Intensity of the infrared radiation from interstellar grains in the solar neighborhood

The expected intensity distribution of the infrared radiation in the solar neighborhood from the grain models of dirty ice, graphite and graphite core-dirty ice mantle has been calculated. It is found that the expected intensity from grain models at 100 agrees reasonably well with the observations of Hoffmann and Frederick.     

Atmospheres of extreme metal-deficient stars

Atmospheric models have been constructed for effective temperatures 4000°, 4500° and 5000° and for hydrogen-to-metal ratios of 1, 10², 10³ and 10⁴ times the solar values, and for surface gravities of 2×10⁴ and 2×10². The effect of metal deficiency on the atmospheric structure of these stars are studied.National Academy of Sciences, National Research Council Postdoctoral Research Associate.     

The detection of the 5577.3å line of [OI] in comets

The spectral synthesis of C ₂ Swan band sequence V = – 1 indicates the intensity of the forbidden green oxygen line of 5577.3 to be about 3 to 5% of the 6300 line. Therefore, it appears that the green line should be observable in high-resolution spectra of a bright comet. Festou and Feldman suggest red/green >/ 10 means a water parent origin.     

A new technique for estimating D-region effective recombination coefficients under different solar flare conditions

Under solar flare conditions, the intensity of the solar X-rays below 10 Å increases by several orders of magnitude, while the increase in intensity of H-L is small. Photo-ionization rates in the various wavelength bands in theXUV spectrum have been presented graphically as a function of altitude under quiet, M3, X4, and outstanding flare conditions to show the relative importance of solar X-rays below 10 Å in the height range between 50 and 90 km. Presuming the total time constant for recombination of the ions with electrons remains constant at each altitude under different flare conditions, one can obtain the effective recombination coefficient _eff under these conditions with a knowledge of the quiet time recombination coefficient, the production rate profiles and profiles. The importance of the ratio of negative ions to electrons below 70 km in lowering the effective electron loss rates has been highlighted.     

Equivalent width of molecular lines in stars

The expected equivalent widths of the individual rotational lines of the Lyman and Werner bands of the hydrogen molecule from the solar atmosphere have been calculated. These results are used to predict what one expects to observe with a specified wavelength bandpass. These are compared with the observation of Dupree and Reeves.