Engineering topics
Publications and source records attributed to Conti, P. S..
HD 47129 is a double-lined spectroscopic binary with a period 14.3961 days and a visual magnitude of V = 6.06. Using the Copernicus U2 spectrometer, observations were obtained of the system on eight occasions, starting March 2, 1977. Some results are presented and discussed.
Radial velocities are measured on coude spectrograms of over 200 O-type stars in both hemispheres. The selection of effective wavelengths for the stellar lines to be measured is reviewed, and the measured velocities are compared with those available in a catalog of O stars. The Trumpler (1935) effect (a reported anomalous redshift in certain O stars) is inconclusively reinvestigated, atmospheric motions in Of stars are examined, and some kinematic properties of O stars are discussed statistically. It is found that 58% of all O stars and 41% of all the Of stars considered are certain or probable binaries. A K-term in the range from 1 to 2 km/s is derived for the O stars, but the Of stars are shown to have a highly significant negative K-term. It is suggested that the systematically negative peculiar velocities of the Of stars are due to outflow of material beginning at the photospheric level.
Data from nine high-dispersion spectra of HDE 226868, the optical candidate for Cyg X-1, are presented. The line profiles at He II (4686 A) show marked changes from night to night. Our data are not compatible with models where the emission line arises from the unseen secondary component of the system, as has been suggested by other observers. We propose that the emission originates in a gas stream falling toward the secondary; this provides observational evidence that the X-ray source is powered by accretion. We also see changes in spectral type and luminosity class with phase, further complicating attempts to make mass estimates for the system.
The ratio of the visual luminosities of the O and WC components of the binary system gamma (2) Vel has been derived by comparison of the emission-line strengths in the spectrum with those in the spectrum of a single WC8 star, HD 192103. The result is 1.4 mag, with the O star being brighter; the classification of the O star was found to be 09 I, so that the classification of gamma (2) Vel is WC8+09 I.
Element abundances of sharp lined field early A stars using model atmosphere
Anomalously low Sc/Sr ratio in A zero stars of Pleiades cluster from model atmosphere abundance analysis
Model stellar atmosphere abundance analysis of eight sharp-line A stars in Pleiades