Interior Modelling of Massive Stars in Multiple Systems (Springer Theses)

✍ Scribed by Cole Johnston

• Publisher: Springer
• Year: 2021
• Tongue: English
• Leaves: 210
• Category: Library

✦ Synopsis

This thesis by Cole Johnston brings novel insights into the inner workings of young massive stars. By bridging the observational fields of binary stars and asteroseismology this thesis uses state of the art statistical techniques to scrutinise theories of modern stellar astrophysics. Developing upon the commonly used isochrone fitting methodology, the author introduces the idea of isochrone cloud fitting in order to account for the full breadth of physics observed in stars. The author combines this methodology with gravity mode asteroseismic analysis to asses the level of chemical mixing deep within the stellar core in order to determine the star‘s age and core mass. Wrapped into a robust statistical framework to account for correlations, this methodology is employed to analyse individual stars, multiple systems, and clusters alike to demonstrate that chemical mixing has dramatic impact on stellar structure and evolution.

✦ Table of Contents

Supervisor’s Foreword
Preface
Acknowledgements
Contents
Acronyms
1 Scientific Context
1.1 Introduction
1.2 Stellar Structure
1.2.1 Energy Transport
1.2.2 Brunt–Vaïsälä Frequency
1.2.3 Relevant Time Scales
1.3 Internal Chemical Mixing Processes
1.3.1 Convective Boundary Mixing
1.3.2 Radiative Envelope Mixing
1.3.3 Overall Internal Mixing Profile
1.4 Standard Stellar Evolution of Intermediate- to High-Mass Stars
1.4.1 Stellar Evolution with Enhanced Internal Mixing
1.5 Asteroseismology
1.5.1 Stellar Oscillations
1.5.2 Types of Pulsating Stars
1.6 Multiple Stellar Systems
1.6.1 Binary Stars
1.6.2 Stellar Clusters
1.7 The Mass Discrepancy
References
2 Stellar Evolution Tracks, Isochrones, and Isochrone-Clouds
2.1 Stellar Structure and Evolution Tracks
2.1.1 Initial Models and Numerical Controls
2.1.2 Internal Mixing Processes
2.1.3 Input Physics
2.1.4 Fixed Parameters
2.1.5 Convective Core Mass
2.1.6 Computational Requirements
2.2 Isochrone Construction
2.2.1 Definition
2.2.2 Construction
2.2.3 Isochrone Fitting
2.3 Isochrone-Cloud Construction
2.3.1 Definition
2.4 Forward Modelling Scheme
2.4.1 Mahalanobis Distance
2.4.2 Error Estimation
2.4.3 Markov Chain Monte Carlo
2.5 Summary
References
3 The O+B Eclipsing Binary HD 165246
3.1 Introductory Remarks
3.2 Spectroscopic Analysis
3.2.1 Line Profile Variability
3.2.2 Interpretation as Variable Macroturbulence
3.2.3 Updated Atmospheric Solution
3.3 Photometric Analysis
3.3.1 K2 Photometry
3.3.2 Updated Binary Model
3.3.3 Photometric Variability
3.4 Discussion
3.5 Summary
References
4 Estimating the Convective Core Mass for Stars in Eclipsing Binaries
4.1 Introductory Remarks
4.2 Target Overviews
4.2.1 CW Cephei
4.2.2 U Ophiuchi
4.3 Data
4.3.1 New Spectroscopy and Disentangling
4.3.2 Archival Photometry
4.4 Modelling
4.4.1 Spectroscopic Disentangling and Atmospheric Modelling
4.4.2 PHOEBE Models
4.4.3 CW Cep
4.4.4 U Oph
4.4.5 Comparison of Results
4.5 Evolutionary Modelling
4.5.1 Modelling Results and Discussion
4.5.2 Rotation and Tides
4.6 Interpretation
4.7 Expanded Sample
4.8 Summary
References
5 Binary Asteroseismology
5.1 Introduction
5.2 Stellar Models and Modelling Setup
5.2.1 Stellar Models
5.2.2 Asteroseismic Diagnostic
5.2.3 Parameter Estimation
5.2.4 Hare-and-Hound
5.3 Kepler Sample
5.3.1 KIC 4930889
5.3.2 KIC 6352430
5.3.3 KIC 10080943
5.4 Discussion
5.5 Summary
References
6 The Effect of Enhanced Core Masses on the Observed Morphology of Young Clusters
6.1 Introducing the Extended Main-Sequence Turn-off in Young Massive Clusters
6.2 Modelling Setup
6.3 Application to NGC 1850 and NGC 884
6.3.1 NGC 1850
6.3.2 NGC 884
6.4 Discussion and Conclusions
References
7 Towards Constraining Tidal Mixing: U Gru
7.1 Introduction
7.2 U Gru
7.2.1 TESS Light Curve
7.2.2 UVES Observations
7.3 Pulsational Characteristics
7.4 Interpretation
7.5 Summary and Conclusions
References
8 Final Remarks
8.1 Summary
8.2 Current and Future Prospects for the Precise Modelling of Pulsating …
8.2.1 Individual Targets
8.3 Towards a Generalised Sample and Ensemble Modelling
References
Appendix A Base MESA Inlist
Appendix B Moment Method Periodograms
Reference
Appendix C Marginalised Posterior Distributions for Chap.4摥映數爠eflinkch:chaptersps0444
Appendix D Secondary Component Parameter Correlation Plots From Chap. 5摥映數爠eflinkch:chaptersps0555
Index