Hydrodynamic Simulations of Moonlet-induced Propellers in Saturn's Rings
- One of the biggest successes of the Cassini mission is the detection of small moons (moonlets) embedded in Saturns rings that cause S-shaped density structures in their close vicinity, called propellers. Here, we present isothermal hydrodynamic simulations of moonlet-induced propellers in Saturn's A ring that denote a further development of the original model. We find excellent agreement between these new hydrodynamic and corresponding N-body simulations. Furthermore, the hydrodynamic simulations confirm the predicted scaling laws and the analytical solution for the density in the propeller gaps. Finally, this mean field approach allows us to simulate the pattern of the giant propeller Blériot, which is too large to be modeled by direct N-body simulations. Our results are compared to two stellar occultation observations by the Cassini Ultraviolet Imaging Spectrometer (UVIS), which intersect the propeller Blériot. Best fits to the UVIS optical depth profiles are achieved for a Hill radius of 590 m, which implies a moonlet diameter ofOne of the biggest successes of the Cassini mission is the detection of small moons (moonlets) embedded in Saturns rings that cause S-shaped density structures in their close vicinity, called propellers. Here, we present isothermal hydrodynamic simulations of moonlet-induced propellers in Saturn's A ring that denote a further development of the original model. We find excellent agreement between these new hydrodynamic and corresponding N-body simulations. Furthermore, the hydrodynamic simulations confirm the predicted scaling laws and the analytical solution for the density in the propeller gaps. Finally, this mean field approach allows us to simulate the pattern of the giant propeller Blériot, which is too large to be modeled by direct N-body simulations. Our results are compared to two stellar occultation observations by the Cassini Ultraviolet Imaging Spectrometer (UVIS), which intersect the propeller Blériot. Best fits to the UVIS optical depth profiles are achieved for a Hill radius of 590 m, which implies a moonlet diameter of about 860 m. Furthermore, the model favors a kinematic shear viscosity of the surrounding ring material of ν0 = 340 cm2 s−1, a dispersion velocity in the range of 0.3 cm s−1 < c0 < 1.5 cm s−1, and a fairly high bulk viscosity 7 < ξ0/ν0 < 17. These large transport values might be overestimated by our isothermal ring model and should be reviewed by an extended model including thermal fluctuations.…
Verfasserangaben: | Martin SeißORCiDGND, Nicole AlbersORCiD, Miodrag SremčevićORCiD, Jürgen SchmidtORCiD, Heikki SaloORCiD, Michael SeilerORCiDGND, Holger HoffmannORCiDGND, Frank SpahnORCiDGND |
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DOI: | https://doi.org/10.3847/1538-3881/aaed44 |
ISSN: | 0004-6256 |
ISSN: | 1538-3881 |
Titel des übergeordneten Werks (Englisch): | The astronomical journal |
Untertitel (Englisch): | Application to Bleriot |
Verlag: | IOP Publishing Ltd. |
Verlagsort: | Bristol |
Publikationstyp: | Wissenschaftlicher Artikel |
Sprache: | Englisch |
Datum der Erstveröffentlichung: | 12.12.2018 |
Erscheinungsjahr: | 2019 |
Datum der Freischaltung: | 28.05.2021 |
Freies Schlagwort / Tag: | diffusion; hydrodynamics; planets and satellites: rings |
Band: | 157 |
Ausgabe: | 1 |
Seitenanzahl: | 11 |
Fördernde Institution: | Deutsches Zentrum fur Luft-und RaumfahrtHelmholtz AssociationGerman Aerospace Centre (DLR) [OH 1401]; Deutsche ForschungsgemeinschaftGerman Research Foundation (DFG) [Sp 384/28-1, Ho5720/1-1]; Cassini project |
Organisationseinheiten: | Mathematisch-Naturwissenschaftliche Fakultät / Institut für Physik und Astronomie |
DDC-Klassifikation: | 5 Naturwissenschaften und Mathematik / 52 Astronomie / 520 Astronomie und zugeordnete Wissenschaften |
Peer Review: | Referiert |
Publikationsweg: | Open Access / Hybrid Open-Access |
Lizenz (Deutsch): | Creative Commons - Namensnennung, 3.0 Deutschland |