Epsilon Aurigae
A Mysterious Star System
Table of Contents

Dedication

Table of Contents

List of Tables and Figures

Preface

Acknowledgments

I. Introduction
1.1 Variable Stars
1.2 Auriga, Capella and the Kids
1.3 Epsilon Aurigae
1.4 Backyard Astronomers

II. History
2.1 First Observations
2.2 Disagreeable Spectra
2.3 Alternative Models
2.4 Observational Progress Preceding the 1982-84 Eclipse
2.5 The 1982-84 Eclipse and Theoretical Progress
2.6 Inter-eclipse Milestones on the Approach to 2009
2.7 References

III. 1982/1984 Campaign
3.1 The Campaign
3.2 American Astronomical Society Meeting
3.3 Workshop Invited Papers
3.4 Workshop Contributed Papers
3.5 Workshop Attendees
3.6 Workshop Photographs
3.7 Workshop Attendee Photograph
3.8 Photometry Data
3.8.1 Out-of-eclipse magnitudes
3.8.2 1982 -1984 Totality Magnitudes
3.8.3 1982 -1984 Depths Magnitudes
3.8.4 Contact Times
3.8.5 1982 -1984 Eclipse Summary of Event Durations
3.8.6 Photometry Data Plots
3.9 Spectroscopy
3.10 Polarimetry
3.10.1 Introduction
3.10.2 Interpretation
3.11 References

IV. Post 1984 Observations
4.0 Introduction
4.1 Photometry Data
4.1.1 HPO UBV Photometric Data 1982 - 1988
4.1.2 HPO UBV Photometric Data 2003 - 2008
4.1.3 HPO JH Photometric Data 2006 - 2007
4.1.4 Boyd UBV Photometric Data 1987 - 2005
4.1.5 Frequency Domain Data
4.1.5.1 Introduction
4.1.5.2 HPO V Band Frequency Domain Data
4.1.5.3 HPO V Band Prominent Period Data
4.2 Spectroscopy Data
4.2.1 Hydrogen Alpha Lines
4.2.2 Be Stars Ha Line
4.2.3 Epsilon Aurigae Ha Line
4.3 Polarimetry Data
4.4 Interferometry Data
4.4.1 Introduction
4.4.2 Navy Prototype Optical Interferometer
4.5 References

V. Current Interpretations
5.1 Epsilon Aurigae System Schematic
5.2 Next Eclipse Timing
5.3 Past Eclipse Timing
5.3.1 Timing Changes
5.3.1.1 Duration and Totality Change
5.3.1.2 Ingress and Egress Change
5.3.1.3 Eclipse Period Change
5.3.1.4 Eclipse Magnitude Change
5.3.2 Out-of-Eclipse Changes
5.3.2.1 Photometric Changes
5.3.2.2 Spectroscopic Changes
5.3.3 Summary and Predictions
5.4 References

VI. 2009 Campaign
6.1 Campaign Web Site
6.2 Photometry Contact Time Predictions
6.3 Spectroscopy 98 6.4 Polarimetry
6.5 Interferometry
6.5.1 Palomar Testbed Interferometer
6.5.2 Preliminary Results
6.6 References

VII. Similar Star Systems
7.1 Introduction
7.2 Zeta Aurigae
7.2.1 Introduction
7.2.2 Zeta Aurigae Data
7.2.3 Zeta Aurigae Comparison Star
7.2.4 HPO Zeta Aurigae Data
7.2.5 References
7.3 VV Cephei
7.3.1 Introduction
7.3.2 VV Cephei Data
7.3.3 VV Cephei Comparison Star
7.3.4 References
7.4 EE Cephei
7.4.1 Introduction
7.4.2 EE Cephei Data
7.4.3 EE Cephei Comparison Star
7.4.4 HPO EE Cephei Data
7.4.5 References
7.5 BM Orionis
7.5.1 Introduction
7.5.2 Theta 1 Orionis Data
7.5.3 BM Orionis Comparison Star
7.5.4 References

VIII. Prospects
8.1 Interferometry Diameter Measurements
8.2 Changing Eclipse Timings
8.3 Out-of-Eclipse Variations
8.4 Ha Emission Wing Variability
8.5 Polarimetry
8.6 Your Role

IX. Observational Methods
9.0 Magnitudes
9.1 Naked Eye Techniques
9.2 Photometry
9.2.1 Introduction
9.2.2 Photomultiplier Tubes
9.2.3 Solid State Detectors
9.2.4 Charge-Coupled Device (CCD) Detectors
9.2.5 Photometric Filters
9.2.6 Photometric Techniques
9.2.7 Photometry Equipment
9.2.7.1 Single Channel Photometry Equipment
9.2.7.1.1 PMT Based Photometers
9.2.7.1.1.1 HPO Photon Counter Photometer
9.2.7.1.1.2 Optec SSP-5 Analog Photometer
9.2.7.1.1.3 PMT Saturation
9.2.7.1.1.4 Dead Time
9.2.7.1.1.5 Threshold Adjustment
9.2.7.1.1.6 Photon Counting Data Reduction
9.2.7.1.2 Single Channel Solid State Photometers
9.2.7.1.2.1 Optec SSP-3 PIN Diode Photometer
9.2.7.1.2.1.2 Optec SSP-4 Infrared Photometer
9.2.7.2 Potential Problems
9.2.8 CCD Photometry
9.2.8.1 CCD Observing
9.2.8.1.1 AutoStar Software
9.2.8.1.2 CCD Photometry Technique
9.2.8.1.2.1 Darks
9.2.8.1.2.2 Exposure
9.2.8.1.2.3 Defocusing
9.2.8.1.2.4 Flat Fields
9.2.8.2 Image processing
9.2.8.2.1 AutoStar Image Processing
9.2.8.2.1.1 Differential Magnitude
9.2.7.2.1.2 Setting the Reference Magnitude
9.2.7.2.1.3 Raw Magnitude Determination
9.2.7.2.2 AIP4WIN Image Processing
9.2.9 Data Reduction
9.2.9.1 Star Information
9.2.9.2 Observatory and Equipment Information
9.2.9.3 Observation Data Entry
9.2.9.4 Final Data Reduction
9.2.10 Data Analysis
9.2.10.1 Plotting Data
9.2.10.2 Time Domain
9.2.10.3 Phase
9.2.10.4 Frequency Domain
9.2.10.4.1 Sine wave
9.2.10.4.2 Square Wave
9.2.10.4.3 Peranso
9.3 Spectroscopy
9.3.1 Introduction
9.3.2 Spectra
9.3.3 Types of Spectra
9.3.3.1 Continuous Spectra
9.3.3.2 Emission Spectra
9.3.3.3 Absorption Spectra
9.3.3.4 Stellar Spectroscopy
9.3.4 The Shape of a Spectral Line
9.3.4.1 Collisional Broadening
9.3.4.2 Doppler Broadening
9.3.4.3 Rotational Broadening
9.3.4.4 Zeeman Effect
9.3.4.5 Stark Effect
9.3.5 Stellar Spectra Classification
9.3.5.1 Spectral Type
9.3.5.2 Luminosity Classes
9.3.5.3 Chemical Composition
9.3.5.4 Radial Velocities
9.3.6 Spectroscopy Equipment
9.3.6.1 Introduction
9.3.6.2 Star Analyser 100
9.3.6.3 SBIG SGS
9.3.6.4 SBIG DSS-7
9.3.6.5 Shelyak Instruments Lhires III Spectrograph
9.3.7 Spectroscopy Techniques
9.3.7.1 Introduction
9.3.7.2 Obtaining a Spectrum
9.3.7.3 Spectroscopy Software
9.3.7.3 Planck's Law
9.3.7.4 Full Width Half Mean (FWHM)
9.3.7.4 Equivalent Width (EW)
9.3.7.5 Atmospheric Lines (Telluric Lines)
9.3.7.6 Spectral Resolution
9.3.7.7 Spectral Intensity
9.4 Polarimetry
9.4.1 Introduction
9.4.2 Polarimetry Techniques
9.5.3 Polarimetry Equipment
9.4.3 References
9.5 Interferometry
9.5.1 Introduction
9.5.2 Interferometry Techniques
9.5.3 Interferometry Equipment
9.5.4 References
9.6 Astronomical Dates
9.6.1 Julian Date
9.6.2 Heliocentric Julian Date
9.6.3 Modified, Reduced and Partial Julian Date
9.6.4 Julian Date List

Glossary

Meet the Authors

Index

List of Tables and Figures

Tables

II. History
Table 2.1 Model Comparison

III. 1982/1984 Campaign
Table 3.1 1982-84 Eclipse Contact Times
Table 3.2 1982-84 Eclipse Event Durations

IV. Post 1984 Observations
Table 4.1 HPO V Photometric Data Summary
Table 4.2 Boyd V Photometric Data Summary

V. Current Interpretations
Table 5.1 Past Eclipse Timing Summary

VI. 2009 Campaign
Table 6.1 Official Predicted Contact Times PJD + 2,450,000
Table 6.2 Unofficial Predicted First Contact Time For UBV Bands

VII. Similar Star Systems
Table 7.1 Zeta Aurigae Basic Data
Table 7.2 Zeta Aurigae Magnitudes Out-of-Eclipse
Table 7.3 Lambda Aurigae Magnitudes
Table 7.4 EE Cephei Magnitudes Out-of-Eclipse
Table 7.5 Star b Magnitudes
Table 7.6 Star c Magnitudes
Table 7.7 BM Ori Magnitudes Out-of-Eclipse
Table 7.8 Theta 1 Ori B Ori Magnitudes
Table 7.9 Theta 1 Ori C Ori Magnitudes
Table 7.10 Theta 1 Ori D Ori Magnitudes

IX. Observational Methods
Table 9.1 Sample SSP-4 Data
Table 9.2 Hydrogen Series
Table 9.3 MK of Spectral Types
Table 9.4 Luminosity Classes
Table 9.5 Lhires III Parameters
Table 9.6. Lhires III Performance

Figures

I. Introduction
Figure 1.1 Capella and the Kids

II. History
Figure 2.1 Shu-Shu Huang Model

III. 1982/1984 Campaign
Figure 3.1 Newsletter #5 Cover
Figure 3.2 AAS Tucson, Arizona Meeting Billing
Figure 3.3 AAS Poster Paper
Figure 3.4 Ronald Webbick Preparing Talk
Figure 3.5 Bruce Altner
Figure 3.6 Webbink and Stencel
Figure 3.7 F.B. Wood
Figure 3.8 D.S. Hall
Figure 3.9 R.E. Stencel Introducing a Speaker
Figure 3.10 J.L. Hopkins
Figure 3.11 Epsilon Aurigae Workshop Gang
Figure 3.12 Stig Ingvarsson TAO - Sweden
Figure 3.13 1982 -1984 U Band Data Plot
Figure 3.14 1982 -1984 B Band Data Plot
Figure 3.15 1982 -1984 V Band Data Plot
Figure 3.16 1982 -1984 (U - B) Data Plot
Figure 3.17 1982 -1984 (B - V) Data Plot
Figure 3.18 1982 -1984 (U - B) vs. (B -V) Data Plot
Figure 3.19 Kemp, 1985 Workshop Diagram

IV. Post 1984 Observations
Figure 4.1 HPO V Band Data 1982 - 1988
Figure 4.2 HPO B Band Data 1982 - 1988
Figure 4.3 HPO U Band Data 1982 - 1988
Figure 4.4 HPO V Band Data 2003 - 2008
Figure 4.5 HPO B Band Data 2003 - 2008
Figure 4.6 HPO U Band Data 2003 - 2008
Figure 4.7 2006 - 2007 Season HPO J Band Data
Figure 4.8 2006 - 2007 Season HPO H Band Data
Figure 4.9 Boyd V Band Data 1987 - 2005
Figure 4.10 Boyd B Band Data 1987 -2005
Figure 4.11 Boyd U Band Data 1987 - 2005
Figure 4.12 HPO V Frequency Domain 1984 - 1985
Figure 4.13 HPO V Frequency Domain 2003 - 2004
Figure 4.14 HPO V Frequency Domain 2003 - 2008
Figure 4.15 HPO V Frequency Domain 2007 - 2008
Figure 4.16 HPO V Prominent Periods 2003 - 2008
Figure 4.17 HPO V Prominent Periods 2003 - 2008
Figure 4.18 HPO V Prominent Periods 2003 - 2008
Figure 4.19 HPO V Prominent Periods 2007 - 2008
Figure 4.20 Sample Ha Spectrum
Figure 4.21 Be Star Hydrogen a Lines
Figure 4.22 Illustration of Hydrogen a Line Horns
Figure 4.23 Hydrogen a Line Parts
Figure 4.24a Epsilon Aurigae Ha Spectra 12 December 2005
Figure 4.24b Epsilon Aurigae Ha Spectra 24 November 2006
Figure 4.25 Epsilon Aurigae Primary Star Ring
Figure 4.26 Schematic of Epsilon Aurigae Primary Star
Figure 4.27 NPOI Flagstaff, Arizona

V. Current Interpretations
Figure 5.1 Epsilon Aurigae System Schematic
Figure 5.2 2009/2011 Eclipse Timing
Figure 5.3 Past Eclipse Duration and Totality Time Changes
Figure 5.4 Past Eclipse Ingress and Egress Time Changes
Figure 5.5 Eclipse Periods
Figure 5.6 Eclipse D Magnitudes

VI. 2009 Campaign
Figure 6.1 Palomar Observatory
Figure 6.2 Palomar Observatory and PTI Aerial View
Figure 6.3 PTI Aerial View Figure 6.4 Optical Delay Lines
Figure 6.5 FFT Image and Diffraction Pattern July 2009
Figure 6.6 FFT Image and Diffraction Pattern October 2009
Figure 6.7 FFT Image and Diffraction Pattern July 2010

VII. Similar Star Systems
Figure 7.1 Zeta Aurigae Image
Figure 7.2 U Band Plot of 1985 Zeta Aurigae Eclipse
Figure 7.3 VV Cephei System Diagram
Figure 7.4 HPO EE Cephei V Filter Image
Figure 7.5 EE Cephei Detail
Figure 7.6 Theta 1 Orionis Detail
Figure 7.7 Theta 1 Orionis HPO V Image
Figure 7.8 Eclipse of BM Orionis

IX. Observational Methods
Figure 9.1 The Stars of Aurigae
Figure 9.2 1P21 Photomultiplier Tube
Figure 9.3 PMT Pulse Forming Voltage Divider
Figure 9.4 PMT Spectral Response
Figure 9.5 HPO Photon Counting Photometer
Figure 9.6 HPO Photometer on C-8
Figure 9.7 Inside HPO Photometer
Figure 9.8 UBVRI Band Passes
Figure 9.9 Photometric UBVRIYJHK Filter Bands
Figure 9.10 HPO C-8 UBV Photon Counting System
Figure 9.11 Optec PMT Analog SSP-5 System
Figure 9.12 Optec SSP-3 Photometer
Figure 9.13 Optec SSP-4 Photometer
Figure 9.14 HPO 12" LX200 GPS and SSP-4
Figure 9.15 SSP-4 Detector Comparison
Figure 9.16 FMP JH Band Summary Data
Figure 9.17 DSI Pro/Mogg Adapter/Camera Lens
Figure 9.18 HPO Wide Angle BVRI Photometry
Figure 9.19 AutoStar Histogram Figure
9.20 AutoStar Photometry Cursor
Figure 9.21 Setting Reference Magnitude
Figure 9.22 Setting Aperture and Annulus Diameters
Figure 9.23 Selecting Determine Magnitude
Figure 9.24 Determine Max Pixel and Total Flux
Figure 9.25 AIP4WIN Initial Display
Figure 9.26 Single Image Photometry Window
Figure 9.27 AIP4WIN Aperture and Annulus Settings
Figure 9.28 AIP4WIN Photometry Results
Figure 9.29 AIP4WIN Photometry Results Detail
Figure 9.30 Phase Plot
Figure 9.31 Frequency Domain Plot
Figure 9.32 100 Hz Sine Wave
Figure 9.33 100 Hz Square Wave
Figure 9.34 Peranso V Data
Figure 9.35 DFT Frequency Domain
Figure 9.36 Prominent Periods
Figure 9.37 p/o Hydrogen Transition Series
Figure 9.38 Hydrogen Balmer Spectrum
Figure 9.39 Star Analyser 100
Figure 9.40 Star Analyser Spectra
Figure 9.41 SBIG SGS Spectrograph
Figure 9.42 SBIG DSS-7 Spectrograph
Figure 9.43 Spectrum of Nova Scorpii-2
Figure 9.44 Lhires III Spectrograph
Figure 9.45 Inside the Lhires III Spectrograph
Figure 9.46 Lhires III with DSI Pro CCD Cameras
Figure 9.47 Lhires III on 12" LX200 GPS
Figure 9.48 Black Body Spectrum
Figure 9.49 Full Width Half Mean
Figure 9.50 Equivalent Width
Figure 9.51 Equivalent Widths of Hydrogen a
Figure 9.52 Atmospheric (Telluric) Lines
Figure 9.53 Electromagnetic Spectrum
Figure 9.54 Polarized Light
Figure 9.55 Astronomical Polarimeter
Figure 9.56 Optical Interferometer
Figure 9.57 Mt. Wilson Interferometer
Figure 9.58 Mt. Wilson Interferometer Detail