DIRECT DETECTION OF SEASONAL CHANGES ON TRITON WITH HUBBLE SPACE TELESCOPE

Triton is one of the few bodies in the solar system with observed cryo-volcanic activity, in the form of plumes at its south pole, which suggests large-scale surface volatile transport over time. Triton's large variations in obliquity have motivated prior predictions of changing atmospheric column densities of several orders of magnitude, driven by seasonal evaporation of surface volatiles. Using the Hubble Space Telescope, we directly imaged Triton's surface and have detected large-scale differences in increased and decreased reflectance when compared with Voyager data at UV, visual, and methane-band wavelengths. Our surface map shows regions of increased brightness at near-equatorial latitudes and near the Neptune-facing side, and darkened regions near longitudes of ±180°, indicating the presence of ongoing seasonal volatile transport.

[1]  Eliot F. Young,et al.  Photometric analysis of 1 Ceres and surface mapping from HST observations , 2006 .

[2]  D. Tholen,et al.  The brightness and lightcurve of Triton in 1987 , 1989 .

[3]  Michael E. Brown,et al.  Near-Infrared Spectroscopy of Centaurs and Irregular Satellites , 2000 .

[4]  S. Stern,et al.  HST/FOC Imaging of Triton , 2001 .

[5]  J. Goguen,et al.  V photometry of Titania, Oberon, and Triton , 1989 .

[6]  O. Franz.  UBV photometry of Triton , 1981 .

[7]  Christopher T. Russell,et al.  The Shape and Surface Variation of 2 Pallas from the Hubble Space Telescope , 2009, Science.

[8]  B. Buratti,et al.  The spectral variability of Triton from 1997–2000 , 2004 .

[9]  T. Owen,et al.  Composition, Physical State, and Distribution of Ices at the Surface of Triton , 1999 .

[10]  Eliot F. Young,et al.  PLUTO AND CHARON WITH THE HUBBLE SPACE TELESCOPE. I. MONITORING GLOBAL CHANGE AND IMPROVED SURFACE PROPERTIES FROM LIGHT CURVES , 2010 .

[11]  S. Squyres,et al.  Thermal stress tectonics on the satellites of Saturn and Uranus , 1991 .

[12]  J. Pasachoff,et al.  Global warming on Triton , 1998, Nature.

[13]  P. Thomas.  The Shape of Triton from Limb Profiles , 2000 .

[14]  L. Trafton.  Large seasonal variations in Triton's atmosphere , 1984 .

[15]  J. Veverka,et al.  Photometric diversity of terrains on Triton , 1994 .

[16]  W. Grundy,et al.  Near-infrared spectral monitoring of Triton with IRTF/SpeX II: Spatial distribution and evolution of ices , 2009, 0908.2623.

[17]  W. Grundy,et al.  Near-infrared spectral monitoring of Triton with IRTF/SpeX I: establishing a baseline for rotational variability , 2004 .

[18]  G. Orton,et al.  A TENTATIVE IDENTIFICATION OF HCN ICE ON TRITON , 2010 .