Volume 619, November 2018
|Number of page(s)||18|
|Section||Planets and planetary systems|
|Published online||30 October 2018|
Diagnosing aerosols in extrasolar giant planets with cross-correlation function of water bands
Observatoire astronomique de l'Université de Genève, Université de Genève,
51 chemin des Maillettes,
2 Dipartimento di Fisica e Astronomia “Galileo Galilei”, Université di Padova, Vicolo dell'Osservatorio 3, Padova 35122, Italy
3 Department of Physics, University of Warwick, Coventry CV4 7AL, UK
4 Center for Space and Habitability, University of Bern, Sidlerstrasse 5, 3012, Bern, Switzerland
5 INAF – Osservatorio Astronomico di Padova, vicolo dell’Osservatorio 5, 35122, Padova, Italy
Accepted: 16 July 2018
Transmission spectroscopy with ground-based, high-resolution instruments provides key insight into the composition of exoplanetary atmospheres. Molecules such as water and carbon monoxide have been unambiguously identified in hot gas giants through cross-correlation techniques. A maximum in the cross-correlation function (CCF) is found when the molecular absorption lines in a binary mask or model template match those contained in the planet. Here, we demonstrate how the CCF method can be used to diagnose broadband spectroscopic features such as scattering by aerosols in high-resolution transit spectra. The idea consists in exploiting the presence of multiple water bands from the optical to the near-infrared. We have produced a set of models of a typical hot Jupiter spanning various conditions of temperature and aerosol coverage. We demonstrate that comparing the CCFs of individual water bands for the models constrains the presence and the properties of the aerosol layers. The contrast difference between the CCFs of two bands can reach ~100 ppm, which could be readily detectable with current or upcoming high-resolution stabilized spectrographs spanning a wide spectral range, such as ESPRESSO, CARMENES, HARPS-N+GIANO, HARPS+NIRPS, SPIRou, or CRIRES+.
Key words: planets and satellites: atmospheres / planets and satellites: composition / techniques: spectroscopic
© ESO 2018
Current usage metrics show cumulative count of Article Views (full-text article views including HTML views, PDF and ePub downloads, according to the available data) and Abstracts Views on Vision4Press platform.
Data correspond to usage on the plateform after 2015. The current usage metrics is available 48-96 hours after online publication and is updated daily on week days.
Initial download of the metrics may take a while.