A Comprehensive Analysis of WASP-17b's Transmission Spectrum from Space-Based Observations
L. Alderson, H. R. Wakeford, R. J. MacDonald, N. K. Lewis, E. M. May,, D. Grant, D. K. Sing, K. B. Stevenson, J. Fowler, J. Goyal, N. E. Batalha, T., Kataria

TL;DR
This study presents a detailed transmission spectrum of exoplanet WASP-17b from space-based observations, detecting water and carbon dioxide absorption features, and highlights the importance of multi-method retrievals for atmospheric characterization.
Contribution
It provides the first comprehensive 0.3-5 μm transmission spectrum of WASP-17b using multiple space telescopes and advanced analysis techniques, revealing key atmospheric constituents and retrieval challenges.
Findings
Detection of H$_2$O at >7σ
Evidence of CO$_2$ at >3σ
No detection of Na and K absorption
Abstract
Due to its 1770 K equilibrium temperature, WASP-17b, a 1.99 , 0.486 exoplanet, sits at the critical juncture between hot and ultra-hot Jupiters. We present its 0.3-5 transmission spectrum, with newly obtained with Hubble Space Telescope (HST) Wide Field Camera 3 (WFC3) measurements, and, taking advantage of improved analysis techniques, reanalysed HST Space Telescope Imaging Spectrograph (STIS) and Spitzer Space Telescope Infrared Array Camera (IRAC) observations. We achieve a median precision of 132 ppm, with a mean of 272 ppm across the whole spectrum. We additionally make use of Transiting Exoplanet Survey Satellite (TESS) and ground-based transit observations to refine the orbital period of WASP-17b. To interpret the observed atmosphere, we make use of free and equilibrium chemistry retrievals using the POSEIDON and ATMO retrieval codes…
Peer Reviews
No public reviews on file for this paper yet. If you reviewed it on a platform where reviews are public (OpenReview, ICLR, NeurIPS, ICML), you can paste yours below so the community can read it here.
Videos
No videos yet. Explain this paper in a talk, walkthrough, or lecture? Add one.
