Download The Stars

The Stars
Stars vary greatly in size, brightness, temperature, and colour. Here are some of the things we have
learned about the properties of stars.
Measuring distance
Just as with the kilometre, the AU is not very useful when we start to study stuff outside of our Solar
System. A much larger unit called the Light-year (Ly). One light-year (1Ly) is the distance that light
travels through space in one year. (C = 300 000 km/s)
That is fast enough to circle the Earth _______ times every second.
Star Brightness
______________ is the amount of energy produced by a star each second.
______________ is a measurement of how bright a star appears from earth.
______________ is the measure of how bright a celestial object would appear at 33 ly.
How bright a star seems from the Earth is a factor of ______________ and _____________ the star is.
Star Colour and Temperature
The colour of a star depends on their ________________.
Scale:
Red = 3000 0C
Orange/yellow = 5000 0C
White = +10 000 0C
Plotting the Properties of Stars
Two astronomers created a special kind of graph that compares star brightness with their
________________ ________________. When this was plotted it showed that these properties are
related.
For example, as the temperature of a star __________________, its colour becomes more
__________. It also gets brighter
Grouping Stars
The Hertzsprung-Russell diagram arranges stars into groups based on their brightness, colour and
surface temperature.
1. Arrange these stars in order from
hottest to least hot:
Betelgeuse, – red
Aldeberan – orange
Zeta Orionis – Blue
Polaris – yellow/white
Sun, alpha century – yellow
Rigel, – blue/white
Sirius B – white
2. Beside each star (or pair) classify the
star as a blue supergiant, red supergiant,
or a white dwarf