2019-2020 / SPAT0007-2

Variable stars

Duration

20h Th, 10h Pr

Number of credits

 Master in space sciences (120 ECTS)3 crédits 

Lecturer

Grégor Rauw

Language(s) of instruction

English language

Organisation and examination

Teaching in the first semester, review in January

Schedule

Schedule online

Units courses prerequisite and corequisite

Prerequisite or corequisite units are presented within each program

Learning unit contents

In astrophysics you are only allowed to watch your targets, you cannot manipulate them in a lab. Therefore, it is important to gather as much information as possible to understand the nature of the objects that are being investigated. In this context, temporal variability provides a precious tool.
In this course, the observational properties of many different categories of variable stars (including single and multiple objects) are presented. Various techniques to study these objects are described and the latest models derived from these observations are presented.
An important part of the course deals with multiple systems harbouring two or more stars. We consider the techniques used to infer fundamental stellar parameters (masses, radii,...) from the study of spectroscopic and eclipsing binaries. We also discuss interacting binaries, such as cataclysmic variables, novae, X-ray binaries,... For single stars, the lectures focus on the different categories of pulsating stars across the Hertzsprung-Russell diagram as well as their period-luminosity relations. The variability of massive stars, mainly due to structures in their stellar winds, is also described. Finally, we address some categories of late-type stars that display variability: R Corona Borealis stars, pre-main sequence stars and active, flaring objects.

Learning outcomes of the learning unit

After completing this course, the students will be able to answer notably three major questions:






  • What are the general properties of variable stars and how can they be used to better understand the processes in the Universe?
  • How to extract the most relevant information from spectroscopic time-series and/or from photometric light curves?
  • How to interpret the observed variability?

Prerequisite knowledge and skills

Good knowledge of mathematics, physics and classical mechanics.

Planned learning activities and teaching methods

During one or two hand-on session(s), the students have the opportunity to analyze the light curve of an eclipsing binary system and/or the radial velocity curve of a spectroscopic binary using dedicated software.
Based on the techniques taught during the hand-on sessions , the students will complete a personal project consisting either of the preparation of new observations of a variable star with the TIGRE robotic telescope, or of the analysis of such observations.

Mode of delivery (face-to-face ; distance-learning)

The face-to-face lectures are usually scheduled as 3h/week during the first semester. The course is only offered during uneven years.

Recommended or required readings

The lecture notes are provided in English as a pdf file.

Assessment methods and criteria

The evaluation emphasizes the understanding of the course and the ability to use the techniques that have been taught. To successfully pass the exam students have to learn and understand the course.
The assessment is composed of two parts: 33% based upon a short report on the personal project  and another 67% based upon an oral examination.

Work placement(s)

Organizational remarks

The course is offered once every two years: uneven academic years (e.g. 2015 - 2016).

Contacts

Prof. Gregor Rauw Institut d'Astrophysique et Géophysique, Bât. B5c Allée du 6 Août, 19c 4000 Liège
Tel. +32-(0)4 366 9740 e-mail: g.rauw@uliege.be

Adaptation of teaching commitments following the COVID-19 pandemic for the May-June 2020 session

Teaching methods implemented : distance-learning

Assessment subjects

Assessment methods

Contacts

Adaptation of teaching commitments following the COVID-19 pandemic for the Aug-Sept 2020 session

Assessment subjects

The assessment concerns all the topics addressed in the course. However, due to the restrictions related to the Covid-19 pandemic, the assessment method is modified compared to the January session.

Assessment methods

The students choose an article from a list that they are provided with on the eCampus site (and solely from that list). They read the article and write a report of maximum 10 A4 pages (character size 11pt) putting the article into the context of the course. The report must be submitted at the beginning of the exam session (see hereafter). Students who fail to get a mark of 12/20 or better for their report will be informed and will be invited to defend their report through a Lifesize session that will take place during the second half of the session and that will count for 1/3 of the final mark. The remaining 2/3 corresponding to the mark of the personal work. Those students who get a mark higher than 12/20 for their personal work will have this mark as their final mark.
The timeline is the following:
- Thursday 20 August 2020 at noon: deadline for submission of the written report (see instructions on eCampus)
- Tuesday 25 August 2020: information to the students invited to present their report on Lifesize
- Date to be decided (same date for all students) between 27 August and 8 September: oral presentation.

Contacts

E-mail: g.rauw@uliege.be