YunMa: Enabling Spectral Retrievals of Exoplanetary Clouds

In this paper, we present YunMa, a model which enables the study of cloud microphysics and radiative properties in exoplanetary atmospheres.

YunMa simulates the vertical distribution and sizes of cloud particles and their corresponding scattering signature in transit spectra. We validated YunMa against results from the literature.

When coupled to the TauREx 3 platform, an open Bayesian framework for spectral retrievals, YunMa enables the retrieval of the cloud properties and parameters from transit spectra of exoplanets. The sedimentation efficiency (fsed), which controls the cloud microphysics, is set as a free parameter in retrievals. We assess the retrieval performances of YunMa through 28 instances of a cloudy super-Earth’s atmosphere. This work also highlights the need for cloud radiative transfer and microphysics modelling to retrieve next-generation data of exoplanets.

Sketch of the A-M micophysical approach adopted in YunMa. Cloud particles may form when the mixing ratio of the condensable gas exceeds the saturation mixing ratio, which is derived from its saturation vapour pressure (SVP). The vertical distribution of the cloud particle sizes (VDCP) is derived from the balance between the sedimentation of the cloud particles and the atmospheric turbulent mixing.

Sushuang Ma, Yuichi Ito, Ahmed Faris Al-Refaie, Quentin Changeat, Billy Edwards, Giovanna Tinetti

Comments: 24 pages, 12 figures, submitted to ApJ
Subjects: Earth and Planetary Astrophysics (astro-ph.EP); Instrumentation and Methods for Astrophysics (astro-ph.IM)
Cite as: arXiv:2301.13708 [astro-ph.EP] (or arXiv:2301.13708v1 [astro-ph.EP] for this version)
Submission history
From: Sushuang Ma
[v1] Tue, 31 Jan 2023 15:35:37 UTC (3,387 KB)
https://arxiv.org/abs/2301.13708
Astrobiology