Nghiên cứu lớp vỏ của các sao khổng lồ đỏ ở bước sóng vô tuyến

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. GS. Pierre Darriulat, Trung tâm Vũ trụ Việt Nam

2. GS. Thibaut Le Bertre, Đài thiên văn Paris

Hà Nội – 2017

MINISTRY OF SCIENCE AND

TECHNOLOGY

VIETNAM ACADEMY OF

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

TECHNOLOGY

VIETNAM ACADEMY OF

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. Prof.. Pierre Darriulat, Vietnam National Space Center

2. Prof. 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. Pierre Darriulat. 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.

I thank Pr. 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. I thank Dr. 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. I thank Dr. 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 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1

1.1.1 An overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1

1.1.2 Nucleosynthesis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4

1.1.3 Dust . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5

1.1.4 Gas molecules . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8

1.1.5 Variability . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9

1.1.6 Mass-loss rate . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10

1.2 Asymmetries in AGB and Post AGB stars . . . . . . . . . . . . . . . . . . . . . . . . . 14

1.2.1 Generalities on asymmetries . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14

1.2.2 Binaries . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15

1.2.3 Magnetic fields . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16

1.2.4 Interaction with the ISM . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17

1.3 Outline . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18

2 RADIO ASTRONOMY 21

2.1 Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21

2.2 Radio instruments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23

2.2.1 Antennas . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23

2.2.2 Receivers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25

2.3 Interferometry . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26

2.4 The Nançay and Pico Veleta radio telescopes . . . . . . . . . . . . . . . . . . . . . . . 30

2.5 The Plateau de Bure and VLA interferometers . . . . . . . . . . . . . . . . . . . . . . . 31

2.6 The 21 cm line . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32

I