![Numerical computations corresponding to the candidate pattern in the H–alpha filter (λ0 = 656 nm), for the total flux (left) and the polarized flux (right). The background polarization signal has been subtracted from the latter. The decrease in spatial resolution due to the Earth’s atmosphere is not included. The planetary atmosphere is assumed to be horizontally homogeneous except for the gas density variations. -- [astro-ph.EP]](https://i0.wp.com/astrobiology.com/wp-content/uploads/2026/07/Planet-wide.png?fit=1200%2C668&ssl=1)
[astro-ph.EP] We report observations of faint (10−6), concentric, planet-wide rings in the polarized flux of sunlight that is reflected by Venus, obtained during a serendipitous, 36-minute run in 2010, with the highly sensitive Extreme Polarimeter (ExPo) on the William Herschel Telescope.
The rings appear to be centered slightly downwind of the sub-solar point, are visible in different filters across the visible, and are not obvious in the simultaneous total flux observations. ExPo’s dual-beam exchange and double-differencing design strongly suppresses first-order instrumental polarization, and we could not identify an instrumental cause of the observed pattern.
Because ExPo was dismantled before the rings were identified in the data, this is the only set of observations of these rings. We are therefore careful in claiming the detection of a new atmospheric phenomenon on Venus.
However, numerical radiative transfer simulations show that planet-wide rings in polarization can arise due to density variations of 5 to 10% in the gas above the clouds, consistent with a gravity wave. Our simulations also show that such density variations would not show up in total flux observations.
By presenting our observations and numerical simulations, we hope to motivate new polarimetric observations of Venus that could confirm or refute the presence of such planet-wide waves.
Gourav Mahapatra, Michiel Rodenhuis, Frans Snik, Daphne M. Stam, Loïc Rossi, Christoph Keller
Comments: 19 pages, 11 figures. Published in The Planetary Science Journal
Subjects: Earth and Planetary Astrophysics (astro-ph.EP)
Cite as: arXiv:2607.16557 [astro-ph.EP] (or arXiv:2607.16557v1 [astro-ph.EP] for this version)
https://doi.org/10.48550/arXiv.2607.16557
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Journal reference: The Planetary Science Journal, 7, 169 (2026)
Related DOI:
https://doi.org/10.3847/PSJ/ae7e6f
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Submission history
From: Gourav Mahapatra
[v1] Fri, 17 Jul 2026 23:58:02 UTC (4,410 KB)
https://arxiv.org/abs/2607.16557
Astrobiology, Astrochemistry, Astrogeology,
