Keck/NIRSPEC Studies of He I in the Atmospheres of Two Inflated Hot Gas Giants Orbiting K Dwarfs: WASP-52b and WASP-177b
Article
Article Title | Keck/NIRSPEC Studies of He I in the Atmospheres of Two Inflated Hot Gas Giants Orbiting K Dwarfs: WASP-52b and WASP-177b |
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ERA Journal ID | 1048 |
Article Category | Article |
Authors | Kirk, James (Author), Dos Santos, Leonardo A. (Author), Lopez-Morales, Mercedes (Author), Alam, Munazza K. (Author), Oklopcic, Antonija (Author), MacLeod, Morgan (Author), Zeng, Li (Author) and Zhou, George (Author) |
Journal Title | The Astronomical Journal |
Journal Citation | 164 (1), pp. 1-14 |
Article Number | 24 |
Number of Pages | 14 |
Year | 2022 |
Publisher | IOP Publishing |
Place of Publication | United States |
ISSN | 0004-6256 |
1538-3881 | |
Digital Object Identifier (DOI) | https://doi.org/10.3847/1538-3881/ac722f |
Web Address (URL) | https://iopscience.iop.org/article/10.3847/1538-3881/ac722f |
Abstract | We present the detection of neutral helium at 10833 Å in the atmosphere of WASP-52b and tentative evidence of helium in the atmosphere of the grazing WASP-177b, using high-resolution observations acquired with the NIRSPEC instrument on the Keck II telescope. We detect excess absorption by helium in WASP-52b's atmosphere of 3.44% ± 0.31% (11σ), or equivalently 66 ± 5 atmospheric scale heights. This absorption is centered on the planet's rest frame (Δv = 0.00 ± 1.19 km s-1). We model the planet's escape using a 1D Parker wind model and calculate its mass-loss rate to be ∼1.4 × 1011 g s-1, or equivalently 0.5% of its mass per gigayear. For WASP-177b, we see evidence for redshifted (Δv = 6.02 ± 1.88 km s-1) helium-like absorption of 1.28% ± 0.29% (equal to 23 ± 5 atmospheric scale heights). However, due to residual systematics in the transmission spectrum of similar amplitude, we do not interpret this as significant evidence for He absorption in the planet's atmosphere. Using a 1D Parker wind model, we set a 3σ upper limit on WASP-177b's escape rate of 7.9 × 1010 g s-1. Our results, taken together with recent literature detections, suggest the tentative relation between XUV irradiation and He i absorption amplitude may be shallower than previously suggested. Our results highlight how metastable helium can advance our understanding of atmospheric loss and its role in shaping the exoplanet population. |
Keywords | Exoplanet atmospheres; Exoplanet astronomy; Astrophysics -Earth and Planetary Astrophysics |
ANZSRC Field of Research 2020 | 510109. Stellar astronomy and planetary systems |
Institution of Origin | University of Southern Queensland |
Byline Affiliations | Center for Astrophysics Harvard and Smithsonian, United States |
Space Telescope Science Institute, United States | |
University of Amsterdam, Netherlands | |
Harvard University, United States | |
Centre for Astrophysics | |
Funding source | Australian Research Council (ARC) Grant ID DE210101893 |
https://research.usq.edu.au/item/q7qvx/keck-nirspec-studies-of-he-i-in-the-atmospheres-of-two-inflated-hot-gas-giants-orbiting-k-dwarfs-wasp-52b-and-wasp-177b
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