The photometric observation of the quasi-simultaneous mutual eclipse and occultation between Europa and Ganymede on 22 August 2021

Mutual events (MEs) are eclipses and occultations among planetary natural satellites. Most of the time, eclipses and occultations occur separately. However, the same satellite pair will exhibit an eclipse and an occultation quasi-simultaneously under particular orbital configurations. This kind of r...

Full description

Saved in:
Bibliographic Details
Published in:arXiv.org 2022-12
Main Authors: Chu Wing So, Godfrey Ho Ching Luk, Giann On Ching Chung, Leung, Po Kin, Kenneith Ho Keung Hui, Chung Cheung, Jack Lap, Chan, Ka Wo, Edwin Lok Hei Yuen, Kwan Lee, Lawrence Wai, Ip Lau, Patrick Kai, Gloria Wing Shan Cheung, Lam Chan, Prince Chun, Jason Chun Shing Pun
Format: Article
Language:English
Subjects:
CCD cameras
Eclipses
Ephemerides
Europa
Ganymede
Jupiter satellites
Light curve
Model accuracy
Natural satellites
Occultation
Photometry
Satellite observation
Solar system
Online Access:Get full text
Tags: Add Tag
No Tags, Be the first to tag this record!
Description
Summary:Mutual events (MEs) are eclipses and occultations among planetary natural satellites. Most of the time, eclipses and occultations occur separately. However, the same satellite pair will exhibit an eclipse and an occultation quasi-simultaneously under particular orbital configurations. This kind of rare event is termed as a quasi-simultaneous mutual event (QSME). During the 2021 campaign of mutual events of jovian satellites, we observed a QSME between Europa and Ganymede. The present study aims to describe and study the event in detail. We observed the QSME with a CCD camera attached to a 300-mm telescope at the Hong Kong Space Museum Sai Kung iObservatory. We obtained the combined flux of Europa and Ganymede from aperture photometry. A geometric model was developed to explain the light curve observed. Our results are compared with theoretical predictions (O-C). We found that our simple geometric model can explain the QSME fairly accurately, and the QSME light curve is a superposition of the light curves of an eclipse and an occultation. Notably, the observed flux drops are within 2.6% of the theoretical predictions. The size of the event central time O-Cs ranges from -14.4 to 43.2 s. Both O-Cs of flux drop and timing are comparable to other studies adopting more complicated models. Given the event rarity, model simplicity and accuracy, we encourage more observations and analysis on QSMEs to improve Solar System ephemerides.
ISSN:2331-8422
DOI:10.48550/arxiv.2212.05215