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Life on Titan Moons of Saturn ? e r e h t t u o y d o b y n a e r e h t s I k u . v o g . c s n b . w w w ? m o r f e m o c s g n i r s ’ n r u t a S d i d e r e h W S N 4 1 E n e i l A . l o o h c S n o d n o L k u . c a . l u m q . s h t a m . w w w n o i s s i M i n i s s a C e h t e d i s n I d a o R d n E e l i M r e m m u S e c a p S a i d e M 9 0 0 2 e h t n i t r a p g n i k a t s l o o h c S n e e r G n o d n o L f o y t i s r e v i n U , y r a M n e e u Q y e n p e t S d n a h t e p r o M m o r f s t n e d u t s y b d e n g i s e d d n a n e t t i r W n r u t a S f o y r e t s y M e h T n o i t a i d a r l u f m r a h s ’ r a t s e h t m o r f n o i t a r o l p x E m e t s y S r a l o S e f i l s t c e t o r p h c i h w e r e h p s o m t a n A • s ’ h t r a E o t r a l i m i s o s , d l o c . r e t n u h o o t r o t o h o o t t ’ n s i t a h t e t a m i l c A • n e i l a n a e m o c e b n a c u o y w o h r e t a W • n o n o i t a m r o f n i e r o m r o f e m o h @ I T E S p u k o o L . t e n r e t n i e h t o t s s e c c a : t n u h n e i l a r u o y n o g n i o g d n a r e t u p m o c a s i d e e n u o y l l A ! t i n e h w r o f k o o l d l u o h s u o y t a h W f o t r a p a e b n a c u o y d n a e c a p s m o r f . e f i l e l p m i s s e v a w o i d a r e v i e c e r d n a t u o d n e s o t e m o h e b d l u o c – s u d a l e c n E y e h T . ) I T E S ( e c n e g i l l e t n I l a i r t s e r r e T g n i t n u H n e i l A d n a n a t i T - n r u t a S f o s n o o m o w T a r t x E r o f h c r a e S e h t t u o k c e h c g n i t n u H n e i l A . e l b i s s o p y r e v s i m e t s y s r a l o s r u o , e f i l t n e g i l l e t n i y l l a i c e p s e , f l e s r u o y e f i l n i e s l e e r e h w e m o s e f i l g n i r e v o c s i D g n i r e v o c s i d n i d e t s e r e t n i e r a u o y f I . s t i f e n e b y n a m d n a n r a e l o t e r o m t o l a s i e r e h t k n i h t I e s u a c e b m e t s y s r a l o s r e t u o e h t o t s n o i s s i m e r o m o t n i t s e v n i d l u o w I ? o t n i t s e v n i u o y d l u o w a e r a t a h w h c r a e s e r c i f i t n e i c s o t n i s d n u o p n o i l l i b a t s e v n i o t d a h u o y f I . h c r a e s e r y m o n o r t s a n i k r o w o t n o g n i o g e r o f e b y t i s r e v i n u t a s c i t a m e h t a m d e i d u t s I . e l b i s s o p s a w t i k n i h t t ’ n d i d I t u b , t u a n o r t s a n a e m o c e b o t t n a w e m e d a m h c i h w ) n o o m e h t n o k l a w o t n a m d n o c e s e h t s a w o h w t u a n o r t s A n a c i r e m A e h t ( n i r d l A z z u B d e r i m d a s y a w l a I y o b l o o h c s a s A H ? w o n e r a u o y e r e h w o t t e g u o y d i d w o n . n r u t a S f o s n o o m w e o w t d e r e v o c s i d s a h t a h t m a e t a n i o s l a m a I . n r u t a S o t n o i s s i m i n i s s a C e h t n o k r o w I d n a n r u t a S f o s g n i r e h t e t a g i t s e v n i I . y m o n o r t s a n i h c r a e s e r t u o y r r a c I ? o d u o y o d t a h W y m o n o r t s A d n a s c i t a m e h t a M f o r o s s e f o r P n o d n o L f o y t i s r e v i n U : n o i s s e f o r P y m o n o r t s A d n a y m o n o r t s A d n a , y r a M n e e u Q t i n U y m o n o r t s A y a r r u M l r a C s c i t a m e h t a M f o r o s s e f o r P s c i t a m e h t a M f o r o s s e f o r P e r e h W : e m a N y a r r u M l r a C Life on Moons of Saturn Titan How fast did DidyouknowthatEarthisn’ttheonly theyarehuge, placewhereitrains?Thereisalsoanother theymovemore placeintheSolarSystemwithlakes, slowlycreatinga Cassini go? riversandmountains.
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  • Arxiv:1912.09192V2 [Astro-Ph.EP] 24 Feb 2020
    Draft version February 25, 2020 Typeset using LATEX preprint style in AASTeX62 Photometric analyses of Saturn's small moons: Aegaeon, Methone and Pallene are dark; Helene and Calypso are bright. M. M. Hedman,1 P. Helfenstein,2 R. O. Chancia,1, 3 P. Thomas,2 E. Roussos,4 C. Paranicas,5 and A. J. Verbiscer6 1Department of Physics, University of Idaho, Moscow, ID 83844 2Cornell Center for Astrophysics and Planetary Science, Cornell University, Ithaca NY 14853 3Center for Imaging Science, Rochester Institute of Technology, Rochester NY 14623 4Max Planck Institute for Solar System Research, G¨ottingen,Germany 37077 5APL, John Hopkins University, Laurel MD 20723 6Department of Astronomy, University of Virginia, Charlottesville, VA 22904 ABSTRACT We examine the surface brightnesses of Saturn's smaller satellites using a photometric model that explicitly accounts for their elongated shapes and thus facilitates compar- isons among different moons. Analyses of Cassini imaging data with this model reveals that the moons Aegaeon, Methone and Pallene are darker than one would expect given trends previously observed among the nearby mid-sized satellites. On the other hand, the trojan moons Calypso and Helene have substantially brighter surfaces than their co-orbital companions Tethys and Dione. These observations are inconsistent with the moons' surface brightnesses being entirely controlled by the local flux of E-ring par- ticles, and therefore strongly imply that other phenomena are affecting their surface properties. The darkness of Aegaeon, Methone and Pallene is correlated with the fluxes of high-energy protons, implying that high-energy radiation is responsible for darkening these small moons. Meanwhile, Prometheus and Pandora appear to be brightened by their interactions with nearby dusty F ring, implying that enhanced dust fluxes are most likely responsible for Calypso's and Helene's excess brightness.
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