Exoplanetology: Exoplanets & Exomoons

The JWST Weather Report From the Isolated Exoplanet Analog SIMP 0136+0933: Pressure-Dependent Variability Driven by Multiple Mechanisms

By Keith Cowing

Status Report

astro-ph.EP

November 26, 2024

Filed under astro-ph.EP, astronomy, atmosphere, brown dwarf, climate, Clouds, exoplanet, gas giant, Interstellar, Isolated planetary-mass object, JWST, Rogue Planet, SIMP J013656.5+093347.3, Spectroscopy

The JWST Weather Report From the Isolated Exoplanet Analog SIMP 0136+0933: Pressure-Dependent Variability Driven by Multiple Mechanisms — Top panel: Final flux-calibrated NIRSpec/Prism (blue) and MIRI/LRS (red) spectra of SIMP 0136+0933, compared to the spectrum presented in Vos et al. (2023) (black) and error (shaded in grey). For the NIRSpec and MIRI spectra, each spectrum is plotted individually. Notable absorption features are indicated by horizontal black lines and their labels. For each instrument, we plot each spectrum individually, so the observed spread is a result of both noise and intrinsic variability. Bottom panel: Minimum spectrum subtracted from the maximum spectrum. The maximum and minimum spectra were identified using the 4.5 − 5.1 µm light curve (Figure 4). — astro-ph.EP

Isolated planetary-mass objects share their mass range with planets but do not orbit a star. They lack the necessary mass to support fusion in their cores and thermally radiate their heat from formation as they cool, primarily at infrared wavelengths.

Many isolated planetary-mass objects show variations in their infrared brightness consistent with non-uniform atmospheric features modulated by their rotation. SIMP J013656.5+093347.3 is a rapidly rotating isolated planetary-mass object, and previous infrared monitoring suggests complex atmospheric features rotating in and out of view.

The physical nature of these features is not well understood, with clouds, temperature variations, thermochemical instabilities, and infrared-emitting aurora all proposed as contributing mechanisms. Here we report JWST time-resolved low-resolution spectroscopy from 0.8 – 11 micron of SIMP J013656.5+093347.3 which supports the presence of three specific features in the atmosphere: clouds, hot spots, and changing carbon chemistry.

We show that no single mechanism can explain the variations in the time-resolved spectra. When combined with previous studies of this object indicating patchy clouds and aurorae, these measurements reveal the rich complexity of the atmosphere of SIMP J013656.5+093347.3.

Gas giant planets in the solar system, specifically Jupiter and Saturn, also have multiple cloud layers and high-altitude hot spots, suggesting these phenomena are also present in worlds both within and beyond our solar-system.

Allison M. McCarthy, Johanna M. Vos, Philip S. Muirhead, Beth A. Biller, Caroline V. Morley, Jacqueline Faherty, Ben Burningham, Emily Calamari, Nicolas B. Cowan, Kelle L. Cruz, Eileen Gonzales, Mary Anne Limbach, Pengyu Liu, Evert Nasedkin, Genaro Suarez, Xianyu Tan, Cian O’Toole, Channon Visscher, Niall Whiteford, Yifan Zhou

Comments: Accepted to ApJ Letters
Subjects: Earth and Planetary Astrophysics (astro-ph.EP); Solar and Stellar Astrophysics (astro-ph.SR)
Cite as: arXiv:2411.16577 [astro-ph.EP] (or arXiv:2411.16577v1 [astro-ph.EP] for this version)
https://doi.org/10.48550/arXiv.2411.16577
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Submission history
From: Allison McCarthy
[v1] Mon, 25 Nov 2024 17:06:16 UTC (14,191 KB)
https://arxiv.org/abs/2411.16577
Astrobiology,

Keith Cowing

Explorers Club Fellow, ex-NASA Space Station Payload manager/space biologist, Away Teams, Journalist, Lapsed climber, Synaesthete, Na’Vi-Jedi-Freman-Buddhist-mix, ASL, Devon Island and Everest Base Camp veteran, (he/him) 🖖🏻

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