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161.
Philip R. Maloney 《Astrophysics and Space Science》1997,248(1-2):105-112
NGC 1068 is a source of luminous emission in the near-infrared lines of molecular hydrogen and [Fe II]. Although these emission lines are commonly attributed to shocks, I show that in NGC 1068 it is quite plausible that they arise in the X-Ray Dissociation Region (XDR) produced by X-ray irradiation of the gas in the disk by the powerful active nucleus. This mechanism naturally produces the observed size scale of the H2 emission. I will also briefly discuss the implications of the observations of the pure rotation lines of H2 with ISO (Lutz, this workshop). 相似文献
162.
163.
Summary All of the barium and marginal barium stars in the 1972 MacConnell, Frey, and Upgren (1972: MFU) list of such objects which
are located south of the celestial equator were examined for visual duplicity. Over 200 objects were observed, and a total
of six possible candidates for wide pair visual binaries were found. Of these, four are most likely optical in nature. These
data suggest that the incidence of wide binaries among barium stars is of the order of 1%. 相似文献
164.
Philip B. James 《Icarus》1982,52(3):565-569
The 1979–1980 regression curve for the north polar cap of Mars, determined from Viking orbiter images, is compared to Viking observations of the same season 1 (Martin) year earlier and to telescopic observations. Differences between the two years cannot unambigously be attributed to dynamical effects because of uncertainties introduced by limited longitudinal coverage. 相似文献
165.
166.
Summary. The governing equation derived by England & M c Kenzie for the deformation of a thin viscous shell contains an error. We give the correct derivation here and correct those figures where the change makes a visible difference. The correct results differ quantitatively from those of England & M c Kenzie but their conclusions are not affected. 相似文献
167.
Previously published dispersion fields on ternary diagrams have been constructed variously, and their derivations have not been well-specified. Here an explanation of their bases is provided through an algebraic method for calculating two related forms, designated thesilhouette dispersion field and thegirth dispersion field. Such dispersion estimates can be made more precise by specifying the percentage of samples that fall within the field. Because such fields represent a mechanistic rather than a probabilistic approach, their use in comparison of sample sets must be viewed with caution. 相似文献
168.
Photons in the energy region above 10 MeV can provide unique information about the highest energy particles produced in solar flares. Measurements of the energy spectra, temporal behavior and anisotropies of the incident photons, can give valuable insights into the particle acceleration process. In this paper we review the detection techniques used at these energies, typical instruments which use these techniques, and future solar missions both actual and potential. 相似文献
169.
170.
Philip J. Stooke 《Earth, Moon, and Planets》1992,56(2):123-139
A topographic model of Amalthea (JV) was derived from the shapes of limbs and terminators in Voyager images, modified locally to accommodate large craters and ridges. The model is presented in tabular and graphic form, including the first detailed shaded relief maps of the satellite. The shape is very irregular, with radii varying between about 53 and 151 ± 5 km. The minimum value occurs in a deep crater at the south pole. The volume is estimated to be 2.5 ± 0.5 × 106km3. A prominent groove or valley extends some 150 km across the trailing side. High albedo, spectrally distinct markings are mapped and found to have a less obvious relationship with relief than previously suggested. 相似文献