Publications of the Astronomical Society of the Pacific

Eggen, O. J.

doi: 10.1088/129772Apmid: N/A

Pilachowski, C. A.; Bonsack, W. K.

doi: 10.1086/129747pmid: N/A

Line-blocking coefficients were measured from coude spectrograms covering the blue and green parts of the spectra, throughout the 9d3 cycle of HR 5355. The coefficient for the V band of the uvby photometry is found to vary through a range of 0" 06 of the continuum in a double wave, with maxima corresponding to the maxima of both the Eu ii and the Cr spectrum variation, which occur in antiphase. This line blocking cannot account for the strong single-wave light variation in the V band, which has a minimum at rare-earth maximum, but may be responsible, by redistribution of flux, for the double-wave character of the b- and y-band light variations. There is little variation of line blocking in the b and y bands. Line blocking varies significantly with wavelength and with phase in the vicinity of 5200 A, and is partially responsible for the minimum in the apparent continuum found by photometric observers. It does not appear to be possible to interpret the basic light variations of HR 5355 by the mechanisms recently proposed for this and other Ap stars. Key words: peculiar A stars - line blocking - spectrum variation - light variation

Wolff, S. C.; Morrison, N. D.

doi: 10.1086/129748pmid: N/A

Four-color (uvhy) photoelectric observations are presented for six Ap stars. No variations were found for the Hg-Mn star K Cue. The periods of 1d4450 for 45 Leo and 2d8881 for HR 5597 found by Wiuzer (1974) are confirmed. The period of HR 5153 is shown to be 2d451 Possible explanations for the photometric variations of 56 Ari and HR 4369 are discussed. Key words: photometry - peculiar A-type stars

Batten, A. H.; Fletcher, J. M.

doi: 10.1086/129749pmid: N/A

Radial velocities of beta Lyr are determined from spectrograms obtained at Victoria, Canada, from 1966 to 1974. Individual stellar velocities and phases are calculated, and the radial velocities are found to be well satisfied by an assumed circular orbit with a systemic velocity of about -17.8 km/sec and a velocity of 184.0 km/sec for the primary component, provided that account is taken of the changing period in calculating the phases and the velocity measurements are made only from the Si II lines. Previous reports indicating variations in the value of the systemic velocity are discussed, and it is shown that the reported variations may be due to the use of unreliable spectral lines for velocity measurement, small systematic differences between spectrographs, and possible occasional distortion of the velocity curve.

Hutchings, J. B.

doi: 10.1086/129750pmid: N/A

New coud6 spectrograms of the OB binary HD 163181 are analyzed. An absorption spectrum attributed to the secondary is reported for the first time, and it is deduced that the secondary is more massive and less luminous than the supergiant primary. The primary shows phase-dependent mass-loss characteristics and the present light curve suggests that it is near its Roche limiting radius. Nitrogen and oxygen abundances are unusual in the primary spectrum. The nature of the secondary is discussed. Key words: binaries - early-type stars - emission-line stars - mass loss

Holden, F.

doi: 10.1086/129751pmid: N/A

Key words: visual double stars - measures

Bolton, C. T.; Wicks, G.; Jones, R. B.; Young, A.

doi: 10.1086/129752pmid: N/A

New spectroscopic observations of the K giant HD 107325 from three observatories are reported. These observations, which extend from 1970 February to 1974 June, rule out the large-amplitude velocity variations of one-half day period that were reported by Fehrenbach, but suggest that a small-amplitude long-period velocity variation is present. The old observations are rediscussed. Key words: spectroscopic binary - radial veolcities

Landolt, A. U.

doi: 10.1086/129753pmid: N/A

VRI photometric observations of V 1017 Sgr in 1973 and 1974 are discussed. Key words: recurrent novae - photometry

Jacobsen, T. S.; Wallerstein, G.

doi: 10.1086/129754pmid: N/A

New velocities for the emission lines in R Aqr show that the system has not followed the orbit with a period of 26.7 years tentatively suggested by Merrill. The binary nature of the star and its enormous mass function of 16.5 solar masses are probably unreal. Evidence for mass loss with ionization and velocity increasing outward is presented.

Linnell, A. P.; Hill, S. J.; Brandt, E. F.

doi: 10.1086/129755pmid: N/A

An automated photometry system for use in optical astronomy is described which includes a minicomputer, a 24-inch Cassegrain reflector, an automated sequential photometer, a photomultiplier, and a programmable integrator. Design objectives and considerations are discussed, the system operation and hardware configuration are outlined, and the system software is described. Results are reported for tests to investigate the repeatability of integrator readings with a constant current calibrator connected to the input and the maximum rate of consecutive observations of a given source. It is noted that this system requires no computer language programming by the observer, integration times of less than 0.5 sec should not be used unless reduced accuracy is acceptable, and twelve UBV sets of observations of one source can be recorded in 2 min 15 sec.