Publications of the Astronomical Society of the Pacific

Whitelock, Patricia A.

doi: 10.1086/132019pmid: N/A

This paper concerns interacting binary systems involving Mira variables. Twenty-six objects which potentially fall into this category are identified and observations of them covering the spectral regions from X-ray to radio are reviewed. Particular emphasis is given to near-infrared observations which are pertinent to establishing the presence of a Mira variable and also to new far-infrared data from IRAS. The majority of the objects under consideration have been classified as symbiotic stars. They are closely related to the well-known binary, o Cet, which might be described as 'mildly' symbiotic. It is shown how the knowledge of normal Miras can contribute to the understanding of the evolutionary condition and luminosities of these binary Miras. Distances are derived for those objects with measured pulsation periods. The significance of the relatively long pulsation periods shown by these objects is also discussed.

Phillips, M. M.; Phillips, A. C.; Heathcote, S. R.; Blanco, V. M.; Geisler, D.; Hamilton, D.; Suntzeff, N. B.; Jablonski, F. J.; Steiner, J. E.; Cowley, A. P.; Schmidtke, P.; Wyckoff, S.; Hutchings, J. B.; Tonry, J.; Strauss, M. A.; Thorstensen, J. R.; Honey, W.; Maza, J.; Ruiz, M. T.; Landolt, A. U.; Uomoto, A.; Rich, R. M.; Grindlay, J. E.; Cohn, H.; Smith, H. A.; Lutz, J. H.; Lavery, R. J.; Saha, A.

Liller, William; Mayer, Ben

doi: 10.1086/132021pmid: N/A

The ongoing PROBLICOM program in the Southern Hemisphere now makes it possible to derive a reliable value for the overall production rate of Galactic novae. The result, 73±24 y-1, indicates that the Galaxy outproduces M31 by a factor of two or three. The authors estimate that the rate of supernova ejecta is one and a half orders of magnitude greater than that of novae in the Galaxy.

Welch, D. L.; Evans, N. R.; Lyons, R. W.; Harris, H. C.; Barnes, T. G.; Slovak, M. H.; Moffett, T. J.

doi: 10.1086/132022pmid: N/A

A total of 62 new radial-velocity observations of the classical Cepheid U Aql have been obtained during the interval 1969 - 86. The authors present the first determination of a spectroscopic binary orbit for this star. The orbital elements derived from both new and published velocities are given. IUE observations reported by Böhm-Vitense and Proffitt (1985) indicate the presence of an early-type main-sequence companion. The orbital elements combined with estimates of the companion mass result in upper limits for the mass of the Cepheid in the range 6.4 - 8.8 Msun;. The possibility of spatially resolving the system using interferometric techniques is discussed.

Sahade, Jorge; Garcia, Lia G.

doi: 10.1086/132023pmid: N/A

The ultraviolet spectrum of the system Mu1 Scorpii at two phases of the orbital cycle is described. The presence of resonance lines of Si IV and C IV suggests that there are nonthermal sources in the system. The spectrum displays absorption lines that appear to follow the orbital motion of either component. The spectrum also displays sharp absorption features of which some, at least, must arise in the interstellar medium and part of which, perhaps, in the very outer layers of the circumbinary envelope. The presence of wind in the system is suggested by the spectrum. The cooler component of the system is definitely a B star of later spectral type than the B1.5V object, with a linewidth that suggests a luminosity certainly not higher than that of a main-sequence star. The ultraviolet continuous spectrum is that of a B1.5V star.

Poli, A. A.; Bord, D. J.; Cowley, C. R.

doi: 10.1086/132024pmid: N/A

An element identification study has been performed on the sharp-lined Si star HD 43819 using the method of wavelength-coincidence statistics (WCS). The results are compared to a study by Adelman (1985) who used traditional methods. The data generally confirm the previous investigation but also provide evidence to support the identifications of Dy III, Gd II, Nd III, and Mo II.

Keenan, Philip C.; Yorka, Sandra B.; Wilson, Olin C.

doi: 10.1086/132025pmid: N/A

Fifty of the stars designated as super-metal-rich by Spinrad and Taylor (1969) are classified here on the Revised MK System. Positive CN indices are assigned in recognition of the characteristic excesses of carbon and nitrogen in their atmospheres, as compared to normal Population I stars. For only a few of the stars, an abnormal strength of the iron lines or of Ca 4226 A is so noticeable that they need to be distinguished by positive indices for these metals.

Clementini, G.

doi: 10.1086/132026pmid: N/A

A photoelectric BVRI sequence of eleven stars homogeneously covering the field of the Galactic globular cluster NGC 6121 (M4) is presented using data acquired in the Cousins BVRI photometric system. Three of the stars in the sequence are also on the list of Alcaino and Liller (1984), and a comparison is made with their data. This photometric sequence can be used in the calibration of future observations of NGC 6121 with other detectors.

Bessell, M. S.; Weis, E. W.

doi: 10.1086/132027pmid: N/A

Cubic transformations have been derived between colors measured in the Cousins and the Kron systems using measurements of common stars with spectral types from A0 V to M6 V. Polynomial fits are also derived for the mean main sequence for late-type dwarfs.

Alexander, A. L.; Joner, M. D.; McNamara, D. H.

doi: 10.1086/132028pmid: N/A

Photometric observations of the prototype variable BL Her are described. The reddening, metallicity, temperature, and surface gravity of the star are determined. A Baade-Wesselink analysis is made to determine the radius and distance to the variable. The mass of the star is determined to be 0.75 solar, placing it in the range of RR Lyrae variables. The metallicity of +0.20, however, is greater than that of any known RR Lyrae variable.