Engineering topics
Publications and source records attributed to Cruikshank, D. P..
The Ka'u Desert lies southwest of Kilauea Volcano. The region contains some of the most interesting and best preserved volcanic features found in the islands. The structural setting and synopsis of recent volcanic activity on the Ka'u Desert are discussed here, and a field guide to Mauna Iki is provided.
The extensive photometric observations of Titan, Iapetus, Rhea, Dione and Tethys have made it possible to separate the solar phase and orbital phase contributions to the observed light variations of these satellites. For Titan, the wavelength dependence of its solar phase coefficient has been obtained. This dependence should prove useful in constructing future model atmospheres. The other four satellites show a surprising array of different photometric behaviors. Despite these differences, all four satellites have similar spectral reflectivities. Clearly Iapetus, Rhea, Dione and Tethys are complex objects, varying substantially from one another in surface structure and/or composition.
Review of the physical nature of all of the known satellites except the moon. Following a summary of the basic data regarding the size, mass, and density of satellite systems and a description of models that have been proposed for the composition and structure of these systems, a detailed analysis is made of the satellites of Mars, the Galilean satellites, Titan, the other satellites of Saturn, the rings of Saturn, and the remaining objects, with emphasis on studies of their surfaces by imaging, photometry, spectrophotometry, polarimetry, and radiometry.
The following radii (in kilometers) and visual geometric albedos are derived for nine asteroids from 10- and 20-micron radiometry: 1 Ceres (540, .06); 2 Pallas (275, .08); 3 Juno (125, .14); 4 Vesta (270, .21); 6 Hebe (110, .16); 15 Eunomia (135, .15); 51 Nemausa (80, .05); 433 Eros (12, .07); and 511 Davida (180, .04). Vesta has the highest albedo measured for an asteroid, while Davida, the lowest-albedo object in the sample, is one of the darkest known objects in the solar system. The median of all asteroid albedos measured to date is 0.1.-
Review of the photometric work on eclipse reappearances of Io. New observations of eclipse reappearances of Io confirm the posteclipse brightness anomaly reported by Binder and Cruikshank (1964) but testify to its intermittent nature. A posteclipse anomaly of approximately 0.07 mag was observed on two occasions in 1972, while observations of Europa and Ganymede showed no brightness anomaly greater than 0.01 mag. The atmospheric condensation model for the anomaly on Io is reviewed in terms of the quantity of frost required to produce the effect and the corresponding amount of gas liberated to the atmosphere upon sublimation. The observational data and the results from a stellar occultation are in general accord with the theoretical predictions of the stability of heavy gases on Io, while both observational and theoretical criteria are satisfied by a tenuous atmosphere of a heavy gas such as methane or ammonia having a surface pressure of about 0.1 microbar.
This paper discusses formation of 'pathological' cases of crater morphology due to interaction of craters with molten lavas. Terrestrial observations of such a process are discussed. In lunar maria, a number of small impact craters (D less than 10 km) may have been covered by thin layers of fluid lavas, or formed in molten lava. Some specific lunar examples are discussed, including unusual shallow rings resembling experimental craters deformed by isostatic filling.
The employment of a high-resolution Fourier Transform Spectrometer (FTS) is described for planetary and other astronomical spectroscopy in conjunction with the 88-inch telescope at Mauna Kea Observatory. The FTS system is designed for a broad range of uses, including double-beam laboratory spectroscopy, infrared gas chromatography, and nuclear magnetic resonance spectroscopy. The data system is well-suited to astronomical applications because of its great speed in acquiring and transforming data, and because of the enormous storage capability of the magnetic tape unit supplied with the system. The basic instrument is outlined 2nd some of the initial results from the first attempted use on the Mauna Kea 88-inch telescope are reported.
Radiometry in the 20-micron band of eclipses of each of the four Galilean satellites of Jupiter provides information about the thermal properties of the uppermost surface layers of these bodies. Their thermal inertias are all smaller than those of the moon or of Mercury; there is no evidence for atmospheres, and where the data are of high quality vertically homogeneous thermal properties are excluded. The thermal properties, together with other observational evidence, suggest that the surfaces of these satellites are largely composed of ices. A thin coating of frost provides the upper, low-conductivity layer, while the subsurface material maintains a high thermal conductivity by fusion of a mixture of ice and rock.
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Determination of the effective temperatures of the satellites by means of broad-band observations made at Mauna Kea in 1971. The temperatures of the Galilean satellites are in fair agreement with observations at shorter wavelengths and with theory. The 20-micron flux of Titan is nearly an order of magnitude lower than expected, suggesting either low surface emissivity or high atmospheric opacity between 18 and 25 micron. Hydrogen could produce the required opacity, but the abundance needed is large.
Study of the origin and development of lava conduits in terrestrial volcanic regions and the possible association of two important classes of lunar morphological features - i.e., channels and the sinuous rilles on the lunar maria - with stages in the evolution of lava conduits. The study was motivated by observations of some Hawaiian active volcanic regions. The origin of apparent flow channels on steep slopes on the moon is also considered.
Examination of the observational basis for Kuiper's (1969) conclusion that the upper cloud layers of Venus are composed of dihydrated ferrous chloride particles. Using new spectrophotometric observations of Venus, it is found that there is no strong evidence for the Fe(2+) electronic band near 1 micron as deduced by Kuiper from the photometry of Venus by Irvine et al. (1968). Evidence for an absorption band on Venus near 0.5 micron is found to be valid, but nondefinitive in terms of the identification of ferrous iron. An absorption band near 0.39 micron appearing in the Venus photometric data of Irvine et al. (1968) is judged to be unreliable as an indicator of chemical composition, because of time-dependent variations in the violet and ultraviolet clouds and spectrum of Venus. In conclusion, it is found that the evidence for dihydrated ferrous chloride in the atmosphere of Venus is inconclusive.
Ganymede thermal inertia data from simultaneous visual photometry and IR radiometry observations during 17 March 1971 eclipse
Mars surface pressure and elevation differences determined by spectroscopic observation of carbon dioxide band
Low hygrometer calibration for water vapor measurements smaller than 3 mm
IR reflectance studies of lunar surface composition, showing absorption spectra suggestive of ferrous iron, olivines and orthopyroxenes