Stars

Code:

AST2001

Acronym:

AST2001

Level:

200

Keywords
Classification	Keyword
OFICIAL	Astronomy

Instance: 2019/2020 - 2S

Active?	Yes
Responsible unit:	Department of Physics and Astronomy
Course/CS Responsible:	Bachelor in Chemistry

Cycles of Study/Courses

Acronym	No. of Students	Study Plan	Curricular Years	Credits UCN	Credits ECTS	Contact hours	Total Time
L:B	0	Official Study Plan	3	-	6	56	162
L:CC	0	Plano de estudos a partir de 2014	2	-	6	56	162
			3
L:G	0	study plan from 2017/18	2	-	6	56	162
			3
L:M	1	Official Study Plan	2	-	6	56	162
			3
L:Q	0	study plan from 2016/17	3	-	6	56	162

Teaching language

Portuguese

Objectives

The course aims at providing the fundamental competencies for stellar astrophysics, both in terms of concepts such as physical tools/mathematical descriptui relevant for astronomy. With this training we seek to ensure that the student acquires the ability to understand what a star is and how to use observational data to study the fundamental physics that drive the behavior of the stars. The approach is at an intermediate level, covering the clarification and analysis of concepts, but also giving some emphasis on the formal terms in how these are described. The aim is to develop an understanding of relevant global concepts in stellar astronomy and to build the ability to relate them, including in particular, the description of concepts and physical phenomena that occur inside stars and atmospheres and those that are relevant to describe star formation.

Learning outcomes and competences

The first part of the program is organized to ensure that the fundamental physical concepts are reviewed and discussed at the beginning of the course in order to support the other chapters that focus on the study of stars. After the discussion and the introductory concepts, a detailed discussion of how radiation reaches us after being emitted by the star is covered. This includes an in-depth study of the emission and transfer of radiation on its path between the interior of the star and the detector. It is expected that the student understands the effects of ionization and excitation, producing the observed stellar spectrum, and how the observed information can be used to characterize the atmosphere of the star. Then the course also addresses the physics of the interior, the underling conditions in the interior and the implications for the study of stars being observed. The program ends with a discussion of how evolution (in time) changes the structure of the star, from its initial formation to the final stages of evolution.

Working method

Presencial

Program

1. Introduction: Studying stars. Determination of distances to stars. Radiation theory (basic concepts).


2. Celestial Mechanics: Two body systems. Kepler laws. Characterization of the orbits. Applications in Astronomy (solar system, exoplanets, binaries, etc).


3. Stellar photometry: Black body radiation. Magnitudes. Absorption of radiation. Observations.


4. Stellar spectroscopy: Thermal excitation and ionization (Boltzmann equation, Saha equation). Sources of opacity. Observations.


5. Stellar atmospheres: Radiative transport in atmospheres. Formation and structure of spectral lines.


6. Stellar interiors: Structural equations. Equation of state. Equation for energy production. Equation of energy transport. Stars in the main sequence.


7. Formation and Star Evolution: Proto-star. Eraly stellar evolution. Evolution after the main sequence. Final stages of stellar evolution.

Mandatory literature

Carroll, W.B., Ostlie, D.A.; An Introduction to Modern Astrophysics, Addison Wesley, 1995. ISBN: 0201547309

Complementary Bibliography

Böhm-Vitense, E.; Introduction to Stellar Astrophysics. Vol 1: Basic Stellar Observations and Data, Cambridge University Press, 1989. ISBN: 0521348692
Böhm-Vitense, E; Introduction to Stellar Astrophysics. Vol 2: Stellar Atmospheres, Cambridge University Press, 1989. ISBN: 0521348706
Böhm-Vitense, E; Introduction to Stellar Astrophysics. Vol 3: Stellar Structure and Evolution, Cambridge University Press, 1992. ISBN: 0521348714

Comments from the literature

A wide range of supporting information (sebenta, web resources, documents, articles, book chapters, etc) are provided in the Moodle for the curricular unit.

Teaching methods and learning activities

The course is organized using the lectures to present the material, predominantly using the blackboard to allow the student to follow the construction of the mathematical description for all physical phenomena, in the various items of the program. A component using video projector is also implemented, but more sporadic, in order to consolidate the contents and strengthen the interpretation by discussing the contents being covered in the light of the available observations. In the tutorial classes the student works on the resolution of exercises and on the discussion of representative examples (mainly on how concepts and data are effectively used in the study of specific stars and phenomena).

The methodology aims mainly at strengthening the capacity of interpretation and active use of the concepts being discussed. This is done by ensuring that the student participates actively in the classes (theoretical and tutorial). In order to support this active participation (avoiding that the student uses the class only as an opportunity to collect information), the student is given in advance the support material through Aulas-na-Web (Moodle). Lecturer notes are made available (detailed record of what is covered in the lectures), to allow the student to prepare the lectures and to use the time to complement the notes and to clarify the points that may raise doubts/questions. Together with the lecturer notes, the student also has access to copies of the slides to be presented in class. All this material is available in Aulas-na-Web, along with additional material (including articles, links to material of other relevant courses available in the Internet, useful webpages for specific items of the program, etc.).

With this approach for the teaching methods, we aim at strengthening the component of interpretation, by reducing the weight of the component on memorizing. Note also that during the assessment actions, the student is allowed to use any material (both for the test and exam), in order to put up more emphasis on understanding and use of concepts, than on reproducing information.

In support of the theoretical and practical classes there is an extensive list of exercises, organized by theme, supporting the tutorials and to help the students to develop individual work. Classes are organized based on the suggestion of exercises to work by the lecturer and in exercises requested by the students. All exams from previous academic years are available in Aulas-na-Web to encourage the student to prepare the theoretical and practical classes and to take advantage of the individual study time to overcome any shortfalls in the understanding and use of the concepts and tools discussed in course.

Software

Perusall

keywords

Physical sciences > Astronomy > Astrophysics
Physical sciences > Astronomy

Evaluation Type

Distributed evaluation with final exam

Assessment Components

designation	Weight (%)
Exame	60,00
Participação presencial	5,00
Trabalho escrito	35,00
Total:	100,00

Amount of time allocated to each course unit

designation	Time (hours)
Estudo autónomo	80,00
Frequência das aulas	56,00
Trabalho escrito	26,00
Total:	162,00

Eligibility for exams

The student has frequency to the course if he/she misses no more than 1/3 of the planned classes (T and TP).

Calculation formula of final grade

Continuous evaluation with the revision of the contents (done through Perusall) and the active participation in the lectures (questions, answers, discussion of specific topics, resolution of problems).

The full evaluation includes the continuous evaluation and the final exam. A minimum of 20% (out of 60%) is the exam is required in order to be approved in this course unit.

Access to support material is allowed during the exam (but it can not be shared between students).

Classification improvement

It is possible to improve the grade, but only for the exam component.

Observations

The jury of the curricular unit includes:
   - Mário joão P. F. G. Monteiro
   - Jorge Filipe S. Gameiro