Coordinated 1996 HST and IRTF Imaging of Neptune and Triton: II. Implications of Disk-Integrated Photometry

✍ Scribed by L.A. Sromovsky; P.M. Fry; K.H. Baines; T.E. Dowling

• Publisher: Elsevier Science
• Year: 2001
• Tongue: English
• Weight: 441 KB
• Volume: 149
• Category: Article
• ISSN: 0019-1035
• DOI: 10.1006/icar.2000.6563

✦ Synopsis

Near-IR groundbased observations coordinated with Wide Field Planetary Camera 2 (WFPC2) HST observations (Sromovsky et al. Icarus 149, 416-434, 459-488) provide new insights into the variations of Neptune and Triton over a variety of time scales. From 1996 WFPC2 imaging we find that a broad circumpolar nonaxisymmetric dark band dominates Neptune's lightcurve at 0.467 µm, while three discrete bright features dominate the lightcurve at longer wavelengths, with amplitudes of 0.5% at 0.467 µm and 22% at 0.89 µm, but of opposite phases. The 0.89-µm modulation in 1994, estimated at 39%, is close to the 50% modulation observed during the 1986 "outburst" documented by Hammel et al. (1992, Icarus 99, 363-367), suggesting that the unusual 1994 cloud morphology might also have been present in 1986. Lightcurve amplitudes in