F ring Nicole Albers
Update
UVIS Team Meeting, Boulder, 23­25th.June 2008
Nicole Albers
UVIS Team Meeting, Boulder, 23­25th.June 2008
Nicole Albers
UVIS Team Meeting, Boulder, 23­25th.June 2008
66 radial cuts at various longitudes and times
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peak optical depth: 0≤max ≤4
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equivalent width: W =∫  dr ; 4.8≤W ≤50.8
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87% of all occ and km max  0.5
W  20
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on average: km  ~ 0.1−0.3 ; W ~ 10
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±100
orbital model of Bosh et al. (2002) accurate within km
●
Nicole Albers
UVIS Team Meeting, Boulder, 23­25th.June 2008
Bosh et al. (2002,Table V)
+
equivalent width in HSP data
Nicole Albers
UVIS Team Meeting, Boulder, 23­25th.June 2008
­­­ Bosh et al. (2002, orbit model)
+ core position in occ data +
Nicole Albers
UVIS Team Meeting, Boulder, 23­25th.June 2008
­­­ orbital fit based on Cassini HSP
and Voyager PPS
+ core position occ data +
Nicole Albers
UVIS Team Meeting, Boulder, 23­25th.June 2008
Semimajor Eccentricity Long. of Precession Rate Inclination Long. of ascending axis [km] x 1e­3 pericenter [deg] [deg/day] [deg] node [deg] Bosh et al. (2002,#3):140223.7±2.0
2.54±0.05
24.1±1.6
2.7001±0.0004
0.0065±0.0007
16.1±3.6
New elements: 140215.3±1.2
2.33±0.01
23.2±0.5
2.7003±0.0002
0.0082±0.0005
4.2±4.1
Linked node precession: −2.6878±0.0002
Nicole Albers
UVIS Team Meeting, Boulder, 23­25th.June 2008
Semimajor Eccentricity Long. of Precession Rate Inclination Long. of ascending axis [km] x 1e­3 pericenter [deg] [deg/day] [deg] node [deg] Bosh et al. (2002,#3):140223.7±2.0
2.54±0.05
24.1±1.6
2.7001±0.0004
0.0065±0.0007
16.1±3.6
New elements: 140215.3±1.2
2.33±0.01
23.2±0.5
2.7003±0.0002
0.0082±0.0005
4.2±4.1
Linked node precession: −2.6878±0.0002
Nicole Albers
UVIS Team Meeting, Boulder, 23­25th.June 2008
Nicole Albers
UVIS Team Meeting, Boulder, 23­25th.June 2008
semimajor axis = km 140,020
eccentricity = 0.002
Nicole Albers
UVIS Team Meeting, Boulder, 23­25th.June 2008
Nicole Albers
UVIS Team Meeting, Boulder, 23­25th.June 2008
Summary
F ring is well described by a precessing ellipse in UVIS HSP
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±20
measure of the core's “kinks” is km but can reach up to km 40
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core­like feature in recent occs is about 200 km inward from main core but is rather an arc than a complete ring ­> tracer of violent collision that shed a lot of material? ●
if persistent it will suffer a very close encounter with Prometheus
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recent high­res images support bands of material next to main core but also note the existence of “fans” ­> chances are high we cut through a “fan” like through a propeller ­> could some features in HSP be actually fans? ­> if thus indirectly a moonlet their number density decreases ●
Nicole Albers
UVIS Team Meeting, Boulder, 23­25th.June 2008
Murray et al. (2008, Fig.1)
Nicole Albers
UVIS Team Meeting, Boulder, 23­25th.June 2008
Murray et al. (2008, Fig.3)
Nicole Albers
UVIS Team Meeting, Boulder, 23­25th.June 2008
Murray et al. (2008, Fig.4)
Nicole Albers
UVIS Team Meeting, Boulder, 23­25th.June 2008