Comets and Asteroids

Water Production Rates from SOHO/SWAN Observations of Comets C/2020 S3 (Erasmus), C/2021 A1 (Leonard) and C/2021 O3 (PanSTARRS)

By Keith Cowing
Status Report
April 11, 2023
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Water Production Rates from SOHO/SWAN Observations of Comets C/2020 S3 (Erasmus), C/2021 A1 (Leonard) and C/2021 O3 (PanSTARRS)
Water production rate in comet C/2021 A1 (Leonard) as a function of time from perihelion. The points give the water production rate in s-1 from single images. The error bars give the 1-s formal random fitting errors for each value. There is a ~30% uncertainty from the model parameters and calibration. — astro-ph.EP

In 2021 and 2022 the hydrogen comae of three long period comets, C/2020 S3 (Erasmus), C/2021 A1 (Leonard) and C/2021 O3 (PanSTARRS) were observed with the Solar Wind ANisotropies (SWAN) all-sky hydrogen Lyman-alpha camera on the SOlar and Heliosphere Observer (SOHO) satellite.

SWAN obtains nearly daily full-sky images of the hydrogen Lyman-alpha distribution of the interstellar hydrogen as it passes through the solar system yielding information about the solar wind and solar ultraviolet fluxes that eats away at it by ionization and charge exchange. The hydrogen comae of comets, when of sufficient brightness, are also observed. Water production rates have been calculated over time for each of these comets.

Of particular interest are comet C/2021 O3 (PanSTARRS) which apparently disintegrated a few days before its perihelion at 0.28 au and C/2021 A1 (Leonard) which also disintegrated beginning about 20 days after its perihelion peak. The behavior of comet C/2020 S3 (Erasmus) was more typical without dramatic fading, but still was asymmetric about perihelion, with a more rapid turn on before perihelion and more extended activity well after perihelion.

M.R. Combi, T. Mäkinen, J.-L. Bertaux, E. Quémerais, S. Ferron

Comments: 20 pages, 4 Figures, 4 Tables
Subjects: Earth and Planetary Astrophysics (astro-ph.EP)
Cite as: arXiv:2304.03333 [astro-ph.EP] (or arXiv:2304.03333v1 [astro-ph.EP] for this version)
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Journal reference: Icarus 398, 115543, 2023
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Submission history
From: Michael Combi
[v1] Thu, 6 Apr 2023 19:04:27 UTC (790 KB)
Astrobiology, Astrochemistry,

SpaceRef co-founder, Explorers Club Fellow, ex-NASA, Away Teams, Journalist, Space & Astrobiology, Lapsed climber.