Engineering topics

Brown, Robert H.

Publications and source records attributed to Brown, Robert H..

21 records · Page 2

NASA NTRS1988

Volatiles on Triton - The infrared spectral evidence, 2.0-2.5 microns

The new IR spectra presented for Triton exhibit the 2.3-micron methane band as well as Cruikshank et al.'s (1984) 2.15-micron spectral band. It is found on the basis of comparisons with methane ice spectra, and laboratory spectra of methane dissolved in liquid nitrogen, that the former band cannot be exclusively due to methane's presence. Also, the strength of the 2.3-micron band does not allow any obvious correlation with the satellite's orbital position in the new data set.

Cruikshank, Dale P.↗

NASA NTRS1987

Uranus satellites - Densities and composition

Homogeneous and core-differentiated silicate/ice models of the Uranian satellites Miranda, Ariel, Umbriel, Titania, and Oberon are examined in the light of imaging observations and mass and density determinations obtained during the Voyager 2 encounter with Uranus in January 1986. The data and model predictions are compared in extensive tables and graphs and discussed in detail. The mass fractions of silicates in Oberon and Titania are found to be between 0.42 and 0.65, about the same as the average for the satellites of Jupiter and Saturn but significantly higher than that for the smaller Saturnian satellites or that predicted by current solar-nebula models. It is suggested that the satellites formed by accretion of material from their primary planets' outer envelopes. The observed rock/ice fractions are attributed to solar-nebula CO and solid-organics abundances and to preferential dissolution of H2O in outer-envelope planetesimals.

Johnson, Torrence V.↗

NASA NTRS1987

Infrared radiometry of Uranus and Neptune at 21 and 32 microns

Mauna Kea's NASA IRTF has been used to obtain 21- and 32-cm radiometric measurements of Uranus and Neptune; brightness temperatures of 54.1 + or - 0.3 K for Uranus and 58.1 + or 0.3 K for Neptune were obtained by calibrating the 21-cm data against Alpha Boo. A calibration of the 32-cm data against Callisto and Ganymede yielded respective temperatures of 51.8 + or - 1.5 K and 55.6 + or - 1.2 K. The general decrease of brightness temperatures with wavelength from 20 to 30 microns is confirmed. The two planets are noted to appear as bodies sufficiently different to depart from the hypothesis of smooth planetary bulk property variation as a function of heliocentric distance.

Orton, Glenn S.↗