Substantial summary: Planetary formation seen with ALMA - Gas and dust properties in protoplanetary disks around young low mass stars

This thesis investigates the properties of the protoplanetary disk surrounding a triple low-mass stellar system, GG Tau A, using interferometric observations of trace molecules such as 12CO, 13CO, C18O, DCO+, HCO+ and H2S, and of multi-wavelength dust emission.
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Substantial summary: Planetary formation seen with ALMA - Gas and dust properties in protoplanetary disks around young low mass starsMINISTRY OF EDUCATION VIETNAM ACADEMY OF AND TRAINING SCIENCE AND TECHNOLOGYGRADUATE UNIVERSITY OF SCIENCE AND TECHNOLOGY ……..….***………… NGUYEN THI PHUONG PLANETARY FORMATION SEEN WITH ALMA: GAS ANDDUST PROPERTIES IN PROTOPLANETARY DISKS AROUND HỌC VIỆN KHOA YOUNG HỌC VÀ STARS LOW-MASS CÔNG NGHỆ ……..….***………… Major: Atomic physics Code: 9 44 01 06 SUBSTANTIAL SUMMARY Hanoi – 2019This thesis has been completed at Laboratory of Astrophysics ofBordeaux, University of Bordeaux and Graduate University of Scienceand Technology – Vietnam Academy of Science and TechnologySupervisors: 1. Dr. Pham Ngoc Diep – Vietnam National Space Center, Vietnam Academy of Science and Technology 2. Dr. Anne Dutrey, Laboratory of Astrophysics of Bordeaux, University of BordeauxReferees : HỌCDartois1. TS. Emmanuel VIỆN KHOA HỌC – Institut VÀ CÔNG des Sciences NGHỆ Moléculaires d’Orsay,France ……..….***………… 2. GS.TS. Hideko Nomura – National Astronomical Observatory of JapanThis thesis will be defended at Graduate University of Science andTechnology – Vietnam Academy of Science and Technology at 9h00,November 22, 2019This thesis can be found at:- Library of Graduate University of Science and Technology- National Library of VietnamList of publications1. Phuong, N. T., Dutrey, A., Diep, P. N, Guilloteau, S., Chapillon, E., Di Folco, E., Tang, Y-W., Pietu, V., Bary, J., Beck, T. , Hersant , F., Hoai, D.T., Hure , J.M. , Nhung, P.T. , Pierens, A. , Tuan-Anh, P., GG Tau A: properties and dynamics from the cavity to the outer disk, submitted to A&A.2. Phuong, N. T., Chapillon, E., Majumdar, L., Dutrey, A., Guilloteau, S., Piétu, V., Wakelam, V., Diep, P. N., Tang, Y.- W., Beck, T., & Bary, J., First detection of H2S in a protoplanetary disk. The dense GG Tauri A ring, A&A, 616, L5, 2018.3. Phuong, N. T., Diep, P. N., Dutrey, A., Chapillon, E., Darriulat, P., Guilloteau, S., Hoai, D. T., Tuyet Nhung, P., Tang, Y.-W., Thao, N. T., & Tuan-Anh, P., Morphology of the 13CO(3-2) millimetre emission across the gas disc surrounding the triple protostar GG Tau A using ALMA observations, RAA, 18, 031, 2018. Understanding how planetary systems form is a majorchallenge of Astrophysics in the 21st century. For this pur-pose, observing young low-mass stars, similar to the Sun whenit was in its infancy is a necessary step. Indeed, planets formfrom the rotating disk of gas and dust orbiting around theseyoung stars (also called T Tauri stars). This disk is itselfa residual from the molecular cloud which has formed thecentral star, and so called protoplanetary disk. As a con-sequence, determining the physics and chemistry at play inthese protoplanetary disks has become an important domainof the modern astrophysics requesting both detailed obser-vations and sophisticated models. Thus constraining initialconditions leading to planetary systems by making relevantcomparisons with planet formation models requests an obser-vational evaluation of the physical properties (density, temper-ature, turbulence, etc) and chemical evolution of the gas anddust disks surrounding T Tauri stars. An important sourceof complexity for the observations resides in the fact thatthe determination of these fundamental physical parametersis strongly degenerated within a single observation. The roleof the observer is therefore to define an observing strategy,e.g. by observing several molecules, which allows an accuratederivation of the physical properties by minimizing the impactof possible degeneracies. Knowing the properties of the dust(nature, size, morphology) is essential to understand the for- 1mation of planetary embryos but also the genesis of complexmolecules. Many organic molecules form onto grain surfaceswhere gaseous molecules freeze out as soon as the temperatureis cold enough (e.g. 17 K for CO) and interact with moleculesalready trapped onto grains. This thesis investigates the prop-erties of the protoplanetary disk surrounding a triple low-massstellar system, GG Tau A, using interferometric observationsof trace molecules such as 12 CO, 13 CO, C18 O, DCO+ , HCO+and H2 S, and of multi-wavelength dust emission.Chapter 1 introduces the topic and the current knowledgeof protoplanetary disks. The special case of protoplanetarydisks surrounding binary systems is introduced both for thetheoretical studies and for the observations. The second partof the Chapter presents the known properties on the GG TauA system.Chapter 2 summarizes some basic points about instruments,observations and analysis methods used in the present study.It briefly introduces IRAM and ALMA interferometers, theobservations carried out with these facilities and data reduc-tion. It also present the principles of radio interferometry anddeconvolution. It also recalls the bases of radiative transfer,and a radiative transfer code (DiskFit) is introduced at theend of the Chapter. 2Figure 1: Brightness of the dust ring continuum emission. Topleft: sky map, the black ellipse is the fit to hRi shown in thebottom left panel; the yellow arrow points to the region ofthe ”hot spot” observed by Dutrey et al. (2014) and Tanget al. (2016) in 12 CO(6–5) and 12 CO(3–2) emissions. Topright: The dependence on R of the brightness averaged overpos ...