Evidence for Morning-to-Evening Limb Asymmetry on the Cool Low-Density Exoplanet WASP-107b

Fuente: arXiv
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Hauptverfasser: Murphy, Matthew M., Beatty, Thomas G., Schlawin, Everett, Bell, Taylor J., Line, Michael R., Greene, Thomas P., Parmentier, Vivien, Rauscher, Emily, Welbanks, Luis, Fortney, Jonathan J., Rieke, Marcia
Format: Preprint
Veröffentlicht: 2024
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author Murphy, Matthew M.
Beatty, Thomas G.
Schlawin, Everett
Bell, Taylor J.
Line, Michael R.
Greene, Thomas P.
Parmentier, Vivien
Rauscher, Emily
Welbanks, Luis
Fortney, Jonathan J.
Rieke, Marcia
author_facet Murphy, Matthew M.
Beatty, Thomas G.
Schlawin, Everett
Bell, Taylor J.
Line, Michael R.
Greene, Thomas P.
Parmentier, Vivien
Rauscher, Emily
Welbanks, Luis
Fortney, Jonathan J.
Rieke, Marcia
contents The atmospheric properties of hot exoplanets are expected to be different between the morning and the evening limb due to global atmospheric circulation. Ground-based observations at high spectral resolution have detected this limb asymmetry in several ultra-hot (>2000 K) exoplanets, but the prevalence of the phenomenon in the broader exoplanetary population remains unexplored. Here we use JWST/NIRCam transmission spectra between 2.5 and 4.0 $μ$m to find evidence of limb asymmetry on exoplanet WASP-107 b. With its equilibrium temperature of 770 K and low density of 0.126 gm c$^{-3}$, WASP-107 b probes a very different regime compared to ultra-hot giant planets and was not expected to exhibit substantial spatial heterogeneity according to atmospheric models. We infer instead a morning-evening temperature difference on the order of 100 K with a hotter evening limb. Further observations on other cooler exoplanets are needed to determine whether WASP-107 b is an outlier or the models underestimate the presence of limb asymmetry in exoplanets.
format Preprint
id arxiv_https___arxiv_org_abs_2406_09863
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Evidence for Morning-to-Evening Limb Asymmetry on the Cool Low-Density Exoplanet WASP-107b
Murphy, Matthew M.
Beatty, Thomas G.
Schlawin, Everett
Bell, Taylor J.
Line, Michael R.
Greene, Thomas P.
Parmentier, Vivien
Rauscher, Emily
Welbanks, Luis
Fortney, Jonathan J.
Rieke, Marcia
Earth and Planetary Astrophysics
Instrumentation and Methods for Astrophysics
The atmospheric properties of hot exoplanets are expected to be different between the morning and the evening limb due to global atmospheric circulation. Ground-based observations at high spectral resolution have detected this limb asymmetry in several ultra-hot (>2000 K) exoplanets, but the prevalence of the phenomenon in the broader exoplanetary population remains unexplored. Here we use JWST/NIRCam transmission spectra between 2.5 and 4.0 $μ$m to find evidence of limb asymmetry on exoplanet WASP-107 b. With its equilibrium temperature of 770 K and low density of 0.126 gm c$^{-3}$, WASP-107 b probes a very different regime compared to ultra-hot giant planets and was not expected to exhibit substantial spatial heterogeneity according to atmospheric models. We infer instead a morning-evening temperature difference on the order of 100 K with a hotter evening limb. Further observations on other cooler exoplanets are needed to determine whether WASP-107 b is an outlier or the models underestimate the presence of limb asymmetry in exoplanets.
title Evidence for Morning-to-Evening Limb Asymmetry on the Cool Low-Density Exoplanet WASP-107b
topic Earth and Planetary Astrophysics
Instrumentation and Methods for Astrophysics
url https://arxiv.org/abs/2406.09863