Search for an exosphere in sodium and calcium in the transmission spectrum of exoplanet 55 Cancri e

A. R. Ridden-Harper, I. A. G. Snellen, C. U. Keller +7

[Abridged] The aim of this work is to search for an absorption signal from exospheric sodium (Na) and singly ionized calcium (Ca${}^{+}$) in the optical transmission spectrum of the ho…