Location of Saturn's Northern Infrared Aurora Determined from Cassini VIMS Images

The location of Saturn's northern infrared aurora is described in detail using 12 selected images acquired by Cassini VIMS during 2006–2008. Bright main oval arcs and prevalent polar features are displayed, which do not exhibit a preferred local time or spatial extent. The average equatorward limit of the aurora was determined using a best fit circle method. The average circle has a radius of 16.4 ± 0.2° latitude, centred 1.6° anti-sunward of Saturn's pole. The low standard deviation of the fitted circle radii (<1°) indicates the relative stability of the equatorward auroral boundary. For the first time we show that the average location of the infrared oval is similar to that of the ultraviolet oval, suggesting that the auroral emissions at different wavelengths are very likely produced by a common driver despite the distinct emission mechanisms.