Astrophysics Flashcards
How does a:
Nebula form
Force of gravity causes clouds of hydrogen nuclei to form into nebulae
Why is the:
Colour of a star important
- Colour of a star is directly linked to its surface temperature
- coolest stars glow dull red
- medium like sun orange/yello
- hottest - blue white
What is the:
Spectral class groups
OBAFGKM
input sufrace temperature if needed
colour, with mixes, blue - white - yellow - orange - red, no yellow orange or red
Why do:
Brighter stars release light waves with different colours?
Visible light with more energy is released which is more blue
What is:
Difference between apparent and absolute magntitude
- Apparant magnitude is how bright a star looks when viewed from the earth
- Absolute is when viewed from 32.68 light years, which allows to classify the luminosity equally
What is the:
Diagram used to classify stars
Hertzsprung Russell diagram
What is strange about the:
Hertzprung Russell diagram
scale multiplied by 2.5
negative values, which are larger than normal values
4 axis (temperature, spectral class, absolute magnitude, luminosity)
What is the:
Universe
A collection of billion of galaxies which has billions of stars
Difference between:
Orbit of planets and comets
Planets nearly circular, comets eplliptical and moves faster closer to the star orbited
What is the:
Steady state theory
Universe always existed and is expanding, with new matter continuoslly created. Only red shift supporting, and countered by law of conservation of energy
What is support of:
Big Bang
CMBR, as it is uniform everywhere suggesting universe started from same point
Red shift, all stars are moving away
something may be missing
How can:
Electrons be excited
If they absorb exactly enough energy of the next energy level, and need to absorb light waves of an exact frequency
What is an:
Absorption spectra?
As the wavelengths released when of light has to go through a gas, some of the wavelengths are absorbed by the gases in the sun, leading to black lines. Absorption spectra would all look the same if all stars were the same distance from Earth, but galaxies have different amount of red shift leading to the graph shifting to the _____
LEARN SHAPE OF HERTSPRUNG DIAGRAM
WIENS LAW???
Wavenlength of a black body will depend on the temperature of the object
name of:
Light emitted by a hot object
Continuous spectrum
