Physics and Astronomy Faculty Publications and Presentations
Document Type
Article
Publication Date
3-2025
Abstract
One of the most prolific methods of studying exoplanet atmospheres is transmission spectroscopy, which measures the difference between the depth of an exoplanet's transit signal at various wavelengths and attempts to correlate the depth changes to potential features in the exoplanet's atmosphere. Here we present reconnaissance observations of 21 exoplanet atmospheres measured with the Exoplanet Transmission Spectroscopy Imager (ETSI), a recently deployed spectrophotometer on the McDonald Observatory Otto Struve 2.1 m telescope. ETSI measurements are mostly free of systematics through the use of a novel observing technique called common-path multiband imaging (CMI), which has been shown to achieve photometric color precision on par with space-based observations (300 ppm or 0.03%). This work also describes the various statistical tests performed on the data to evaluate the efficacy of the CMI method and the ETSI instrument in combination. We find that none of the eight comparisons of exoplanet atmospheres measured with ETSI and other observatories (including the Hubble Space Telescope) provide evidence that the spectra are statistically dissimilar. These results suggest that ETSI can provide initial transmission spectroscopy observations for a fraction of the observational and monetary overhead previously required to detect an exoplanet's atmosphere. Ultimately these reconnaissance observations increase the number of planets with transmission spectroscopy measurements by ~10% and provide an immediate prioritization of 21 exoplanets for future follow-up with more precious observatories, such as the James Webb Space Telescope. The reconnaissance spectra are available through the Filtergraph visualization portal at the URL https://filtergraph.com/etsi/.
Recommended Citation
Oelkers, Ryan J., Luke M. Schmidt, Erika Cook, Mary Anne Limbach, D. L. DePoy, J. L. Marshall, Jimmy Ardoin et al. "Ground-based reconnaissance observations of 21 exoplanet atmospheres with the exoplanet transmission spectroscopy imager." The Astronomical Journal 169, no. 3 (2025): 134. https://doi.org/10.3847/1538-3881/ada557
Publication Title
The Astronomical Journal
DOI
10.3847/1538-3881/ada557
Comments
© 2025. The Author(s). Published by the American Astronomical Society. Content from this work may be used under the terms of the Creative Commons Attribution 4.0 licence. Any further distribution of this work must maintain attribution to the author(s) and the title of the work, journal citation and DOI.