| Issue |
A&A
Volume 708, April 2026
|
|
|---|---|---|
| Article Number | A369 | |
| Number of page(s) | 11 | |
| Section | Celestial mechanics and astrometry | |
| DOI | https://doi.org/10.1051/0004-6361/202557884 | |
| Published online | 23 April 2026 | |
Measuring Titan’s rapid orbital expansion combining Cassini radio science normal points and astrometry
1
Dipartimento di Ingegneria Industriale, Alma Mater Studiorum – Università di Bologna,
47121 -
Forlì (FC),
Italy
2
LTE, Observatoire de Paris, PSL Research University, CNRS, Sorbonne Université, Université de Lille 1,
Paris,
France
3
Centro Interdipartimentale di Ricerca Industriale Aerospaziale, Alma Mater Studiorum – Università di Bologna,
47121 -
Forlì (FC),
Italy
★ Corresponding author: This email address is being protected from spambots. You need JavaScript enabled to view it.
Received:
28
October
2025
Accepted:
23
February
2026
Abstract
Recent analyses of Titan’s orbital migration have yielded conflicting results regarding Saturn’s tidal dissipation (Q) at Titan’s frequency. While some studies reported a low Q consistent with resonance locking using independent radio science and astrometric datasets, subsequent work combining multiple mission datasets found a significantly higher Q, disagreeing notably with the earlier radio science findings. This study re-evaluates Titan’s migration by integrating Cassini radio science data, processed as normal points, with over a century of astrometric observations within a unified dynamical model using NOE software. Our combined analysis confirms the previously reported rapid migration rate and low Q, thus supporting the nonclassical dissipation mechanisms hypothesis.
Key words: astrometry / celestial mechanics / ephemerides / planets and satellites: dynamical evolution and stability
© The Authors 2026
Open Access article, published by EDP Sciences, under the terms of the Creative Commons Attribution License (https://creativecommons.org/licenses/by/4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
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