BỘ GIÁO DỤC VÀ ĐÀO TẠO VIỆN HÀN LÂM KHOA HỌC VÀ CÔNG NGHỆ VIỆT NAM HỌC VIỆN KHOA HỌC VÀ CÔNG NGHỆ ----------------------------- ĐỖ THỊ HOÀI Tên đề tài: NGHIÊN CỨU LỚP VỎ CỦA CÁC SAO KHỔNG LỒ ĐỎ Ở BƯỚC SÓNG VÔ TUYẾN LUẬN ÁN TIẾN SỸ VẬT LÝ HÀ NỘI – 2017 BỘ GIÁO DỤC VÀ ĐÀO TẠO VIỆN HÀN LÂM KHOA HỌC VÀ CÔNG NGHỆ VIỆT NAM HỌC VIỆN KHOA HỌC VÀ CÔNG NGHỆ ----------------------------- ĐỖ THỊ HOÀI Tên đề tài: NGHIÊN CỨU LỚP VỎ CỦA CÁC SAO KHỔNG LỒ ĐỎ Ở BƯỚC SÓNG VÔ TUYẾN LUẬN ÁN TIẾN SỸ VẬT LÝ Chuyên ngành: Vật lý nguyên tử Mã số: 62 44 01 06 Người hướng dẫn khoa học: 1. Pierre Darriulat, Trung tâm Vũ trụ Việt Nam 2. Thibaut Le Bertre, Đài thiên văn Paris Hà Nội – 2017 MINISTRY OF SCIENCE AND VIETNAM ACADEMY OF TECHNOLOGY SCIENCE AND TECHNOLOGY GRADUATE UNIVERSITY OF SCIENCE AND TECHNOLOGY ----------------------------- DO THI HOAI Thesis title: STUDY AT RADIO WAVELENGTHS OF CIRCUMSTELLAR ENVELOPES AROUND RED GIANTS A THESIS IN PHYSICS HANOI – 2017 MINISTRY OF SCIENCE AND VIETNAM ACADEMY OF TECHNOLOGY SCIENCE AND TECHNOLOGY GRADUATE UNIVERSITY OF SCIENCE AND TECHNOLOGY ----------------------------- DO THI HOAI Thesis title: STUDY AT RADIO WAVELENGTHS OF CIRCUMSTELLAR ENVELOPES AROUND RED GIANTS A THESIS IN PHYSICS Major: Atomic physics Code: 62 44 01 06 Supervisors: 1. Pierre Darriulat, Vietnam National Space Center 2.
Thibaut Le Bertre, LERMA/Paris Observatory Hà Nội – 2017 Lời cam đoan Tôi xin cam đoan luận án này à công trình nghiên cứu của tôi thực hiện trong thời gian làm nghiên cứu sinhtại Viện Vật lý (Hà Nội) và Đài thiên văn Paris (Pháp). Kết quả nghiên cứu ở chương 3, chương 4, chương 5, chương 6 và chương 7 là công trình nghiên cứu của tôi cùng với các thầy hướng dẫn và các đồng nghiệp. Các kết quả này là những kết quả mới không trùng lặp với các công bố trước đó Hà Nội, ngày tháng năm 2015 Tác giả Acknowledgements This thesis was made under a joint supervision “cotutelle” agreement between Observatoire de Paris and Institute of Physics in Hanoi. I spent four months each of three successive years in Paris working with Pr.
Thibaut Le Bertre and the rest of the time in Hanoi with Pr. I would like to thank all people and organizations in Vietnam and in France who helped me with my thesis work and made it possible for me to complete it under as good conditions as possible. From the bottom of my heart, I would like to thank my supervisors, Pr. Thibaut Le Bertre and Pr.
Pierre Darriulat for their guidance, their continuous support and their encouragements. I would like to thank Pr. Thibaut Le Bertre who taught me basic radio astronomy and introduced me to the physics of evolved stars. I highly appreciate his kindness, carefulness and patience.
I am very grateful for his having introduced me to foreign colleagues and for having made it possible for me to attend schools and conferences during my stays in Europe. I would like to thank Pr. Pierre Darriulat who encourages me and protects me in all cases and is always ready to solve any problem I may meet in my research work. I am very lucky to be a student of such wonderful professors.
Dao Tien Khoa and Pr. Daniel Rouan for having accepted to chair the jury and Pr. Stéphane Guilloteau and Dinh Van Trung for their referee work. I particularly thank Dr.
Pham Tuyet Nhung, who spent most of her time working with me during these years and contributed a large part of the results obtained in my thesis. I am grateful for her sharing her life with me, in particular during our stays in France. Her rigor, experience and good judgment helped me a lot in improving the quality of the thesis work. Jan Martin Winters for helping me with the reduction of the IRAM data, spending time discussing about my studies and commenting and correcting the manuscript.
I thank Arancha Castro-Carrizo and her colleagues for having kindly given me X Her and RX Boo data. The Red Rectangle data were observed, calibrated and cleaned by the ALMA staff whom I am deeply grateful for. Pham Tuan Anh for his efforts in answering my questions on the technique and method of interferometry. I am grateful to Dr.
Pham Ngoc Diep and the members of the VATLY team who have been working with me for many years, for having shared with me their stories, their complaints and for the happy and enjoyable environment they create in the lab. I would like to thank our friends Nguyen Quang Rieu, Michèle Gerbaldi, Eric Gérard, Lynn Matthews, Pierre Lesaffre and Alain Maestrini for their moral support and help. I am indebted to the Institute for Nuclear Science and Technology and the Vietnam Satellite Cen- tre for their support. Financial support from the French Embassy in Hanoi, Campus France in Paris, the Rencontres du Vietnam and the Odon Vallet foundation, the World Laboratory and NAFOSTED is gratefully acknowledged.
Finally, I wish to thank my husband and my family who are always besides me, encouraging and supporting me in my research work. ABBREVIATION Asymptotic Giant Branch AGB Atacama Large Milimeter/Sub-milimeter Array ALMA CircumStellar Envelope CSE Five-hundred-meter Aperture Spherical Telescope FAST Hertzsprung-Russell diagram HR diagram Infrared Astronomical Satellite IRAS Institut de Radioastronomie Millimétrique IRAM InterStellar Medium ISM Jansky Very Large Array JVLA Local Standard of Rest LSR Low-Noise Amplifier LNA Main Sequence MS NOrth Extended Millimeter Array NOEMA On-the-fly OTF Planetary Nebula PN Plateau de Bure interferometer PdBI Point Spread Function PSF Pulse-Driven Convective Zone PDCZ Red Giant Branch RGB Spectrum Energy Distribution SED Thermal Pulse TP Very Large Array VLA White Dwarfs WD Contents 1 INTRODUCTION 1 1.1 An introduction to AGB stars .6 Mass-loss rate .2 Asymmetries in AGB and Post AGB stars .1 Generalities on asymmetries .4 Interaction with the ISM .4 The Nançay and Pico Veleta radio telescopes .5 The Plateau de Bure and VLA interferometers .6 The 21 cm line .7 Molecular lines: CO rotation lines .8 Transfer of radiation. 35 3 RS Cnc: CO OBSERVATIONS AND MODEL 41 3.2 Review of the 2004-2005 and earlier CO observations .3 The new 2011 observations .4 Modelling the wind .2 Adequacy of the model .3 Emission, absorption and dissociation .4 Fitting the CO(1-0) and CO(2-1) data .1 Signatures of central symmetry .2 Central asymmetry in the CO(1-0) data .3 CO(1-0): mapping the asymmetric excess .6 Reprocessed data and global analysis 1 .1 Description of CO(1-0) and CO(2-1) emissions using a centrally symmetric model 66 3.2 Deviation from central symmetry in CO(1-0) and CO(2-1) emission. 72 4 CO EMISSION FROM EP Aqr 2 77 4.2 Observing a star along its symmetry axis .3 Comparison of the observations with a bipolar outflow model .4 The CO(1-0) to CO(2-1) flux ratio .5 Evaluation of the effective density in the star meridian plane .6 The mean Doppler velocity of the narrow line component.
91 1 The content of this section has been published (Nhung et al. 2015a) 2 The content of this chapter has been published (Nhung et al. 96 5 CO EMISSION FROM THE RED RECTANGLE 3 97 5.4 Gas effective density .5 Temperature and density distributions .8 Continuum and dust .10 Summary and conclusions. 114 6 CO EMISSION OF OTHER STARS 117 6.1 X Her and RX Boo.
124 7 H i OBSERVATIONS OF THE WIND-ISM INTERACTION 127 7.1 Freely expanding wind (scenario 1) .2 Single detached shell (scenario 2) .3 Villaver et al.1 Optically thin approximation .2 Spectral variations of the background .3 Comparison with observations. 138 3 The content of this chapter has been published in Research in Astronomy and Astrophysics (Tuan Anh et al. 142 8 CONCLUSION AND PERSPECTIVES 145 8. 150 Appendix A 153 Appendix B 167 IV List of Figures 1.1 Sketch of the structure and environment of an AGB star (with the original idea from Le Bertre 1997).2 Mass and radius scales for an AGB star of one solar mass (Habing & Olofsson 2004).3 Evolution in the H-R diagram of a star having the metallicity of the Sun and twice its mass (Herwig 2005).The number labels for each evolutionary phase indicates the log of the approximate duration (in years).4 Details of the RGB and AGB evolution for a 1 solar mass star (Habing & Olofsson 2004).
Note the broken abscissa scale.6 Third dredge-up in a 2 solar mass AGB star following a TP. The red and blue lines mark the boundaries of the H and He free core respectively. Convection zones are shown in green (Herwig 2005).7 Formation of a dust shell around a carbon rich AGB star (Woitke & Niccolini 2005). The white disks mark the star photosphere and black regions are not included in the model.
The star has C/O=2, Te f f =3600 K and L/L⊙ =3000. The degree of condensation is displayed in the left panel and the dust temperature in the right panel.8 Synthetic spectra of AGB stars with different C/O ratios (Gustafsson et al.9 Period-luminosity relation for optically visible red variables in a 0.5◦ region of the LMC. The solid line shows the Hughes & Wood (1990) relation for Miras.10 Positions of selected mass shells in AGB atmospheres for two C/O values, 1. Time is measured in piston periods P and radius in units of stellar radius.
Model parameters are (L∗ , M∗ , T ∗ and P): 104 L⊙ , 1.11 Time dependence (starting from the first TP) of various quantities during the TP-AGB phase of a star having a mass of 1. The dotted line marks the end of the AGB phase. M6 is the mass-loss rate in units of 10−6 solar masses per year (Vassiliadis & Wood 1993).12 A HST gallery of Planetary Nebulae.13 Schematic evolution of close binaries (Jorissen 2004).14 The transient torus scenario (Frankowski & Jorissen 2007).15 Radio continuum map of post-AGB star IRAS 15445-5449 at 22.0 GHz (contours) over- laid on the mid-infrared VLTI image.1 The 30 m dish of the IRAM Pico Veleta radio telescope.2 Dependence on frequency of the atmospheric transmission at PdBI (2550 m). The dif- ferent transmission curves are calculated for the amounts of water vapour (in mm) given on the right.3 PSF pattern of a typical parabolic antenna response.4 Plateau de Bure Interferometer: overall view (left) and a single dish (right).5 Left: Principle schematics of the on-line treatment of the signals from a pair of antennas.
Right: Principle schematics of measurement of two visibility components.6 The Nançay (France) radio telescope. The tilting plane mirror in the background sends an image of the source to the fixed spherical mirror in the foreground. The mobile receiver system is visible between the two mirrors.7 An antenna of the VLA (left) and an overview of the whole array (right).8 Hyperfine splitting of the hydrogen ground state .9 The distribution of molecular clouds in the Milky Way as traced at 115 GHz by the CO(1- 0) transition (galactic coordinates with galactic centre in the centre of the figure) (Dame et al.10 Left: Energy levels of a molecule. Right: Rotation of a diatomic molecule.11 Dependence of the fractional population at different rotational levels of CO molecule on kinetic temperature.12 The CO(1-0) (left) and CO(2-1) (right) fluxes of 4′′ spherical winds expanding with ve- locity 8 km s−1 without absorption effect (black) and with the effect at different values of mass loss rates: 10−7 M⊙ yr−1 (red), 10−6 M⊙ yr−1 (×0.1, green) and 10−5 M⊙ yr−1 (×0.
Distance of the source is d=122 pc.13 The comparison between the red-shifted parts (red) and the blue-shifted parts (blue) of the CO(1-0) (left) and CO(2-1) (right) fluxes shown in Figure 2. The black line shows the flux without the absorption effect.14 Observed absorption spectra caused by a background and optical depth of the source having Gaussian distributions (Levinson & Brown 1980).