Tentative Evidence for Water Vapor in the Atmosphere of the Neptune-sized Exoplanet HD 106315c
Article
Article Title | Tentative Evidence for Water Vapor in the Atmosphere of the Neptune-sized Exoplanet HD 106315c |
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ERA Journal ID | 1057 |
Article Category | Article |
Authors | Kreidberg, Laura, Molliere, Paul, Crossfield, Ian J. M., Thorngren, Daniel P., Kawashima, Yui Kawashima, Morley, Caroline V., Benneke, Björn, Mikal-Evans, Thomas, Berardo, David, Kosiarek, Molly R., Gorjian, Varoujan, Ciardi, David R., Christiansen, Jessie L., Dragomir, Diana, Dressing, Courtney D., Fortney, Jonathan J., Fulton, Benjamin J., Greene, Thomas P., Hardegree-Ullman, Kevin K, Howard, Andrew W., Howell, Steve B., Isaacson, Howard, Krick, Jessica E. K, Livingston, John H., Lothringer, Joshua D., Morales, Farisa Y., Petigura, Erik A., Rodriguez, Joseph E., Schlieder, Joshua E. and Weiss, Lauren M. |
Journal Title | The Astrophysical Journal: an international review of astronomy and astronomical physics |
Journal Citation | 164 (4) |
Article Number | 124 |
Number of Pages | 15 |
Year | 2022 |
Publisher | IOP Publishing |
Place of Publication | United States |
ISSN | 0004-637X |
1538-4357 | |
Digital Object Identifier (DOI) | https://doi.org/10.3847/1538-3881/ac85be |
Web Address (URL) | https://iopscience.iop.org/article/10.3847/1538-3881/ac85be |
Abstract | We present a transmission spectrum for the Neptune-sized exoplanet HD 106315c from optical to infrared wavelengths based on transit observations from the Hubble Space Telescope/Wide Field Camera 3, K2, and Spitzer. The spectrum shows tentative evidence for a water absorption feature in the 1.1–1.7 μm wavelength range with a small amplitude of 30 ppm (corresponding to just 0.8 ± 0.04 atmospheric scale heights). Based on an atmospheric retrieval analysis, the presence of water vapor is tentatively favored with a Bayes factor of 1.7–2.6 (depending on prior assumptions). The spectrum is most consistent with either an enhanced metallicity or high-altitude condensates, or both. Cloud-free solar composition atmospheres are ruled out at >5σ confidence. We compare the spectrum to grids of cloudy and hazy forward models and find that the spectrum is fit well by models with moderate cloud lofting or haze formation efficiency over a wide range of metallicities (1–100× solar). We combine the constraints on the envelope composition with an interior structure model and estimate that the core mass fraction is ≳0.3. With a bulk composition reminiscent of that of Neptune and an orbital distance of 0.15 au, HD 106315c hints that planets may form out of broadly similar material and arrive at vastly different orbits later in their evolution. |
Keywords | Atmospheric clouds; Neptune; Water vapor; Exoplanet |
ANZSRC Field of Research 2020 | 5101. Astronomical sciences |
Byline Affiliations | Max Planck Institute for Astronomy, Germany |
Center for Astrophysics Harvard and Smithsonian, United States | |
University of Kansas, United States | |
University of Montreal, Canada | |
RIKEN, Japan | |
University of Texas at Austin, United States | |
Massachusetts Institute of Technology, United States | |
University of California, United States | |
California Institute of Technology (Caltech), United States | |
NASA Exoplanet Science Institute, United States | |
Infrared Processing and Analysis Center (IPAC), United States | |
University of New Mexico, United States | |
University of California Berkeley, United States | |
NASA Ames Research Center, United States | |
Centre for Astrophysics | |
University of Tokyo, Japan | |
Johns Hopkins University, United States | |
NASA Goddard Space Flight Center, United States | |
University of Hawaii, United States |
https://research.usq.edu.au/item/z0243/tentative-evidence-for-water-vapor-in-the-atmosphere-of-the-neptune-sized-exoplanet-hd-106315c
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