| Autor: |
Krishna Kanumalla, Michael R. Line, Megan Weiner Mansfield, Luis Welbanks, Peter C. B. Smith, Jacob L. Bean, Lorenzo Pino, Matteo Brogi, Vatsal Panwar |
| Jazyk: |
angličtina |
| Rok vydání: |
2024 |
| Předmět: |
|
| Zdroj: |
The Astronomical Journal, Vol 168, Iss 5, p 201 (2024) |
| Druh dokumentu: |
article |
| ISSN: |
1538-3881 |
| DOI: |
10.3847/1538-3881/ad72f3 |
| Popis: |
High-resolution spectroscopy of exoplanet atmospheres provides insights into their composition and dynamics from the resolved line shape and depth of thousands of spectral lines. WASP-127 b is an extremely inflated sub-Saturn ( R _p = 1.311 R _Jup , M _p = 0.16 M _Jup ) with previously reported detections of H _2 O and CO _2 . However, the seeming absence of the primary carbon reservoir expected at WASP-127 b temperatures ( T _eq ∼1400 K) from chemical equilibrium, CO, posed a mystery. In this manuscript, we present the analysis of high-resolution observations of WASP-127 b with the Immersion Grating Infrared Spectrometer on Gemini South. We confirm the presence of H _2 O (8.67 σ ) and report the detection of CO (4.34 σ ). Additionally, we conduct a suite of Bayesian retrieval analyses covering a hierarchy of model complexity and self-consistency. When freely fitting for the molecular gas volume mixing ratios, we obtain super-solar metal enrichment for H _2 O abundance of log _10 X ${}_{{{\rm{H}}}_{2}{\rm{O}}}$ = −1.23 ${}_{-0.49}^{+0.29}$ and a lower limit on the CO abundance of log _10 X _CO ≥–2.20 at 2 σ confidence. We also report tentative evidence of photochemistry in WASP-127 b based upon the indicative depletion of H _2 S. This is also supported by the data preferring models with photochemistry over free-chemistry and thermochemistry. The overall analysis implies a super-solar (∼39× Solar; [M/H] = ${1.59}_{-0.30}^{+0.30}$ ) metallicity for the atmosphere of WASP-127 b and an upper limit on its atmospheric C/O ratio as < 0.68. |
| Databáze: |
Directory of Open Access Journals |
| Externí odkaz: |
|
