This dissertation has been microfilmed exactly as received 69-11,654 IANNA, Philip Anthony, 1938- AN ASTROMETRIC AND SPECTROSCOPIC STUDY OF THE GALACTIC CLUSTER NGC 1039. The Ohio State University, Ph.D., 1968 Astronomy University Microfilms, Inc., Ann Arbor, Michigan AN ASTBOXETRIC AND SPECTROSCOPIC STUDY OF THE GALACTIC CLUSTER NGC 1039 DISSERTATION Presented in Partial Fulfillment of the Requirements for the Degree Doctor of Philosophy in the Graduate School of The Ohio State University By Philip Anthony Ianna, B.A., N.A, ******* The Ohio State University 1968 Approved by Adviser Department of Astronoiqy PLEASE NOTE: Appendix pages are not original copy. Print is indistinct on many pages. Filmed in the best possible way. UNIVERSITY MICROFILMS. ACKNOWLEDGEMENTS I am grateful to many people at a number of institutions for their kind assistance throughout this study. I would particularly like to thank try adviser. Dr. George W. Collins,11, for his encouragement and guidance over a rather long period of time. Also at The Ohio State University Drs. Walter E. Kitchell, Jr. and Arne Slettebak have given useful advice in several of the observational aspects of this work. Travel and telescope time provided by the Ohio State and Ohio Wesleyan Universities is gratefully acknowledged. The astrometric plate material was made available to me through the kind generosity of Dr. Peter van de Xamp, Director of the Sproul Observatory, and Dr. Nicholas S. Wagman, Director of the Allegheny Observatory. Other members of the staff at the Allegheny Observatory were most helpful during two observing sessions there. I am indebted to Dr. Kaj Aa. Strand, Scientific Director, The U. S. Naval Observatory, for the opportunity to measure the astrometric plates on their automatic measuring engine, and to Dr. Victor Blanco, I'ir.'R. Kip Riddle, and other members of the Naval Observatory staff for assistance while the measurements were being made. The major portion of the computing for this investigation has been carried out through very generous grants of computing time from The Ohio State University Computer Center. Kr. Edwin R. Lassettre of the Computer Center has also been very generous with his time in giving ii help in numerous ways. I am also indebted to the Center for Advanced Studies of the University of Virginia for aid with computing time and support during the final stages of this work. The staff of the Leander McCormick Observatory has given further aid by making available telescope time and equipment with which to do the photoelectric photometry. I am grateful for a N. D. E. A. Fellowship which provided financial assistance for one year. iii ; \ VITA May 27, 1938 B o m - Philadelphia, Pennsylvania I960 B.A., Swarthmore College, Swarthmore, Pennsylvania 1960-1962 Research Assistant, Department of Astronomy, Swarthmore College, Swarthmore, Pennsylvania 1962 M.A., Swarthmore College, Swarthmore, Pennsylvania 1962-1965 Teaching Assistant, Department of Astronomy. The Ohio State University, Columbus, Ohio 1965-I966 N.D.E.A. Fellow, Department of Astronomy. The Ohio State University, Columbus, Ohio 1966-1967 Teaching Assistant, Department of Astronomy, The Ohio State University, Columbus, Ohio 1968 Research Associate, The Center for Advanced Studies in the Sciences, The University of Virginia, Charlottesville, Virginia PUBLICATIONS "Aberrations and Field Errors of the Sproul 24-inch Objective." Astron. J., 6£, 273. 1962 "A Flare of T Ccronae Borealis." Astrophys. J., 139. 780, 1964 "On Aberrations and Field Errors." Vistas in Astronomy, 6 , 93, 1965 iv TABLE OF CONTENTS Page ACKNOWLEDGEMENTS ............................................... ii VITA ........................................ iv LIST OF TABLES ................................................ vii LIST OF ILLUSTRATIONS ......................................... ix CHAPTER I. INTRODUCTION .............. 1 II. SPECTROSCOPIC OBSERVATIONS IN NGC 1039................... 7 Spectral Classification ........................... 10 Rotational Velocities ........... 11 The Radial Velocities .............. 13 Radial Velocity of NGC 1039 ....................... 20 H I . PHOTOMETRY IN THE REGION OF NGC 1039 ................... 25 The Photoelectric Photometry ................... 26 The Iris Photometry ........... 31 Accuracy of the Magnitudes ........................ 38 IV. ANALYSIS OF ASTROMETRIC INSTRUMENTATION ................ 4-1 Characteristics of the Sproul 2^-inch Refractor .... hZ The Thaw 30-inch Refractor..... ................... ^6 The U.S. Naval Observatory Astrometric Refractor .... 5^ The U.S. Naval Observatory Automatic Measuring Engine ...................... 5^ V. THE PROPER MOTION REDUCTIONS ........................... 66 The Observations ................ 66 Plate Measurement and Data Editing......... 66 Rigorous Plate Reduction Methods............. 71 Choice of Plate Model .................... 76 Formation of Normal Equations for the Full Solution................................ 80 Solution of Normal Equations from Complete Data Set . 83 v CHAPTER Pago Plato-Pair Reductions ............................. 86 VI. ANALYSIS OF THE PROPER LOTIONS ......................... 93 Comparison of Sproul, Allegheny, and Dieckvoss Proper Lotions ............................... 93 Reduction to Absoluto Lotions .................. 101 Cluster Lembership .................. 102 Cluster Color Lagnitude Diagram and Distance Lodulus ....................................... 107 Space Lotion of NGC 1039 .......................... 109 Further Discussion of Ap Stars in NGC 1039 ....... Ill APPENDIX ..................................................... 115 LIST OF REFERENCES ........................................... 1^9 vi LIST OF TABLES Table Page 1. Summary of Galactic Cluster Internal Proper Motion Studies 3 2. Radial Velocity Table 8 3. Rotational Velocity Standards 12 Lines Utilized in Radial Velocity Determinations of B-A Stars 16 5. Lines Utilized in Radial Velocity Determinations of F Stars 16 6 . Spectroscopic Results for the Brighter Stars in NGC 1039 17 7. Mean Error of a Radial Velocity from One Spectrogram 19 8 . Stars Rejected from Cluster Membership on the Basis of Radial Velocity 21 9. Radial Velocities of A-Stars Common to Wilson’s General Catalog 23 10. Calibration of Rakos D. C. Amplifier 28 11 Fan Mountain Photoelectric Photometry for NGC 1039 29 12. Fan Mountain Photometry - Extinction and Color Coefficients 29 13. NGC 1039 - Photoelectric Standards for Iris Photometry 33 14. Observational Data for Photometric Plates of NGC 1039 35 15. Johnson - Dieckvoss Visual Magnitudes 39 16. Ianna - Dieckvoss Visual Magnitude Fainter than 11.0 40 17. Sproul 24-inch Refractor Chronology 43 18. Thaw 30”inch Refractor Chronology 47 19. Observing Data for Thaw Hartmann: Tests 50 20. Constants of the Thaw Objective 53 vii Table page 21. Calibration of Mann Engine 422D54 56 22. Measured Separations and Setting Error of the KRI Engine as a. Function of Image Size 60 23. Plate Variances and Proper Motions from Direct and Direct- Reverse Measurements 6l 24. Variances from Reduction of Direct against Reverse Measurements of a Plate 63 25. Observational Data-Astrometric Plate Material 67 26. Sproul Plate Variances for Various Plate Constant Material 77 27. Allegheny Plate Variances for Various Plate Constant Models 79 28. Sproul Plate-Fairs 87 29. Allegheny Plate-Pairs 87 30* Sproul Reference Stars in NGC 1039 88 31. Allegheny Reference Stars in NGC 1039 89 32. Average Internal Mean Error of a Proper Motion for a Single Plate-Fair 92 33. Linear Correction Constants to Adjust Allegheny to Sproul Proper Motions 100 34. P-eduction of Relative Proper .Motions to the System of the FX3 102 35. Color Excess of Brighter Members of NGC 1039 109 36. Summary of Data on Peculiar A-Stars in UGC 1039 112 I LIST OF ILLUSTRATIONS Figure Page 1. Transmission Curves of the Fan Fountain U3V Filters 27 2. Determination of Color and Extinction Coefficients 32 3. A Comparison between Visual Magnitudes from Inverted Least-Squares Solutions 37 4. Sproul Zonal-Focus Curves 45 5. Recent Sproul Hartmann Test Results 45 6 . Thaw Hartmann Test Results 51 7. Magnitude Dependence of Residuals from Sproul Plates 246-23703 62 8 . Magnitude Dependence of Residuals from Sproul Plates 246 and 38703 64 9. Proper Motion Differences vs. Color in X 94 10. Proper Motion Differences vs. Color in Y 95 11. Proper Motion Differences in X vs. X 97 12. Proper Motion Differences in Y vs. Y 9° 13. Proper Motion Differences with Common Reference Stars 99 14. Proper Motion Diagram-3proul Motions 104 15. Proper Motion Diagram-Allegheny Motions 105 16. Proper Motion Diagram-Combined Motions 106 17. Color-Magnitude Array, NGC 1039 108 ix CHAPTER I INTRODUCTION The segregation of cluster members from the stellar background is of vital importance to investigations of galactic clusters. The criteria of highest validity are a common distance or a common motion of the stars in question. Few clusters are close enough to allow an accurate direct distance determination, so one must measure proper motions or radial velocities in order to adjudge the presence of common motions. The proper motion criterion has been most frequently used. In this century we find some 120 astrometric studies of galactic clusters, 40# carried out between 1950 and 1959. that account for only about 10# of the known clusters owing to some duplication. Regrettably the desired degree of reliability is not attained in the bulk of these studies (Vasilevskis 1962). There are a variety of reasons for this.