Diagnosing aerosols in extrasolar giant planets with cross-correlation function of water bands

Pino, Lorenzo; Ehrenreich, David; Allart, Romain; Lovis, Christophe; Brogi, Matteo; Malik, Matej; Nascimbeni, Valerio; Pepe, Francesco; Piotto, Giampaolo (2018). Diagnosing aerosols in extrasolar giant planets with cross-correlation function of water bands. Astronomy and astrophysics, 619, A3. EDP Sciences 10.1051/0004-6361/201832986

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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+.

Item Type:

Journal Article (Original Article)


10 Strategic Research Centers > Center for Space and Habitability (CSH)
08 Faculty of Science > Physics Institute > Space Research and Planetary Sciences
08 Faculty of Science > Physics Institute
08 Faculty of Science > Physics Institute > NCCR PlanetS

UniBE Contributor:

Malik, Matej


500 Science > 520 Astronomy
500 Science
500 Science > 530 Physics




EDP Sciences




Danielle Zemp

Date Deposited:

03 Jun 2019 13:24

Last Modified:

22 Oct 2019 19:06

Publisher DOI:






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