Engineering topics
Publications and source records attributed to Hiltner, W. A..
Spectroscopic and photometric observations indicate a physical association between the peculiar early-type emission-line stars HD 122669 and HD 122691. The latter has undergone a drastic change in the strength of its emission lines during the past twenty years. There is some indication that both stars vary with shorter time scales.
Photographic spectra of Cen X-3 show that the primary star has a spectral type near O6.5 with weak, variable emission at 4640 and 4686 A. No orbital motion of the emission or absorption lines is detected; for the latter the upper limit is about plus or minus 50 km/sec. Analysis of the available data indicates that the primary is a factor of 2-3 less massive than expected from normal evolutionary models while the X-ray source has a mass near 1.5 times the solar mass.
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Photographic spectral data are presented for Sanduleak 160, an SMC B-type supergiant with which the strong binary X-ray source SMC X-1 is identified. These data show several important features: (1) Emission is conspicuously present at 4686 A at phases 0.1-0.3 and 0.7-0.85 (where phase 0.0 denotes X-ray eclipse) and undetectable near phase 0.5; (2) the emission has a large amplitude in velocity approximately out of phase with the expected motion of the primary star; (3) the absorption spectrum does not show any detectable change in spectral type throughout the orbit. The basic parameters of the system are studied on the basis of the new data, and a mass of near 2 solar masses is computed for the X-ray object. The data also furnish a number of constraints for models of the system.
We have measured the wavelength dependence of the interstellar polarization curve with higher wavelength resolution than has generally been used before. Our data show structure which has been previously unknown, and which may have important implications with respect to the composition of the interstellar grains. It is similar in general form to structure predicted on the basis of a theoretical model designed by us to give a detailed match to the extinction structure.
Sco X-1 was monitored at optical and X-ray wavelengths from 1970 April 26 to 1970 May 21. The optical observations were made at six observatories around the world and the X-ray observations were made by the Vela satellites. There was a tendency for the object to show greater variability in X-ray when the object is optically bright. A discussion of the intensity histograms is presented for both the optical and X-ray observations. No evidence for optical or X-ray periodicity was detected.
Photographic spectra of Cen X-3 show that the primary star has a spectral type near 06.5 with weak, variable emission at wavelength 4640 and 4686. No orbital motion of the emission or absorption lines is detected; for the latter the upper limit is approximately + or - 50 km/s. Analysis of the available data indicates that the primary is a factor of 2-3 less massive than expected from normal evolutionary models while the X-ray source has a solar mass near 1.5.
The variability of Sanduleak 160, the proposed optical counterpart of SMC X-1, has been confirmed. It shows a double-peaked optical variation with the minimum at X-ray eclipse being the deeper. The cos 2 theta variation has a semiamplitude of 0.050 mag in the B filter, the cos theta variation has a semiamplitude of 0.025 mag, and there is a cos 3 theta variation of 0.012 mag semiamplitude. From an analysis of the optical photometry and X-ray eclipse duration the mass ratio is found to be 0.28, i = 79 deg, and P = 3.89206 days. On the assumption that the mass of Sk 160 is 20 solar masses, the mass of SMC X-1 is 5.6 solar masses.
The optical counterpart of Her X-1 was observed for B-magnitude on 34 nights between July 30 and October 10, 1972. The scatter in the light curve is about 0.5 mag and may be related to the 35-day cycle.-
The bluest of thee 1500 southern OB stars discovered during an extensive photometric (UBV) and spectroscopic (MK) study of galactic structure in the southern hemisphere is discussed. The spectrum of this strikingly peculiar star is completely dominated by lines of neutral and ionized helium, most of which are extremely Stark-broadened. The spectral type is 08, with V = 10.52, B-V = -0.31, and U-B = -1.17. The absolute magnitude is probably +3. Located in the plane of the Milky Way, the CPD 31 1701 is hot, very underluminous, and extremely helium-rich.
Spectroscopic and photometric observations were carried out for HD 77581, a B0.5 Ib star located in the error box of the X-ray source 2U 0900-40. HD 77581 is identified as spectroscopic binary with a provisional period of 7.0 days and a semiamplitude of 26 km/sec. The minimum mass of the secondary star is near 1.4 solar mass.
Photometric and plane polarimetric observations of the radio source Oj 287 have been made in the optical region. The photometric data show variations of 0.10 mag with a timescale of 6-7 days superposed on a total decrease of approximately 0.5 mag during February 1972. The polarimetric data, which exhibit a similar decrease in plane polarization during this same period, suggest the possibility of a periodicity with a timescale of the order of 30 days.
Sco X-1 optical spectroscopic and photometric observations, noting H alpha and H ion emission lines pattern-continuum brightness relationship
Scorpius X-1 X ray and optical variations observation by Vela 5 satellites
X ray sources identification with optical counterparts, noting lack of radio and pulsar type emissions
Simultaneous X ray and optical observations of Scorpius XR-1, comparing rocket data from various flights
Extrasolar X ray source optical observations, discussing identification method and individual characteristics