Stellar Formation and Circum-Stellar Medium

Code:

AST4011

Acronym:

AST4011

Level:

400

Keywords
Classification	Keyword
OFICIAL	Astronomy

Instance: 2023/2024 - 2S

Active?	Yes
Responsible unit:	Department of Physics and Astronomy
Course/CS Responsible:	Master in Astronomy and Astrophysics

Cycles of Study/Courses

Acronym	No. of Students	Study Plan	Curricular Years	Credits UCN	Credits ECTS	Contact hours	Total Time
M:A_ASTR	13	Study plan since academic year 2023/2024	1	-	6	42	162
			2

Teaching language

English
Obs.: As aulas serão em português caso todos dominem esta língua.

Objectives

The processes associated with the formation and the early evolution of stars are presented. The period in analysis includes the molecular clouds formation, the formation of the proto-star and the pre-main-sequence evolution before the star reaches the main sequence. Complementing the theoretical part, we present observational examples of the different stages of evolution of a young star.

Learning outcomes and competences

At the end the student will have a global view of the theories of star formation and pre-main sequence stellar evolution. The student will also have a global view over the observational component that is used for the study of molecular clouds, protostars and circumstellar medium.

Working method

Presencial

Program

I - Star Formation in our Galaxy

1. Overview

1. Stellar Nurseries
2. Stars and their evolution
3. The Galactic context

2. Interstellar Medium (ISM)

1. Galactic Gas
2. Phases of the ISM
3. Insterstellar Dust - Extinsion/Emission - Properties of the grains

3. Molecular Clouds

1. Giant Molecular Clouds
2. Virial Theorem Analysis
3. Dense Cores

II - Physical Processes in Molecular Clouds

1. Introduction to Radiative Transfer

2. Molecular Transitions

1. Interstellar Molecules
2. Hydrogen (H2)
3. Carbon-Monoxide (CO)
4. Applications of CO

3. Heating and Cooling

1. Cosmic Rays
2. Interstellar Radiation
3. Cooling by Atoms, Molecules and Dust

4. Cloud Thermal Structure

1. The Buildup of Molecules
2. The Molecular Interior

III - From Clouds to Stars

1. Cloud Equilibrium and Stability

1. Isothermal Spheres and the Jeans Mass
2. Magnetostatic Configurations

2. The Collapse of Dense Cores

1. Ambipolar Diffusion
2. Inside-Out Collapse

3. Protostars

1. First Core and Main Accretion Phase

IV - Pre-Main Sequence Stars

1 - T-Tauri Stars

1. Line and Continuum Emission
2. Outflow and Infall
3. Circunstellar Disks

2 - Herbig Ae/Be Stars

1. Basic Properties
2. Gaseous and Debris Disks

V - Accretion discs
1. Theory of standard accretion discs

1. Equations of conservation and the difusion equation
2. Stationary discs
3. Boundary conditions

2. Observations vs Theory

1. Spectral Energy distribution
2. Spectral emission from an optically thick steady disc
3. Sources of excess emission

3. Introduction to magnetospheric models

Mandatory literature

Stahler Steven W.; The formation of stars. ISBN: 3-527-40559-3
Frank J.; Accretion power in astrophysics

Complementary Bibliography

Lee Hartmann; Accretion Processes in Star Formation, Cambridge University Press, 2009. ISBN: 978-0-521-53199-3
Donald E. Osterbrock; Astrophysics of gaseous nebulae and active galactic nuclei. ISBN: 0-935702-22-9
Gray David F.; The observation and analysis of stellar photospheres. ISBN: 0-521-85186-6
Philip J. Armitage; Astrophysics of Planet Formation, Cambridge University Press, 2010. ISBN: 978-0-521-88745-8

Teaching methods and learning activities

Multimedia presentations and Tutorial guidance.

The support material of the course will be available via the Moodle UP, including a copy of the slides used. There is a main reference book that is the main bibliography, but for some components of the course complementary bibliography and/or scientific articles may be used.

Software

Python
Latex

keywords

Physical sciences
Physical sciences > Astronomy
Physical sciences > Astronomy > Astrophysics

Evaluation Type

Distributed evaluation with final exam

Assessment Components

designation	Weight (%)
Exame	60,00
Trabalho prático ou de projeto	15,00
Trabalho escrito	15,00
Apresentação/discussão de um trabalho científico	10,00
Total:	100,00

Amount of time allocated to each course unit

designation	Time (hours)
Estudo autónomo	65,00
Frequência das aulas	42,00
Trabalho escrito	20,00
Trabalho laboratorial	30,00
Apresentação/discussão de um trabalho científico	5,00
Total:	162,00

Eligibility for exams

There will be no attendance record in classes of this curricular unit.



In the final exam, students are required to obtain a classification higher than 7 in 20.

Calculation formula of final grade

The final grade is obtained through two components:
Option A
1) 70% - a final written exam
2) 30% - computational work developped during the semester with a final written report

Option B
1) 60% - a final written exam
2) 10% Oral presentation of a paper
3) 30% - computational work developped during the semester with a final written report

The practical computational work task  will be carried out throughout the first half of the  semester under the lecturer  supervision. The deadline for submitting the written report and code is April 7.

Special assessment (TE, DA, ...)

The students with a special status, namely working-students will be subjected to an evaluation equal to the remaining students.

Working-students will be consulted regarding the dates of the oral presentation  so that they can organize their schedule and be present at this assessment moment, if they so wish.

Classification improvement

The student may improve the classification in the written exam (weight of 60% or 70 % in the final assessment).

It will not be possible to improve the classification in the pratical work task or in the oral presentation.

Observations

Jury:
Jorge Filipe Gameiro
João Lima