Astronomy & Telescopes

Calculating Occultation Light Curves using Wavelets: Exponential Atmospheres and the Constraints of Static Stability

By Keith Cowing

Status Report

astro-ph.EP

September 20, 2025

Filed under astro-ph.EP, astronomy, exoplanet, imaging, stellar occultation, telescope

Calculating Occultation Light Curves using Wavelets: Exponential Atmospheres and the Constraints of Static Stability — The Uranus occultation of 1995 Sept 9 from SAAO. Here we plot the immersion in normalized stellar flux vs. distance in the shadow plane, relative to half light and scaled by the atmospheric scale height. Altitude increases to the right, and, for this immersion light curve, time increases to the left. This light curve shows many of the characteristics discussed in this paper such as multiple examples of resolved spikes, some that reach higher than the unocculted flux level, and some that are observed out to 45 scale heights with wider spacing and decreased maximum flux. — astro-ph.EPThe Uranus occultation of 1995 Sept 9 from SAAO. Here we plot the immersion in normalized stellar flux vs. distance in the shadow plane, relative to half light and scaled by the atmospheric scale height. Altitude increases to the right, and, for this immersion light curve, time increases to the left. This light curve shows many of the characteristics discussed in this paper such as multiple examples of resolved spikes, some that reach higher than the unocculted flux level, and some that are observed out to 45 scale heights with wider spacing and decreased maximum flux. — astro-ph.EP

The signatures of waves are seen during many high-quality ground-based refractive stellar occultations by solar system atmospheres.

We present a new forward-modeling technique for ground-based stellar occultations based on wavelet decomposition. If profiles of refractivity are written as the product of an exponential and a wavelet decomposition, then we can analytically write the profiles of the bending angles and the bending angle derivatives that are needed to calculate occultation light curves.

Requiring that the atmosphere is statically stable places limits on the amplitudes of atmospheric waves and their effect on the observed light curve.

Leslie A. Young, Michael J. Person

Comments: Accepted September 11, 2025 in Planetary Science Journal. Paper and machine-readable tables are at first author’s homepage, this https URL
Subjects: Earth and Planetary Astrophysics (astro-ph.EP)
Cite as: arXiv:2509.10145 [astro-ph.EP] (or arXiv:2509.10145v1 [astro-ph.EP] for this version)
https://doi.org/10.48550/arXiv.2509.10145
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Submission history
From: Leslie Young
[v1] Fri, 12 Sep 2025 11:16:27 UTC (2,713 KB)
https://arxiv.org/abs/2509.10145
Astrobiology,

Keith Cowing

Biologist, Explorers Club Fellow, ex-NASA Space Biologist and Payload integrator, Editor of NASAWatch.com and Astrobiology.com, Lapsed climber, Explorer, Synaesthete, Former Challenger Center board member 🖖🏻

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