UVIS Team Meeting June 16-18 2014 RTWT and Science Planning Report UVIS Team Meeting January 8, 2014, CalTech

Solstice Mission Inclination Profile Now UVIS Team Meeting January 8, 2014, CalTech

Ring Science SM Status Update 21 IN1 occs completed to date: Alpha Canis Majoris (168, 169 - joint w/ VIMS) Kappa Canis Majoris (168, PIE, Particle Tracking) Zeta Canis Majoris (169, PIE, Particle Tracking) Zeta Pupis (171, PIE) Gamma Pegasi (172) Alpha Virginis (173, PIE) Epsilon Canis Majoris (173, 174) Gamma Columba (173, PIE) Alpha Lyrae (175, PIE - joint w/ VIMS) Kappa Velorum (183) Delta Centauri (183, 185) Beta Libra (187, B=16 deg.) Lamba Tauri (188, PIE, B=18 deg., close to Daphnis) Theta Carinae (190, bright, B=67 deg.) Delta Dentauri (191, 194) Alpha Lyrae (202, 202 - joint w/ VIMS) UVIS Team Meeting January 8, 2014, CalTech

SM PIE Occs Tracking occs: Azimuthal structure: Eps Sgr (1.1 km/s) in 2016 Kap CMa in 2012 (June 29, completed) Zet CMa (0.1 km/s) in 2012 (July 23; completed) Zet Pup (1 km/s) in 2012 (September 3, completed) Azimuthal structure: Bet Cru (496 km from Bleriot) in 2017 Zet Cen (147 km from Daphnis) in 2016 Lam Tau (79 km from Daphnis) in 2013 (completed) Occs with VIMS (Alpha Lyrae, 3 completed, 1 more integrated) Orionis occs (low elevation angle to rings) Kap Ori 10 hour occ (2015-049) UVIS Team Meeting January 8, 2014, CalTech

UVIS Rings Science Goals for F ring and Proximal Orbits Josh Colwell, Larry Esposito, Todd Bradley, Tracy Becker, Miodrag Sremcevic

Science Goals Overview A1: Observe ring structure at high resolution to extend the temporal baseline through to the end of mission. (RC1a, RC1b) A2: Measure particle properties using synoptic occultations with VIMS. (RC1a, RN2a) A3: Measure small-scale particle structure at key areas in the rings that have not previously been observed at high resolution. (RC1a, RC1b, RN2a) B: Measure ring UV reflectance at high spatial resolution across the rings and at specific regions not previously resolved in the UV. (RC1b, RN1c)

A1. Extend Temporal Baseline of High Resolution Measurements of Ring Structure Measurement: Full radial stellar occultations observed at large B angles. Geometry: There is a series of Alpha Eridani occultations on revs 271 (and later) that cover the whole ring system. There are additional occs in the F ring orbits that are unique, some of which are better than ALPERI and some not as good. Conflicts: ALPERI occultations occur at -1.5 to 0 hours from periapse. F ring occs tend to be further from periapse.

A2. Measure Particle Properties Using Synoptic Observations with VIMS Measurement: Full radial stellar occultations of stars with good signal for VIMS and UVIS to obtain information on the population of small particles throughout the rings and specifically in regions that previous observations have hinted may have significant small particle populations. Geometry: There are three Sirius observations on revs 272, 273 and 274 that are chord occs. Rev 274 cuts through full ring system twice, meeting measurement goal of previous slide as well. Backup on rev 275 gets A and B rings only on one side. (There are two observations of Vega on revs 249 and 250 as well.) Conflicts: These occultations occur at -2 days out, lasting 8-10 hours.

A3. Measure Small-Scale Structure at Key Locations in the Rings Measurement: Targeted stellar occultations that capture ring structure at unprecedented resolution at certain locations or observe azimuthally varying structure not previously observed at UVIS resolution. The former are “particle tracking occs” where the speed of the stellar footprint in the ring particle frame is small. The latter are occultations that pass close to embedded moons or propeller objects. Geometry: Varies Conflicts: Varies

A ring “tracking occ” example

Detection of Bleriot Wakes

Stellar Occultation Requests in F Ring and Proximal Orbits

Stellar Occultation Requests in F Ring and Proximal Orbits

Stellar Occultation Requests in F Ring and Proximal Orbits

B: Ring Spectral Reflectance in UV Science Justification: Dynamically and spectrally distinct regions in the rings, such as the strong resonance density wavetrains, associated “halos”, and the trans-Keeler region, have not been resolved in the UV with the exception of unlit-face low-SNR SOI observation. Take advantage of unique F ring and proximal orbit geometries to obtain highest resolution spectral maps of targeted ring regions. Measurements: 1. Optimize pointing in VIMS-design for F ring and Proximal orbit scans. 2. Dedicated targeted UVIS observations of key ring regions.

B1. Riding with VIMS: F Ring Orbit Drift Scans First Inbound Drift Scan (COMPLITA) 12

F ring orbit (rev 255) drift scan: - 6 to -4 hours before periapse; Optimize for UVIS by orienting UVIS slit ~radially across the rings. Improves resolution by ~2x. COMPLITA Phase angle ~ 46°; about the same brightness as SOI. Resolution ~ 250 km; about the same as SOI. Ring coverage and time on rings better than SOI. 13

B2. Riding with VIMS: F Ring Orbit Drift Scans Second Inbound Drift Scan (Blue, COMPLITB) 14

F ring orbit (rev 255) drift scan; - 4 to -1 F ring orbit (rev 255) drift scan; - 4 to -1.5 hours before periapse; Optimize for UVIS by orienting UVIS slit ~radially across the rings. Improves resolution by ~2x. COMPLITB Phase angle ~ 55°; about the same brightness as SOI Resolution ~ 100-150 km; better than SOI. Ring coverage and time on rings better than SOI. 15

B3. URASPEC1: F ring orbit targeted A ring scan: - 4 to -1 B3. URASPEC1: F ring orbit targeted A ring scan: - 4 to -1.5 hours relative to periapse. Phase angle ~ 60°; same brightness as SOI. Resolution ~ 80-180 km; up to ~2x better than SOI. Duration gives SNR ~2x SOI. 16

B4. URASPEC2: F ring orbit targeted A ring drift scan: - 6 to -4 hours relative to periapse. Phase angle ~ 68°; about the same brightness as SOI Resolution ~ 200-25 km; about the same as SOI. Increased duration gives ~2x better SNR than SOI. 17

B5. URHRSPEC: F ring orbit targeted A ring observation at - 1. 5 to -0 B5. URHRSPEC: F ring orbit targeted A ring observation at - 1.5 to -0.4 hours before periapse Phase angle ~ 10-30°; ~2x brighter than SOI. Resolution ~ 30-60 km; ~5x better than SOI. Geometry and duration gives SNR ~2x SOI. 18

F ring orbit ring spectral observation requests Ride-along with VIMS drift scans: request secondary axis orientation to optimize UVIS spatial resolution. URASPEC1: 1 targeted A ring observation at (about) -4 to -1.5 hours from periapse (priority 1). URHRSPEC: 1 targeted A ring observation at -1.5 to -0.4 hours from periapse (priority 1). URASPEC2: 1 targeted A ring observation at -6 to -4 hours from periapse (priority 2). 19

B6. Riding with VIMS: Proximal Orbit Drift Scans First Inbound Drift Scan (Red, COMPLIT) 20

Proximal orbit (rev 275) drift scan: - 3 to -1 Proximal orbit (rev 275) drift scan: - 3 to -1.5 hours before periapse; Optimize for UVIS by orienting slit radially across the rings. COMPLIT Phase angle ~ 70°; comparable brightness to SOI. Resolution ~ 150 km; 25% better than SOI. SNR comparable to SOI. Full radial scan improves on SOI. 21

B7. Proximal orbit targeted A ring observation: - 3 to -1 B7. Proximal orbit targeted A ring observation: - 3 to -1.5 hours before periapse. URASPEC2 Phase angle ~ 70°-61° Phase angle ~ 65°; comparable brightness to SOI. Resolution ~ 150 km; 25% better than SOI. Duration gives SNR ~2x SOI. 22

B8. Proximal orbit (rev 275) targeted C ring scan: - 1 to -0 B8. Proximal orbit (rev 275) targeted C ring scan: - 1 to -0.2 hours before periapse. URHRSPEC. Phase angle ~ 100°; comparable brightness to SOI. Resolution ~ 20-80 km; ~5x better than SOI. SNR comparable to SOI. 23

Proximal orbit ring spectral observation requests Ride-along with VIMS drift scans: request secondary axis orientation to optimize UVIS spatial resolution. URASPEC2: 1 targeted A ring observation at -3 to -1.5 hours from periapse (priority 2). URHRSPEC: 2 targeted inner ring system observations at -1.5 to -0.2 hours from periapse (priority 1). 24

Ring UV Imaging Requests in F Ring and Proximal Orbits