A few tens au scale physical and chemical structures around young low-mass protostars / / Yoko Oya

• Record Nr.: UNINA9910629285203321
• Autore: Oya Yoko
• Pubbl/distr/stampa: Singapore : , : Springer, , [2022]; ©2022
• ISBN: 9789811917080; 9789811917073
• Descrizione fisica: 1 online resource (219 pages)
• Collana: Springer Theses
• Disciplina: 810
• Soggetti: Protostars
• Lingua di pubblicazione: Inglese
• Formato: Materiale a stampa
• Livello bibliografico: Monografia
• Nota di bibliografia: Includes bibliographical references.
• Nota di contenuto: Intro -- Supervisor's Foreword -- Preface -- Acknowledgements -- Contents -- 1 Introduction -- 1.1 Formation of Low-Mass (Solar-Type) Stars -- 1.2 Radio Astronomy -- 1.3 Astrochemistry in Star-Forming Region -- 1.3.1 1980s: Astrochemistry in High- and Low-Mass Star-Forming Region -- 1.3.2 1990s: Chemical Composition at a 103 au Scale -- 1.3.3 2000s: Chemical Diversity at a 102-103 au Scale -- 1.3.4 2010s: ALMA Era at 10-102 au Scale -- 1.4 Motivation for This Research -- 1.5 Outline of This Thesis -- References -- 2 ALMA Observation -- 2.1 Principles of Interferometers -- 2.1.1 Coordinate System -- 2.1.2 Correlation Function and Cross Power Spectrum -- 2.1.3 Visibility -- 2.2 ALMA -- 2.2.1 ALMA Site -- 2.2.2 Antennas -- 2.2.3 Receivers -- 2.2.4 Backends -- 2.3 Observations with Interferometers -- 2.3.1 Calibration -- 2.3.2 Observed Intensity Distribution -- 2.3.3 CLEAN Method -- References -- 3 Model Calculation -- 3.1 Introduction -- 3.2 Infalling-Rotating Envelope Model -- 3.2.1 Configuration of the Infalling-Rotating Envelope Model -- 3.2.2 Infalling-Rotating Envelope Model with Various Physical Parameters -- 3.3 Keplerian Model -- 3.4 Outflow Model -- 3.5 Physical Parameters of the Models -- 3.6 Examples of the Model Analysis -- 3.6.1 The L1527 Case -- 3.6.2 The TMC-1A Case -- 3.6.3 Some Caveats for the Model -- References -- 4 L1527 -- 4.1 Introduction -- 4.2 Results -- 4.2.1 Overall Distribution -- 4.2.2 ; Envelope -- 4.2.3 Outflow -- 4.3 Discussion -- 4.3.1 Direction of the Outflow -- 4.3.2 Angular Momentum -- References -- 5 IRAS 15398-3359 -- 5.1 Introduction -- 5.2 Observations -- 5.3 Results -- 5.3.1 Overall Distribution of H2CO and CCH -- 5.3.2 Outflow -- 5.3.3 Protostellar Envelope -- 5.3.4 Comparison with an Envelope Model -- 5.4 Discussion -- References -- 6 IRAS 16293-2422 Source A -- 6.1 Introduction -- 6.2 Observation Data.; 6.3 Molecular Line Distribution -- 6.4 Velocity Structure -- 6.4.1 OCS -- 6.4.2 CH3OH and HCOOCH3 -- 6.4.3 H2CS -- 6.5 Infalling-Rotating Envelope Model -- 6.5.1 OCS -- 6.5.2 CH3OH and HCOOCH3 -- 6.5.3 H2CS -- 6.6 Discussion -- 6.6.1 Infalling-Rotating Envelope and Its Centrifugal Barrier -- 6.6.2 Origin of the Chemical Change Around the Centrifugal Barrier -- 6.6.3 Gas Kinetic Temperatures of H2CS -- 6.6.4 Abundance of HCOOCH3 Relative to CH3OH -- 6.7 Summary of This Chapter -- References -- 7 IRAS 16293-2422 Source B -- 7.1 Introduction -- 7.2 Observation -- 7.3 Distribution -- 7.4 Kinematic Structure -- 7.4.1 Observed Features -- 7.4.2 Comparison of Molecular Distribution with the Source A Case -- 7.5 Modelling -- 7.5.1 Infalling-Rotating Envelope Model -- 7.5.2 Origin of the Inverse P-Cygni Profile -- 7.6 Outflow -- 7.7 Gas Kinetic Temperature -- 7.8 Abundance of Metafont Relative to CH3OH -- 7.9 Summary of This Chapter -- References -- 8 L483 -- 8.1 Introduction -- 8.2 Observation -- 8.3 Distribution -- 8.4 Kinematic Structure -- 8.4.1 Geometrical Configuration -- 8.4.2 CS -- 8.4.3 SO and HNCO -- 8.4.4 NH2CHO and Metafont -- 8.5 Analysis with the Models for the Disk/Envelope System -- 8.6 Outflow Structure -- 8.6.1 Outflow Cavity Wall Traced by CS -- 8.6.2 Comparison with the Outflow Model -- 8.6.3 Rotation Motion in the Outflow -- 8.6.4 SiO Emission -- 8.7 Chemical Composition -- 8.8 Summary of This Chapter -- References -- 9 Chemical Differentiation -- 9.1 Chemical Diversity -- 9.1.1 Chemical Diversity in a Disk Forming Region -- 9.1.2 Which Kind of the Chemical Characteristics is Common? -- 9.2 Chemical Change -- 9.2.1 Drastic Chemical Change Around the Centrifugal Barrier -- 9.2.2 Tracers in WCCC and Hot Corino Sources -- References -- 10 Physical Diversity -- 10.1 Evolution from Envelopes to Disks.; 10.2 Angular Momentum of the Envelope Gas -- 10.3 Relation Between the Envelope and the Outflow -- 10.4 Evolution of Outflows -- 10.4.1 Comparison Between L1527 and IRAS 15398-3359 -- 10.4.2 Relation to Dynamical Ages -- References -- 11 Conclusion -- 11.1 Summary of This Thesis -- 11.2 Future Prospects -- 11.2.1 Transition Zone from the Envelope to the Disk -- 11.2.2 How about in More Evolved Sources? -- 11.2.3 Chemical Heritage: Importance of Sulfur Chemistry -- References -- Appendix A Desorption Temperature -- A.1 Balance of the Adsorption and the Desorption -- Appendix Curriculum Vitae.