Bolometric albedos of Titan, Uranus, and Neptune

The geometric albedos of Titan, Uranus, and Neptune have been measured from 2000 to 3175 Å by J. Caldwell, T. Owen, A. R. Rivolo, V. Moore, G. E. Hunt, and P. S. Butterworth (1981, Astron. J. 86, 298–305), from 3500 to 10,500 Å by J.S. Neff, D. C. Humm, J. T. Bergstralh, A. L. Cochran, W. D. Cochran, E. S. Barker, and R. G. Tull (1984, Icarus 60, 221–235), and from 6440 to 25,360 Å by J. Apt, R. N. Singer, and R. N. Clark (private communication). The integrated solar flux in this spectral interval amounts to 97% of the solar constant. These data sets were combined and integrated to find the bolometric geometric albedo of each object. Preliminary determinations of the phase functions were used to compute the Bond albedos and effective temperatures. The effective temperatures are compared with bolometric temperatures determined from brightness temperatures in the 10-μm to 5-mm region of the spectrum. An improved value for the internal luminosity of Neptune is (3.9 ± 1.1) × 10 15 W and an upper limit to the internal luminosity of Uranus