Test 3 TOPICS                                 Review for the FINAL EXAM:           TG –p. means Textbook Guide page

Sun’s atmosphere, Stars, Milky Way.

Main Topics



Sun’s atmosphere

Photosphere, chromosphere, corona – photosphere’s temperature, relative temperature of the three atmospheric layers;



Photosphere – type of heat transfer, results in its special feature;



Magnetic field – its measurement, principle; visible as arches of flares; controls solar sun spot and magnetic activity (periods of each).


Magnitude & brightness

Their mutual relationship; applications for stars & galaxies.

1, 16-19

Distance to celestial objects

4 methods applicable to various distances & objects (angular or stellar parallax, spectroscopic parallax, period - luminosity relationship of Cepheid stars, Hubble’s law – red shift due to universe expansion).

16, 19

(Semi)annual parallax

Its definition & use; what is parsec;


Hertzsprung-Russell diagram

Which star characteristics does it relate (X, Y axes)?
Main sequence stars: which process controls them?
How is pressure-temperature thermostat related to main-sequence stars? How does it work?


Spectroscopic parallax

What is its principle? What it the distance modulus? What is apparent luminosity/magnitude?


Stars formation

Interstellar medium from which stars form, its composition & changes; may trigger the star formation: supernova, ignition of a nearby star, spiral arms of the galaxy.

17 - 18

Intrinsic luminosity/

What is the meaning of “intrinsic (absolute)” amount of visible light or total radiation (luminosity)? How do we define it? Intrinsic means apparent at 10 parsec.


Death of stars

What causes it? What may be the result? How it may appear on the H-R diagram? 3 types of massive objects (end stages of star evolution: white dwarfs, neutron stars, black holes) – mass conditions under which each takes place; size/diameter of each.


MASS of celestial objects

Methods of measurement applicable to various objects:

1. binary star systems: visual binaries, spectroscopic binaries & eclipsing binaries;

2. mass-luminosity relation of the main sequence stars:
luminosity = mass




3 groups: main sequence stars, giants, supergiants, white dwarfs.



3 types: when & where (in which objects) dominates each


Spectral analysis

Star properties which may be (and may be not) determined from it: chemical composition, radial velocity by Doppler’s principle, magnetic field of the radiation source by Zeeman’s effect.

4-5,14, 16-17

MILKY WAY galaxy

2 main components – disk & spherical component; parts of each; How its center & size could be determined?
Differential rotation – its meaning and probable explanation.

19, 20

Tidal flexing & heating of cosmic bodies

Mutual gravitational influence consumes rotational & orbiting energies by flexing of the pertinent bodies causing their internal friction and heating. This may occur by rotation in a strong gravity field, or changing gravity direction and/or intensity (elliptical orbits). The tidal heating may be visible as various types of volcanism (including cryovolcanism), and may terminate by tidal locking of one or more motions, such as Pluto – Charon system: both objects are mutually locked.

3, 10, 14

Tidal heating in the Solar system

Most bodies are tidally heated: the strongest volcanism is on Io (satellite of Jupiter), no volcanism is yet known on Mercury.

10, 14