Voyager 2 at Neptune: Imaging Science Results

• Published in: Science (American Association for the Advancement of Science) Vol. 246; no. 4936; pp. 1422 - 1449
• Main Authors: Smith, B. A., Soderblom, L. A., Banfield, D., Barnet, C., Basilevksy, A. T., Beebe, R. F., Bollinger, K., Boyce, J. M., Brahic, A., Briggs, G. A., Brown, R. H., Chyba, C., Collins, S. A., Colvin, T., Cook, A. F., Crisp, D., Croft, S. K., Cruikshank, D., Cuzzi, J. N., Danielson, G. E., Davies, M. E., De Jong, E., Dones, L., Godfrey, D., Goguen, J., Grenier, I., Haemmerle, V. R., Hammel, H., Hansen, C. J., Helfenstein, C. P., Howell, C., Hunt, G. E., Ingersoll, A. P., Johnson, T. V., Kargel, J., Kirk, R., Kuehn, D. I., Limaye, S., Masursky, H., McEwen, A., Morrison, D., Owen, T., Owen, W., Pollack, J. B., Porco, C. C., Rages, K., Rogers, P., Rudy, D., Sagan, C., Schwartz, J., Shoemaker, E. M., Showalter, M., Sicardy, B., Simonelli, D., Spencer, J., Sromovsky, L. A., Stoker, C., Strom, R. G., Suomi, V. E., Synott, S. P., Terrile, R. J., Thomas, P., Thompson, W. R., Verbiscer, A., Veverka, J.
• Format: Journal Article
• Language: English
• Published: Legacy CDMS The American Association for the Advancement of Science 15.12.1989; American Association for the Advancement of Science
• Subjects: 640107 - Astrophysics & Cosmology- Planetary Phenomena; Albedo; ALKANES; Altitude; AMMONIA; Artificial satellites; Astronomy; ATMOSPHERES; CAVITIES; CHALCOGENIDES; CHEMICAL COMPOSITION; CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; CLOUDS; CRATERS; Earth, ocean, space; Exact sciences and technology; HYDRIDES; HYDROCARBONS; HYDROGEN COMPOUNDS; HYDROGEN SULFIDES; Impact craters; Lunar And Planetary Exploration; METHANE; Neptune; NEPTUNE PLANET; Neptunian satellites; NITROGEN COMPOUNDS; NITROGEN HYDRIDES; Observations; Occultations; Occultations (Astronomy); Optical thickness; ORGANIC COMPOUNDS; PLANETARY ATMOSPHERES; PLANETS; Planets, their satellites and rings. Asteroids; Plumes; RINGS; SATELLITES; Satellites (Astronomical bodies); Solar system; Space exploration; SPACE VEHICLES; SULFIDES; SULFUR COMPOUNDS; Triton (Satellite); VEHICLES; Voyager 2; VOYAGER SPACE PROBES; Neptune satellite; Planetary atmosphere; Neptune; Planetary ring; Planetary albedo; Physical parameter; Abundance; Satellite observation; Finding chart
• ISSN: 0036-8075; 1095-9203
• DOI: 10.1126/science.246.4936.1422

Voyager 2 images of Neptune reveal a windy planet characterized by bright clouds of methane ice suspended in an exceptionally clear atmosphere above a lower deck of hydrogen sulfide or ammonia ices. Neptune's atmosphere is dominated by a large anticyclonic storm system that has been named the Great Dark Spot (GDS). About the same size as Earth in extent, the GDS bears both many similarities and some differences to the Great Red Spot of Jupiter. Neptune's zonal wind profile is remarkably similar to that of Uranus. Neptune has three major rings at radii of 42,000, 53,000, and 63,000 kilometers. The outer ring contains three higher density arc-like segments that were apparently responsible for most of the ground-based occultation events observed during the current decade. Like the rings of Uranus, the Neptune rings are composed of very dark material; unlike that of Uranus, the Neptune system is very dusty. Six new regular satellites were found, with dark surfaces and radii ranging from 200 to 25 kilometers. All lie inside the orbit of Triton and the inner four are located within the ring system. Triton is seen to be a differentiated body, with a radius of 1350 kilometers and a density of 2.1 grams per cubic centimeter; it exhibits clear evidence of early episodes of surface melting. A now rigid crust of what is probably water ice is overlain with a brilliant coating of nitrogen frost, slightly darkened and reddened with organic polymer material. Streaks of organic polymer suggest seasonal winds strong enough to move particles of micrometer size or larger, once they become airborne. At least two active plumes were seen, carrying dark material 8 kilometers above the surface before being transported downstream by high level winds. The plumes may be driven by solar heating and the subsequent violent vaporization of subsurface nitrogen.