EmergentSageThere is utility in the rummaging through the discard pile. #3I #ATLAS #MeerKAT #OH #Lband #RadioAstronomy #InterstellarObjects #CometScience
Narrowband Solar Attenuation by 3I/ATLAS: Geometry, Physical Plausibility, and the Case for Deep Residual Analysis
The MeerKAT L‑band observation of 3I/ATLAS on 24 October 2025 provides a rare opportunity to study narrowband solar attenuation during a near‑conjunction geometry. According to ATel 17473 (Pisano et al. 2025), two ground‑state OH absorption lines were detected at a Doppler velocity of approximately −15.6 km s⁻¹, with preliminary full widths at half maximum of 0.88 km s⁻¹ (1665 MHz) and 1.26 km s⁻¹ (1667 MHz). If these values are confirmed in the final calibrated dataset, the difference in line width is larger than expected for purely thermal or isotropic outgassing and may indicate additional structure in the absorbing medium. This paper outlines the physical implications of the geometry, describes what a distant aligned observer might detect, and argues that the apparent “noise” in the published spectra warrants deeper analysis once the dataset becomes publicly available. No claims are made about non‑natural structure; the goal is to articulate why the physics alone justifies a closer look.
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