Doppler Method for the Detection of Extrasolar Planets

Description

The Doppler method is a key instrument in exoplanet detection, covering a wide range of techniques and expertise: high-resolution stellar spectroscopy, time series analysis, and periodic signal detection within non-Gaussian noise. This book provides a deep understanding of the Doppler method, including how to achieve a high RV measurement precision, as well as the challenges, limitations, and potential of the technique. It also covers other aspects of the method such instrumentation, wavelength calibration, finding periodic signals in RV time series, signal interpretation, and Keplerian orbits. It is an essential reference for researchers and graduate students in the field of exoplanets, and additionally stellar spectroscopists and instrumentalists. PRELIMS.pdf Preface Acknowledgments Author biography A. P. Hatzes CH001.pdf Chapter 1 Introduction 1.1 The Dawn of Doppler Measurements 1.2 Early Work on Stellar Radial Velocity Measurements 1.3 Toward Precise Stellar Radial Velocity Measurements 1.4 The Early Hints of Exoplanets 1.5 The 51 Peg Revolution 1.6 The Doppler Method References CH002.pdf Chapter 2 The Instruments for Doppler Measurements 2.1 Echelle Spectrographs 2.1.1 Gratings 2.1.2 Cross-dispersers 2.1.3 Dispersion and Spectral Resolution 2.1.4 The Blaze Function 2.1.5 Scattered Light 2.2 Fourier Transform Spectrometers 2.3 Charge-coupled Device Detectors 2.3.1 The Structure and Operation of a CCD 2.3.2 Quantum Efficiency 2.3.3 Bias Level 2.3.4 Gain 2.3.5 Readout Noise and Dark Current 2.3.6 Charge Transfer Efficiency 2.3.7 Linearity 2.3.8 Flat Fielding 2.3.9 Saturation and Blooming 2.3.10 Fringing 2.3.11 Persistence References CH003.pdf Chapter 3 Factors Influencing the Radial Velocity Measurement 3.1 Instrumental Characteristics 3.1.1 Wavelength Coverage 3.1.2 Signal-to-noise Ratio 3.1.3 Resolving Power 3.2 Stellar Characteristics 3.2.1 Stellar Rotational Velocity 3.2.2 Spectral Line Strength 3.2.3 Number Density of Spectral Lines 3.3 RV Precision across Spectral Types 3.3.1 Radial Velocities of High-mass Stars 3.3.2 Radial Velocities of Low-mass Stars References CH004.pdf Chapter 4 Simultaneous Wavelength Calibration 4.1 Instrumental Shifts 4.2 Hollow Cathode Lamps 4.2.1 Th–Ar 4.2.2 HCL in the Infrared 4.3 The Telluric Method 4.4 Gas Absorption Cells 4.4.1 The Hydrogen Fluoride Cell 4.4.2 The Iodine Absorption Cell 4.4.3 Absorption Cells at Infrared Wavelengths 4.5 Laser Frequency Combs 4.6 Fabry–Pérot Etalons 4.7 The RV Precision of Modern Spectrographs References CH005.pdf Chapter 5 Calculating the Doppler Shifts: The Cross-correlation Method 5.1 Mathematical Formalism 5.2 Choice of Template 5.2.1 Standard Stars 5.2.2 Synthetic Masks 5.2.3 Self-templates 5.2.4 Mismatched Template and Stellar Spectra 5.3 CCF Detection of Spectroscopic Binaries 5.4 Fahlman–Glaspey Shift Detection References CH006.pdf Chapter 6 The Iodine Cell Method 6.1 The Instrumental Profile 6.2 Modeling the IP with the Iodine Cell Method 6.3 Influence of Changes in the IP 6.4 Ingredients for the Iodine Cell Method 6.4.1 The Fiducial 6.4.2 The Template 6.5 Calculation of the Doppler Shift 6.6 Construction of an Iodine Cell 6.7 Closing Remarks References CH007.pdf Chapter 7 Frequency Analysis of Time Series Data 7.1 Introduction 7.2 The Discrete Fourier Transform 7.2.1 Convolution 7.2.2 Visualizing Fourier Transforms 7.3 The Lomb–Scargle Periodogram 7.4 The Generalized Lomb–Scargle Periodogram 7.5 The Bayesian Generalized Lomb–Scargle Periodogram 7.6 Comparison of the Types of Periodograms 7.7 The Spectral Window 7.8 The Nyquist Frequency and Aliasing 7.9 Frequency Resolution 7.10 Assessing the Statistical Significance 7.10.1 Using the Lomb–Scargle Periodogram 7.10.2 Using the Fourier Amplitude Spectrum 7.10.3 Bootstrap Randomization 7.11 Finding Multiperiodic Signals in Your Data 7.12 Required Number of Observations 7.13 Frequency versus Period References CH008.pdf Chapter 8 Keplerian Orbits 8.1 Orbital Parameters 8.2 Describing the Orbital Motion 8.3 The Radial Velocity Curve 8.4 The Mass Function 8.5 Mean Orbital Inclination 8.6 Eccentric Orbits 8.6.1 Observing Biases Caused by Eccentric Orbits 8.6.2 Eccentric Orbits in the Fourier Domain 8.6.3 Keplerian Periodograms 8.7 Calculating Keplerian Orbits 8.7.1 Transiting Planets 8.8 Dynamical Effects 8.8.1 Dynamical Stability 8.8.2 Planet Interactions 8.9 Barycentric Corrections References CH009.pdf Chapter 9 Avoiding False Planets: Rotational Modulation 9.1 Introduction 9.2 Spots 9.3 Plage and Faculae 9.4 Granulation and Convective Blueshift 9.4.1 The Sun Viewed as a Star 9.4.2 Velocity Spots 9.5 Testing for Rotational Modulation 9.5.1 Determining the Rotation Period of the Star 9.5.2 Evolution of Statistical Significance 9.5.3 Amplitude Variations References CH010.pdf Chapter 10 Avoiding False Planets: Indicators of Stellar Activity 10.1 Activity Indicators 10.1.1 Ca II H & K 10.1.2 Hα 10.1.3 Na D 10.1.4 TiO Bands 10.1.5 Hydroxyl 1.563 μm Absorption 10.2 Line Depth Ratios 10.3 Spectral Line Shapes 10.3.1 Line Bisectors 10.3.2 Line Widths 10.4 Chromatic RV Variations 10.5 Use of Individual Lines 10.5.1 Radial Velocities 10.5.2 Convective Blueshifts versus Line Strength 10.6 Radial Velocity Jitter 10.6.1 RV Jitter and Orbit Fitting 10.6.2 Sources of Jitter 10.6.3 Stellar Oscillations 10.6.4 Activity Jitter 10.7 Activity Cycles 10.8 Concluding Remarks References CH011.pdf Chapter 11 Dealing with Stellar Activity 11.1 Fourier Filtering 11.1.1 The Pitfalls of Prewhitening 11.2 High Pass Filtering 11.2.1 Local Trend Fitting 11.2.2 Floating Chunk Offset 11.3 Gaussian Processes 11.4 A Short Comparison of Filtering Methods 11.5 The RV Challenge 11.6 Toward Earth Analogs References CH012.pdf Chapter 12 Contributions to the Error Budget 12.1 Guiding Errors 12.2 Changes in the Instrumental Setup 12.3 Detector Errors 12.3.1 Electronic Noise Pickup 12.3.2 CCD Inhomogeneities and Discontinuities 12.3.3 Charge Transfer Effects 12.4 Errors in the Barycentric Correction 12.4.1 Inaccurate Time of Observations 12.4.2 Inaccurate Telescope Coordinates 12.4.3 Inaccurate Stellar Positions 12.4.4 Differential Barycentric Motion 12.5 The Secular Acceleration 12.6 Telluric Line Contamination 12.7 Moonlight Contamination References CH013.pdf Chapter 13 The Rossiter–McLaughlin Effect 13.1 Introduction 13.2 Origin of the Rossiter–McLaughlin Effect 13.3 The Rossiter–McLaughlin Effect in Exoplanets 13.3.1 The Radial Velocity Amplitude 13.3.2 The Spin–Orbit Alignment 13.4 Spin Axis of the Star References