Unit 5 - Astrophysics - Classification of Stars Flashcards
Define ‘Apparant Magnitude’.
The brightness of a star as seen from Earth.
Define ‘Absolute Magnitude’.
The brightness of star if it were at a distance of 10 parsecs from the observer
How do you determine the ratio of brightnesses between adjacent star classes.
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What is the relationship between apparent and absolute magnitude?
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Describe for Class O star:
Temperature.
Colour.
Prominent absorbtion lines.
25,000-50,000K
Blue
ionised and neutral Helium and weak hydrogen
Describe for Class B star:
Temperature.
Colour.
Prominent absorbtion lines.
11,000-25,000K
Blue/White
Neutral helium and moderate hydrogen.
Describe for Class A star:
Temperature.
Colour.
Prominent absorbtion lines.
7,500 - 11,000K
White with blue tinge
Strong hydrogen and ionised metals
Describe for Class F star:
Temperature.
Colour.
Prominent absorbtion lines.
6,000-7,500K
White
Ionised metal and weak hydrogen
Describe for Class G star:
Temperature.
Colour.
Prominent absorbtion lines.
5,000K-6,000K
Yellow/White
Neutral and ionsied metal, weak hydrogen
Describe for Class K star:
Temperature.
Colour.
Prominent absorbtion lines.
3,500-5,000K
Orange
Neutral metals
Describe for Class M star:
Temperature.
Colour.
Prominent absorbtion lines.
2,000-3,500
Red
molecules/neutral metals/Titanium oxide
What class of star is the sun in?
Class G
Define a black body.
A black body is a body that completely absorbs all wavelengths of electromagnetic radiation that fall upon it and reflects and transmits none.
Draw a black body curve for three different temperatures: P,Q,R where P>Q>R
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What is Wien’s Displacement Law
That the product of the maximum wavelength and the temperature is constant.
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