Engineering topics

Kumar, C. K.

Publications and source records attributed to Kumar, C. K..

4 records

NASA NTRS1993

Remote measurement of planetary magnetic fields by the Hanle effect

Resonance fluorescence lines in the spectra of planetary atmospheres are polarized. They will be depolarized by magnetic fields in the scattering medium (Hanle effect). The amount of depolarization was calculated for some atomic (FeI, CaI) lines and some molecular lines (NO gamma bands) seen in the Earth's day glow spectra. The results are presented and the potential advantages of LIDAR measurements for obtaining atmospheric magnetic fields are discussed. The depolarization of Na and Ca lines are suitable for measuring magnetic fields in and near Io.

Kumar, C. K.↗

NASA NTRS1986

Diffuse interstellar bands in low color excess stars. III

Measurements of the equivalent widths of the diffuse interstellar bands at 6284 A and 6613 A in the spectra of 23 stars with E(B-V) less than 0.1 mag are reported. The band strengths do not correlate with interstellar H2 column density. They are probably produced by molecular mantles on grains or very stable molecules such as the polycyclic aromatic hydrocarbons.

Kumar, C. K.↗

NASA NTRS1983

A search for X-rays from runaway stars

Enhanced X-ray emission from an early-type runaway star would be direct evidence for the presence of a collapsed companion, and thus for its origin as the result of a supernova explosion in a massive binary. To test this idea, measurements of X-ray fluxes in the 0.5-3 keV energy range from nine O and B type runaway stars were made with the Einstein Observatory. In each case, the X-ray luminosity observed does not exceed that expected from a normal OB star. Therefore we conclude that, if the runaway stars have collapsed companions, the separations of the components must be much greater than those in normal OB binaries.

Kumar, C. K.↗

NASA NTRS1980

OH and NH emission studies of comet Kohoutek

A 30 inch flat mirror was used with the solar telescope of the Kitt Peak National Observatory to obtain the integrated disc spectrum of the Sun between the wavelengths of 3000A and 4000A at a resolution of about two hundred thousand. The data obtained were used to calculate the intensities of the fluorescent lines of the OH radical in comets. The results were compared with those obtained using the center of the disc spectrum only. The wavelength of the reference point and the dispersion from which the wavelength of other points can be obtained are presented in tabular form.

Kumar, C. K.↗