Saturn's North and South aurora observed by Cassini camera in visible wavelengths.

+ UVIS simultaneous observationsUlyana A. Dyudina, Danika F. Wellington, Shawn P. Ewald,

Andrew P. Ingersoll.+ Wayne Prior et al.

Aurora Australis

SpectrumMeasuredby Cassini

Lab simulation

(Aguilar et al. ApJ. 177, 2008)

Rayleigh/nm

Saturn periodicities

Saturn day 0

Day 2

Day 5

Day 7

Saturn periodicities

Saturn day 0

Day 2

Day 5

Day 7

Voyager SKR period: 10.6564±0.002 h

Our Aurora period = Voyager’s= = 10.65±0.06 h

SKR rotation period

Gurtett, et al. GRL 37, L24101, 2010

10.65±0.06 h

Nov. 2010 aurora

Nov. 2010 aurora

Nov. 2010 aurora

Nov. 2010 aurora

Nov. 2010 aurora

...+ UVIS simultaneous observations

…+ Wayne Prior et al.

Rev 119 UVIS data (2009 day 280) painted on Saturn:

UVIS 2009 day 280 data for ISS snakes

281T00:07

ISS “snakes” 280T23:00

UVIS FUV 60 mrad long low-res (1.5 mrad wide) slit is aligned E-W, spatial sectors 27-32 (out of 0-59) overlap ISS NAC and the “Snake” features

As time progresses (upwards in UVIS image) bursty quasi-periodic features rotate across Saturn’s nightside

Night Side UVIS counts time-series: bright bursts are deep, show up more at long wavelengths (short wavelengths are absorbed by methane)

Figure from Gustin et al. 2008• Large methane

columns above snakes, other nightside spots imply electron penetration hundreds of km below usual ~1100 km auroras found by Gerard et al. 2009

• Visually, “curtains” at limb are higher than “snakes”

• Tests methane distribution models

snake

✚

ConclusionsAurora is ~1200 km tall

Aurora is few hundred km above Saturn’s “surface”, bright events are deeper

Aurora may form double curtain

Aurora is red

Auroral rotation matches SKR rotation period

I would love your suggestions on planning auroral observations with ISS