Stars and Planets Flashcards
What kind of planets are the planets in our solar system?
The closest 4 to the sun are rocky, and the furthest 4 from the sun are gaseous
What units of distance are used in space?
- astronomical unit: the mean distance from the centre of the Earth to the centre of the sun is 1 AU
- light year: the distance that light travels in a year is 1 light year
What is an asteroid?
A lump of rock which orbits the sun. The asteroid belt is between Mars and Jupiter
What is a comet?
Lumps of ice and dust that are in a highly elliptical orbit around the sun
What is the life cycle of a low mass star?
Gravitational collapse of a nebula forms a protostar. If it’s mass is below 8SM, it becomes a yellow, average mass main sequence star. As the star begins running out of hydrogen, it becomes a red giant. It then becomes a planetary nebula and it’s outer layers expand towards space. Finally, it becomes a white dwarf.
What is the life cycle of a high mass star?
Gravitational collapse of a nebula forms a protostar. If it’s mass is above 8SM, it becomes a blue, massive main sequence star. As the star begins running out of hydrogen, it becomes a red supergiant. It then explodes into a supernova, and elements heavier than lead are formed. Stars greater than 25SM will become blackholes, and stars above 8SM but below 25SM will become neutron stars.
What is a brown dwarf?
A failed star that never had enough mass to get hot enough to achieve nuclear fusion
What is a red dwarf?
Low mass stars that do achieve nuclear fusion. They are main sequence stars
What forces act inside a star?
Gravity acts inwards, and gas and radiation pressure act outwards
What happens when an imbalance of pressure occurs within a star?
If pressure in the middle falls, it will shrink, and if pressure in the middle increases, it’s size will increase
What does a Hertzsprung-Russel diagram depict?
Stars according to their temperature and brightness
