A Non-Detection of Iron in the First High-Resolution Emission Study of the Lava Planet 55 Cnc e

TL;DR

This study uses high-resolution spectra to set upper limits on the atmospheric pressure of the lava planet 55 Cnc e, suggesting it likely has a very thin or absent mineral atmosphere below 100 mbar.

Contribution

It provides the first high-resolution emission study of 55 Cnc e and constrains its atmospheric pressure, supporting crustal evaporation models.

Findings

Atmospheric pressure of 55 Cnc e is below 100 mbar.

Results are consistent with crustal evaporation models.

No significant atmospheric detection was made.

Abstract

Close-in lava planets represent an extreme example of terrestrial worlds, but their high temperatures may allow us to probe a diversity of crustal compositions. The brightest and most well-studied of these objects is 55 Cancri e, a nearby super-Earth with a remarkably short 17-hour orbit. However, despite numerous studies, debate remains about the existence and composition of its atmosphere. We present upper limits on the atmospheric pressure of 55 Cnc e derived from high-resolution time-series spectra taken with Gemini-N/MAROON-X. Our results are consistent with current crustal evaporation models for this planet which predict a thin $\sim$ 100 mbar atmosphere. We conclude that, if a mineral atmosphere is present on 55 Cnc e, the atmospheric pressure is below 100 mbar.