Astronomy 1Y:
Stellar Astrophysics I
Room 312, Kelvin Building. Dr M.A. Hendry
(+ Prof J.C. Brown)
Beginning 28.01.02
Stellar Astrophysics I and II deal with
the observations, classification, and modelling of stars and their evolution.
The course divides into two parts. Stellar Astrophysics I deals with the
basic observations of stars in our galaxy, the different stellar types
and their classification (8 lectures: Dr M.A. Hendry). We then discuss
the source of luminosity of stars, the structure of main sequence stars
and their evolution off the main sequence (4 lectures: Prof J.C. Brown).
Stellar Astrophysics II (called 'Compact Objects' - 8 lectures, Prof Brown)
deals with the later stages of stellar evolution and the properties of
the so-called compact stars, white dwarfs and neutron stars, and black
holes, and our theoretical understanding of these objects.
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Course details
Copies of lecture notes will appear here as the
course proceeds. They are for reference only, and should be
used to replace your own lecture notes. You will find the course much harder
if you don't create your own written version, so please do not print
these notes out in quantity.
References to the relevant sections of 'An Introduction
to Modern Astrophysics', by Carroll & Ostlie, will be given at the
beginning of each section. Note that there is much useful and relevant
material to be found in this textbook, but there is also a lot of advanced
material which lies well beyond the scope of this course. (Carroll &
Ostlie is the recommended textbook for Astronomy A2). You should therefore
access the textbook with some caution: don't be immediately discouraged
if you find parts of it difficult to follow, and certainly don't assume
that all material from Carroll & Ostlie is examinable! If in
doubt, ask the course lecturer for advice!
Measuring the stars
(Carroll & Ostlie chapter 3. Note that some Americans
still like to use the old-fashioned erg as a unit of energy. 1 erg = 10-7
joule. e.g., page 67 example 3.2, F = 1.360 x 106
erg s-1 cm-2 = 1.360 x 103 J s-1
m-2)
The Sun; range of luminosities, masses and radii; effective temperatures
Pictures: [ Pressure vs Gravity | Milky
Way star field | Solar Disk | Betelgeuse
| Orion ]
Handouts:[ Blackbody
radiation and Planck's radiation law | Determining
effective temperature ]
Star types
(Carroll & Ostlie, section 8.2)
Hertzsprung-Russell (H-R) luminosity v temperature diagram; main sequence;
red giants; white dwarfs;
Pictures: [ Pistol star |
Brown
dwarfs | Sun as a red giant
| Planetary Nebula | HST
white dwarfs | Pleiades
| Praesepe | 47
Tuc | M15 ]
Handouts: [ The
Hertzprung-Russell diagram | A
real Hertzprung -Russell diagram | Parallax
| Apparent and absolute magnitude
]
Variable and binary stars; light curves and radial velocity curves
(Carroll & Ostlie chapter 7)
Pictures: [ SN1987A (supernova)
| Nova Cygni (cataclysmic variable)
| CV painting | Cepheids
in M100 | spectroscopic binary
Mizar ]
Handouts: [ Periodic variables
1 | Periodic variables
2 ]
Stellar atmospheres -photosphere, chromosphere, and corona;
emission and absorption; ionisation; line formation
(Carroll & Ostlie chapter 11 and chapter 8)
Pictures:[ solar photosphere
| solar chromosphere |
solar
corona in FeXII | solar corona during
eclipse | Bohr atom | absorption
| emission | solar
spectrum ]
Handouts: [ Solar atmosphere,
Kirchoff's laws & hydrogen series |
Line
strengths vs T ]
Classification of stars - spectral classification
(OBAFGKM); chemical composition, mass luminosity relationship for main
sequence stars
(Carroll & Ostlie chapter 8)
Handouts: [ Spectral
classification 1 | Spectral
classification 2 ]
Star formation - gravitational collapse, protostars and evolutionary
tracks; free-fall and Kelvin-Helmholtz timescales; T-Tauri stars
and bipolar outflows; emission nebulae
(Carroll & Ostlie chapter 12)
Pictures: [M16 The Eagle Nebula |
protoplanetary
disks in Orion | Jets
from young stars | 30 Doradus
| Orion Nebula |
Rosette Nebula ]
Handouts:[ Pre-Main Sequence stellar
evolution ]
Books
There is no single textbook which is an essential purchase
for this module. However An
Introduction to Modern Astrophysics, B W Carroll and D A Ostlie, Addison
Wesley is strongly recommended, and is essential for the Astronomy
2 course It has its own website
here. Its approach is in places more advanced than required for A1X
and Y, however there is much useful material in it.
For wider background reading, students may find the following
list useful:
-
Fundamental Astronomy - 2nd Enlarged Edition, H Karttunen et al, Springer
-Verlag
-
The
Dynamic Universe, 4th Ed, T P Snow, West Publishing Co
-
Astronomy
- Principles and Practice, 3rd Ed, A E Roy & D Clarke, Hilger
-
Astronomy
- Structure of the Universe, 3rd Ed, A E Roy & D Clarke, Hilger
-
Collins Dictionary of Astronomy,
Ed. V Illingworth, Harper Collins
-
or Oxford Dictionary Of Astronomy,
Ed. Ian Ridpath, Oxford University Press
