@article {1903.06152, archivePrefix = {arXiv}, eprint = {1903.06152}, primaryClass = {astro-ph.SR}, author = {Benjamin V. Rackham and others}, title = {Constraining Stellar Photospheres as an Essential Step for Transmission Spectroscopy of Small Exoplanets}, year = {2019}, url = {http://arxiv.org/abs/1903.06152} }