Our Sun and Other Stars
When did our Sun form?
5 billion years ago
How long does it take from the Sun to reach us?
8 minutes
HR diagram
A graph relating the temperature and luminosity of stars
What is a star?
A huge ball of hot gas held together by gravity
Nebula
A large cloud of dust and gas in space where stars are born
main sequence star
A normal star that is undergoing nuclear fusion. Our sun is an example of this.
White Dwarf Star
A small, hot, dim star that is the leftover center of a red giant
What is the closest star to our Sun? How far away is it?
Alpha Centauri, 4.22 light years
What are the two main forces that act on gases in a star?
An inward pull due to gravity and an outward push due to the explosive pressure of burning fuel
Black Hole
An object in space whose gravity is so strong not even light can escape.
Which characteristic of stars changes with distance?
Apparent brightness
What is the hottest star(color)?
Blue
What are 4 characteristics that astronomers use to classify stars
Color, Temperature, Size, Brightness
What does fuse mean?
Combine to form one
What does the Sun give out?
Heat, Light, and Radiation
What fuels the Sun's enormous energy output?
Hydrogen
Apparent Brightness (magnitude) depends on which two properties?
Luminosity and distance when viewed from Earth.
Life cycle of a small/medium mass star
Nebula, Main Sequence, Red Giant, White Dwarf Star
What powers the Sun?
Nuclear fusion in the core
Which two events occur when gravity causes a nebula to collapse into itself?
Nuclear fusion starts and a new star forms.
Red Giant Star
Once the star runs out of fuel it expands and cools
What is the coolest star(color)?
Red
Where is the Sun located?
The Sun is at the center of our solar system.
Luminosity
The brightness of a celestial object
Where does nuclear fusion occur in the Sun?
core
What two factors determine how bright a star looks from earth
size and temperature
What is a lightyear?
the distance light travels in a year