INSTITUTE OF THEORETICAL PHYSICS AND ASTRONOMY, VILNIUS UNIVERSITY Vygandas Laugalys YOUNG STARS AND INTERSTELLAR EXTINCTION IN THE NORTH AMERICA AND PELICAN NEBULAE Doctoral dissertation Physical sciences, physics (02 P), astronomy, space research, cosmic chemistry (P 520) Vilnius, 2009 Disertacija rengta 1995 - 2009 metais Vilniaus universiteto Teorin˙es fizikos ir astronomijos institute Disertacija ginama eksternu Mokslinis konsultantas prof.habil.dr. V. Straiˇzys (Vilniaus universiteto Teorin˙es fizikos ir astronomijos institutas, fiziniai mokslai, fizika – 02 P) VILNIAUS UNIVERSITETO TEORINES˙ FIZIKOS IR ASTRONOMIJOS INSTITUTAS Vygandas Laugalys JAUNOS ZVAIGˇ ZˇES˙ IR TARPZVAIGˇ ZDINˇ E˙ EKSTINKCIJA SIAURˇ ES˙ AMERIKOS IR PELIKANO DEBESYSE Daktaro disertacija Fiziniai mokslai, fizika (02 P), astronomija, erdv˙es tyrimai, kosmin˙echemija (P 520) Vilnius, 2009 Contents PUBLICATION ON THE SUBJECT OF THE DISSERTATION . 5 1. INTRODUCTION 9 1.1. Galactic structure in the investigated direction . ............. 9 1.2. The North America and Pelican Nebulae . ..... 10 1.3.YoungStars .................................... 10 1.4.TheIonizingSource(s) . ... 10 1.5.OpenClusters ................................... 11 2. OBSERVATIONAL DATA AND REDUCTIONS 12 2.1. Wide Field CCD Observations with the Maksutov telescope.......... 12 2.1.1.ObservedTargets ............................. 12 2.1.2.Reductions ................................. 13 2.1.3. The Catalogand Classification ofStars . ..... 13 2.2. CCD Observations with the Flagstaff telescope . ......... 14 2.2.1.Introduction ................................ 14 2.2.2. Advanced M 67 Flatfield Corrections . .... 14 2.2.3. Comparison With Other Photometric Data . .... 16 2.2.4.Conclusions................................. 24 2.2.5. Observed Targets and Data Reductions: NGC 6997 . ...... 30 2.2.6. Observed Targets and Data Reducions: The Dark Cloud L 935 .... 30 2.2.7. Observed Targets and Data Reducions: Collinder 428 . ........ 31 2.2.8. Classification of Stars and Their Color Excesses, Extinctions and Dis- tances ................................... 31 2.3. Zero-Age Main Sequence in the Vilnius System................. 33 2.3.1.Introduction ................................ 33 2.3.2. Photometry of the Hyades, Pleiades, Praesepe and Orion OB1 in the Vilnius System .............................. 33 2.3.3. Absolute Magnitude vs. Color Diagram . .... 34 3. DUST AND MOLECULAR CLOUDS 36 3.1. InterstellarExtinctionLaw . ...... 36 3.1.1.Introduction ................................ 36 3.1.2.Near-UVandOptical ........................... 37 3.1.3.NGC6997Area .............................. 39 3.1.4. 2MASS Data in the North America and Pelican Area and Cyg OB2 Association ................................ 42 3.2.InterstellarExtinction . ...... 50 3.2.1.Introduction ................................ 50 3.2.2. Relatively Transparent NAP Areas . .... 50 3.2.3.TheRegionofNGC6997 . .. .. 53 3.2.4.L935DarkCloudArea .......................... 55 3.2.5.TheRegionofCollinder428 . 58 3.2.6. Extinctionfrom2MASSstarcounts . ... 59 3 4. YOUNG STARS AND IONIZING SOURCES 60 4.1. Suspected Emission-Line and T Tauri Type Stars . ......... 60 4.2.IonizingSources ................................ .. 62 4.2.1.Introduction ................................ 62 4.2.2. TheComer´on&PasqualiStar . 63 4.2.3. More O-Like StarsBehind The L935Cloud . ... 63 4.2.4.TheI-Jvs.J-HDiagram . .. .. 65 4.2.5. SpectralEnergyDistributions. ..... 69 4.2.6. CommentsonIndividualStars . .. 69 4.2.7.Conclusions................................. 71 5. OBSERVED OPEN CLUSTERS 72 5.1.NGC6997 ..................................... 72 5.2.Collinder428................................... 74 6. THE MAIN RESULTS AND CONCLUSIONS 76 6.1. SUMMARY OF THE MAIN RESULTS . 76 6.2.CONCLUSIONS.................................. 77 REFERENCES 78 ACKNOWLEDGMENTS 83 APPENDIX 84 Table2.2.4........................................ 84 Table2.2.5........................................ 90 Table2.2.6........................................ 91 Table2.2.7........................................ 92 Table2.2.8........................................ 94 Table2.2.9........................................ 95 Table2.3.1........................................ 103 Table2.3.2........................................ 105 Table2.3.3........................................ 105 Table3.1.5........................................ 106 Table3.2.1........................................ 109 Table3.2.2........................................ 110 Table3.2.3........................................ 112 Table3.2.4........................................ 113 4 PUBLICATION ON THE SUBJECT OF THE DISSERTATION 1. Straiˇzys V., Corbally C. J., Laugalys V. 1999, ”Interstellar Extinction Law in the Vicinity of the North America and Pelican Nebulae”, Baltic Astronomy, 8, 355 2. Laugalys V., Straiˇzys V. 2002, ”CCD Photometry and Classification of Stars in the North America and Pelican Nebulae Region. I. Mol˙etai Photometry”, Baltic Astronomy, 11, 205 3. Laugalys V., Kazlauskas A., Boyle R. P., Vrba F.J., Philip A. G. D. Straiˇzys V. 2004, ”CCD Photometry of the M67 Cluster in the Vilnius System. II. New Photometry of High Accuracy”, Baltic Astronomy, 13, 1 4. Laugalys V., Straiˇzys V., Vrba F.J., Boyle R. P., Philip A.G.D. Kazlauskas A. 2006, ”CCD Photometry and Classification of Stars in the North America and Pelican Nebulae Region. II. The Region of NGC6997”, Baltic Astronomy, 15, 327 5. Laugalys V., Straiˇzys V., Vrba F.J., Boyle R. P., Philip A.G.D. Kazlauskas A. 2006, ”CCD Photometry and Classification of Stars in the North America and Pelican Nebulae Region. III. The Dark Cloud L935”, Baltic Astronomy, 15, 483 6. Kazlauskas A., Straiˇzys V., Bartaˇsi¯ut˙eS., Laugalys V., Cernisˇ K., Boyle R. P., Philip A.G.D. 2006, ”Zero-age Main Sequence in the HR Diagram of the Vilnius Photometric System”, Baltic Astronomy, 15, 511 7. Laugalys V., Straiˇzys V., Vrba F.J., Cernisˇ K., Kazlauskas A., Boyle R. P., Philip A.G.D. 2007, ”CCD Photometry and Classification of Stars in the North America and Pelican Nebulae Region. IV. The Region of a Supposed Cluster Collinder 428”, Baltic Astronomy, 16, 349 8. Straiˇzys V., Corbally C. J., Laugalys V. 2008, ”2MASS Two-color Interstellar Redden- ing Line in the Direction of the North America and Pelican Nebulae and the Cyg OB2 Association”, Baltic Astronomy, 17, 125 9. Straiˇzys V., Laugalys V. 2008, ”O-like Stars in the Direction of the North America and Pelican Nebulae”, Baltic Astronomy, 17, 143 10. Straiˇzys V., Laugalys V. 2008, ”2MASS Two-color Interstellar Reddening Lines in the Inner Galaxy”, Baltic Astronomy, 17, 253 CONTRIBUTION RELATED TO THE DISSERTATION AT THE INTERNATIONAL CONFERENCES 1. Laugalys V. ”Vilnius, 2MASS and IRAS data together”, in Str¨omvil workshop, Poland, Krakow 2008 September 11 2. Laugalys V. ”An Experience with Aperture and PSF Reductions of CCD Exposures from Flagstaff”, in Str¨omvil workshop, Lithuania, Mol˙etai 2006. August 28 - September 09 3. Boyle R. P., Janusz R., Philip A. G. D. , Laugalys V., Kazlauskas A. ”CCD Flatfielding for Str¨omvil Photometry in M 67”, in American Astronomical Society Meeting 207, # 29.06; Bulletin of the American Astronomical Society, Vol. 37, p.1212, 2005 4. Boyle R. P., Janusz R., Philip A. G. D. , Laugalys V. ”Automation and Iteration Methods for Processing CCD Stellar Photometry in the Str¨omvil System”, in American Astronom- ical Society Meeting 205, # 153.02; Bulletin of the American Astronomical Society, Vol. 36, p.1602, 2004 5. Straiˇzys V., Zdanaviˇcius J., Zdanaviˇcius K., Laugalys V., Kazlauskas A., Cernisˇ K., Boyle R. P., Philip A. G. D. 2004, ”Interstellar extinction in the MBM 12 molecular cloud area in Aries”, American Astronomical Society Meeting 205, # 59.04; Bulletin of the American Astronomical Society, Vol. 36, p.1439, 2004 6. Laugalys V., Boyle R.P., Kazlauskas A., Vrba F. J., Philip A. G. D. , Straiˇzys V. , ”Ac- curacy of CCD photometry: open cluster M67” in Dynamical and Chemical Evolution of Galactic Star Clusters, Taiwan, Chung-Li, National Central University, 2003 November 24-28 7. Laugalys V., Boyle R. P., Kazlauskas A., Vrba F.J., Philip A. G. D. Straiˇzys V. ”Large- Scale Errors in CCD Photometry of M67” in Stellar Photometry: Past, Present and Future, Lithuania, Vilnius 2003 September 17-20 5 8. Boyle R. P., Janusz R., Philip A. G. D. , Kazlauskas A., Laugalys V. ”Flatfielding Errors in Stromvil CCD Photometry” in Stellar Photometry: Past, Present and Future, Lithuania, Vilnius 2003 September 17-20 9. Boyle R. P., Janusz R., Laugalys V., Philip A. G. D. ”CCD Flatfield Correction by Dif- ferential Stellar Photometry: Automated Methods”, in American Astronomical Society Meeting 203, # 04.02; Bulletin of the American Astronomical Society, Vol. 35, p.1207, 2003 10. Boyle R. P., Laugalys V., Philip A. G. D. ”Flatfield Correction by Differential CCD Photometry in M67”, in American Astronomical Society, 201, # 91.09; Bulletin of the American Astronomical Society, Vol. 34, p.1257, 2002 11. Corbally C., Straiˇzys V., Laugalys V. ”Interstellar Extinction Law in the Vicinity of the North America and Pelican Nebulae”, in American Astronomical Society, 195, # 74.01; Bulletin of the American Astronomical Society, Vol. 31, p.1478, 1999 6 The main aim of the dissertation The main aim of this work was a comprehensive photometric investigation of the Milky Way region at Galactic longitudes around l=83◦–87◦ in the direction of the North America and Pelican nebulae in order to get distances, absorbing properties of the dust