Ten Micron Photometry of 25 Stars from B8 To M7

A photometer employing a liquid hydrogen-cooled mercury-doped germanium photoconductor whose spectral response is limited to the 8 - 14 µ region by a low pass interference filter and a BaF_2 window coupled with the cell's threshold wavelength has been placed at the east arm Cassegrain focus of the 200 inch Hale telescope. Twenty-five stars have been measured. The earliest star for which two measurements have been obtained is the B8Ia star β Orionis. The latest star is the M7e star X Cygni. The brightest star, L37 X 10^(-14) watts/cm^2, is α Orionis. The carbon star DS Peg was also measured. In a two-color diagram formed with B and V there is an intrinsic increase in dispersion going to later type stars and a systematic trend away from the blackbody relation. The ratios of the stellar fluxes to those expected from blackbodies at the published stellar effective-temperatures and angular diameters are not far from one. A systematic trend exhibited may not be real because of the assumptions involved in inteferometric diameter determinations. DS Peg does not appear overly peculiar in the two-color plots, but X,Cygni falls on the opposite side of the blackbody curve ("blue excess") compared with most of the late type stars. The fluxes presented here have not been corrected for presently uncertain telescope transmission losses which may be important

Surface Temperature Variations during the Lunar Nighttime

A new photometer incorporating a mercury-doped germanium photoconductor has been used with a 19-inch telescope to measure the 8-14- brightness temperatures of the shaded lunar surface. Right- ascension scans carried into the lunar nighttime from the terminator show a characteristic of cooling inconsistent with the occurrence of a thick homogeneous dust layer. It appears th more highiy conducting material either is exposed commonly on the surface or constitutes a substratum generally covered by no more than a centimeter or so of the strongly insulating dust. No difference in nighttime temperature distribution was observed between maria and uplands. However, local areas of higher-thanaverage brightness temperature were encountered. These indicate extensive exposures of consolidated material. Local temperature anomalies of this type are associated with the bright-rayed craters Tycho and Copernicus, but they are distributed over an area larger than that represented by the respective craters. Two other groups of temperature anomalies were found in otherwise undistinguished mare border areas. These observations and others suggest that surface redistribution processes are operative on the lunar surface over at least a 10-meter range, but are not important over distances much in excess of a kilometer

Thermal infrared emission of the Jovian disk

The 8–14 micron infrared emission of Jupiter has been observed on six nights in December 1963 using the 200-inch Hale telescope. The new observations possess twice the resolution of those obtained in 1962. The brightness temperature at the center of the disk appears to be nearly constant at 129°K. With some slight ambiguity, the light bands are about 0.5° cooler in appearance than the dark bands. There is some suggestion of morning-evening asymmetry in one of the bands. The Great Red Spot is found to be from 1.5° to 2.0° cooler than the surrounding disk at the newer resolution

Infrared photometric mapping of Venus through the 8- to 14-micron atmospheric window

The 200-inch Hale telescope has been used to obtain high-resolution maps, on four mornings juxtaposed about the Mariner 2 encounter, of the brightness temperature of Venus in the 8- to 14-micron wavelength interval. The resolution was about 1/30 of the disk of Venus. The signal-to-noise ratio was in excess of 100. The maps reveal (1) a general limb darkening, (2) a bilateral symmetry about the planet's orbital plane, (3) a very slight wedging of the contours as the only day-to-night effect, and (4) a transient temperature anomaly in the southern hemisphere

Hot Shadows of Jupiter

On the evenings of 26 October and 15 December 1962, while the disk of Jupiter was being scanned for thermal emission in the 8- to 14-micron wavelength region, a large enhancement was discovered in the emission from shadows cast on Jupiter by the Jovian satellites Ganymede and Europa. However, on the evening of 14 December 1964, the shadow of satellite Io was observed and no enhancement was detected. The effect is thus variable with time

Venus: A Map of Its Brightness Temperature

The 200-inch Hale telescope has been used to make high-resolution maps of the brightness temperature of Venus at wavelengths 8 to 14 microns. Resolution of about 1/30 of the disk reveals a general symmetry about the plane of the orbit, no daynight temperature effects, and a transient temperature anomaly in the southern hemisphere