This dissertation has been microfilmed exactly as received 68-3028 MEISEL, David Dering, 1940- A STUDY OF MULTIPLE STAR SYSTEMS INVOLVING COMPONENTS OF SPECIAL A ST RO PHY SICA L INTEREST. The Ohio State University, Ph.D., 1967 Astronomy University Microfilms, Inc., Ann Arbor, Michigan A STUDY OF MULTIPLE STAR SYSTEMS INVOLVING. COMPONENTS OF SPECIAL ASTROPHYSICAL INTEREST DISSERTATION Presented in Partial Fulfillment of the Requirements for the Degree Doctor of Philosophy in the Graduate School of The Ohio State University By David. Dering Meisel, B.S., M.S. The Ohio State University 1967 Approved by Adviser Department of Astronomy ACKNOWLEDGMENTS I would like to thank Dr. Arne Slettebak, Dr. George Collins, and Dr. Phillip Keenan of the Perkins Observatory Staff for their suggestions, comments and patience during all phases of this work. Also I would like to thank Dr. Walter Mitchell for the loan of the Gerber GOAT in order to complete the microphotometer reduction. Also I would thank Dr. Carlos and Mercedes Jaschek for reading the manuscript, particularly the notes to Table 6, and for their valuable comments. The help of a number of other people and institutions is also grate­ fully acknowledged; in particular, Father F. J. Heyden at Georgetown College Observatory for time on their microphotometer, Ted Fay and Dr. Holis Johnson for the radial velocity reduction program and three runs on the Indiana University CDC computer, and the staff of the University of Virginia Computer Science Center for generous support. I would, like to thank my colleagues at the Leander McCormick Obser­ vatory for suggestions and their aid of telescope time and equipment with­ out which the photometry could not have been completed. I am grateful to Dr. Collins of the Perkins Observatory and Dr. H. John Wood of the McCormick staff for providing results especially for this work and in advance of their own publications. Travel and telescope time on the Perkins telescope and equipment at Flagstaff and Columbus provided by the Ohio State and Ohio Wesleyan Uni­ versities is gratefully acknowledged. VITA March 28, 19^0 Born - Fairmont, West Virginia 1961 B.S., West Virginia University, Morgantown, West Virginia 1962-1963 Teaching Assistant, Department of Astronomy The Ohio State University, Columbus, Ohio I963 M.S., The Ohio State University, Columbus, Ohio 1963-1965 Perkins Observatory Assistant, Department of Astronomy, The Ohio State University, Columbus, Ohio 1965-1967 Instructor, Department of Astronomy University of Virginia, Charlottesville, Virginia FIELDS OF STUDY Major Field: Astronomy Studies in Physics. Professors 0. Rex Ford and Charles N. Thomas Studies in Cometary Astronomy. Professor Nicholas T. Bobrovnikoff Studies in Astrophysics. Professor Arne Slettebak iii TABLE OF CONTENTS page ACKNOWLEDGEMENTS ............................................ ii VITA ......................■................................. iii TABLE OF C O N T E N T S .......................................... iv LIST OF TABL E S............ v LIST OF ILLUSTRATIONS...................................... vi Chapter I. INTRODUCTION .................................... 1 Chapter II. THE OBSERVATIONS ............................ 13 Chapter III. THE RESULTS AND DI S C U S S I O N ..................... 6l Chapter IV. SUMMARY AND CONCLUSIONS ........................ 84 BIBLIOGRAPHY................................................ 8 7 iv LIST OF TABLES Table page 1. List of S t a r s .......................................... 5 2. Index Catalogue ........................................ 8 3. V Sin i, Spectral Classification Standards . 19 Photoelectric D a t a .......... 29 5. Indices and Equivalent W i d t h s ............................ 33 6. Spectral Types and Rotational Velocities ............... 37 7. H-gamma Values for C o m p a n i o n s ............................ 56 8. Absolute Magnitude Calibration ........................ 62 9. Absolute Mlagnitudes from Hydrogen Li n e s ................... 68 10. Mean Deviations of Calibrated AbsoluteMagnitudes .... 71 11. Mean Rotational Velocities .............................. 75 12. Statistical Correlation Data ................ ..... 79 v LIST OF ILLUSTRATIONS , Figure page 1. Correlations Between Spectral Types ...................... 22 2. Correlation Between Luminosity Classes .................. 23 3. Magnitude Difference Residuals ............................ 23 4. Correlations of Rotational Velocities .................... 24 5. Correlation Between Magnitude Differences ............... 25 6. Correlation Between Equivalent Widths ................... 26 7. H-R Diagram for Early-type Stars ........................ 66 8. H-R Diagram for Late-type S t a r s .......................... 67 9. Correlation Between Absolute Magnitudes ................. 73 10. Rotational Velocity Means for Class V .................... 76 11. Rotational Velocity Means for Classes IV, III ............ 76 12. Rotational Velocity Means for Be S t a r s .............. 76 Chart 1. S Monocerotis System .................................... 12 2. HD 15238-9 S y s t e m ........................................ 12 3. HD 190918 12 vi CHAPTER I INTRODUCTION Wide visual multiple stars, unlike close binaries, afford an opportunity to examine, in detail, the astrophysical properties of two or more stars which presumably were formed in the same neighborhood of space and under similar conditions of composition, density, and mean angular momentum, but have evolved independently. Since the formation of physical systems by close encounters between stars of widely different ages is very improbable, the assumption is usually made that the compo­ nents of all systems showing common dynamical properties, have similar ages. Thus visual multiple star systems might be used to study stellar evolution and rotation with techniques similar to those that have been successful with star clusters. In the study of visual binary systems, however, the apparent proximity of the components and the possibility of mere optical connection present difficulty in both observation and inter­ pretation. In the closer visual binaries, the existence of an orbit is sufficient to establish dynamical connection, but the observational diffi­ culties are more severe. For wide pairs, the observational problems are not as great, but the establishment of dynamical connection becomes more difficult. In spite of the observational and dynamical difficulties, astrophy­ sical investigations of visual double and multiple stars have been carried out by Leonard (1923), Johnson (1953), Wallenquist (195^,1958), Struve and Franklin (1955), Struve, Franklin, and Stableford (1955), Opolsky (1956), 2 Bakos and Oke (1957). Bidelman (1958), Bakos (1959), Hopmann (1959), Stephenson (I960), Wallerstein and Westfall (i960), Berger (1962), Slette- bak (1963), Cester (1963), Eggen (1963, 1965), Tolbert (1964), Petrie and Batten (1966) and others. In the study described here, the visual double stars involving 0 and B-type stars, supergiants, and Be stars constituted the primary groups of interest. In addition, pairs having other characteristics of interest were included for the observing program. A master list of some 1200 pairs was compiled by cross-referencing the Index Catalogue of Double Stars 1961.0 (ICDS) (H. M. Jeffers, W. H. van den Bos, and F. M. Greeby, 1963) with the special lists given below. (It is hoped to publish a revised and extended version of the master list at a later date. No attempt was made to differentiate between optical and physical pairs.) OB stars - Morgan, Code, and Whitford (1955)• Supergiants - Johnson and Morgan (1953); Wilson (19^1); Bidelman (1957a, 1957b). Be stars - Merrill and Burwell (1933, 19^3, 19^9). Bp and Ap stars - Bertaud (1959, I960). WR and Ce stars - Roberts (1962); Stephenson (1965). Variable stars - Kukarkin, Paranago, et. al. (1958-1964); Plaut (193^, 1939); Hertzsprung (1922); Baize (1962); Perova (1964). Eclipsing binaries - Koch, Sobieski and Wood (1963); Tchudovitchov (1951). Spectroscopic binaries - Moore (1936); Moore and Neubauer (1948); Koritnikov, Laurov, and Martinov (196I-I963). High velocity stars - Roman (1955)• Composite spectra - Hynek (1938). 3 The systems given initial consideration were selected by taking observational difficulties such as limiting magnitude, separation, orien­ tation, and declination into account. During the actual observing periods, OB stars, supergiants, and Be stars were given the highest priority while stars having composite spectra were considered to have the lowest priority. A total of 66 systems was studied. Using interstellar line intensities, H-gamma equivalent widths, radial velocities, and proper motions (where available), sixteen of these were considered to be optical and were re­ jected for further study. The main purposes of the present study are: 1) calibration of the absolute magnitudes of specific components, especially those exhibiting interesting or peculiar astrophysical characteristics; 2) investigation of the axial rotation characteristics of the visual components; 3) empirical investigation of the effects of rotation on the cali­ brated luminosities, Balmer-line measurements, and spectral types for the sample of stars available. The astrophysical data obtained from moderate dispersion spectra and photoelectric photometry were: 1) spectral types and luminosity classes on the M system; 2) rotational velocities (V sin i) using both eye-estimates and line half-intensity-widths; 3) photoelectric ^mv values for a number of