, we report here the first potential detection. We reconcile the conflicting results arguing that previous transit observations did not present good opportunities for the detection of $\ion{He}{I}$, due to telluric H$_2$O absorption and OH emission contamination.We simulated those earlier observations, and show evidence that the planetary signal was contaminated. From our single non-telluric-contaminated transit, we determined an excess absorption of 2.10$^{+0.45}_{-0.50}$\,\% (4.6\,$\sigma$) with a full width at half maximum (FWHM) of 1.30$^{+0.30}_{-0.25}$\,\AA. The detection of \ion{He}{I} is statistically significant at the 4.6\,$\sigma$ level, but repeatability of the detection could not be confirmed due to the availability of only one transit. By applying a hydrodynamical model and assuming an H/He composition of 98/2, we found that GJ\,1214\,b would undergo hydrodynamic escape in the photon-limited regime, losing its primary atmosphere with a mass-loss rate of (1.5--18)\,$\times$\,10$^{10}$\,g\,s$^{-1}$ and an outflow temperature in the range of 2900--4400\,K. Our $\ion{He}{I}$ excess absorption is the first tentative detection of a chemical species in the atmosphere of this benchmark sub-Neptune planet. Comment: Accepted for publication in A&A. 12 pages, 7 figures |
| Databáze: | arXiv |
| Externí odkaz: |
|