Astrophysics Flashcards
What is a universe
A large collection of billions of galaxies
What is a galaxy
A large collection of billions of stars
Where is our solar system
In the ‘Milky Way’ galaxy
How does gravitational field strength vary?
According to mass of object
i.e. larger mass means more gravitational attraction
What do moons orbit
Planets
What do planets orbit
Stars
What do satellites orbit
Planets or Earth
What do comets orbit
Stars
How do moons and planets orbit
Roughly circular orbit
At a roughly constant speed
Describe the orbit of comets
Highly elliptical
The comet travels fastest when its nearest the star (where gravitational attraction is strongest)
State the equation linking orbital speed, orbital radius and time period
Orbital speed = 2π x orbital radius
/ time period
Describe the stellar classification scale
O - blue B - blue A - blue F - blue to white G - white to yellow K - orange to red M - Red
What is star colour related to
The stars surface temperature
What is absolute magnitude
Represents the brightness of a star measured at a standard distance
What is a nebula
Clouds of dust and gas
Form through gravitational attraction
What is a main sequence star
Most stars are main sequence
Core temp. of over 10 mil. K when fusion takes place
This is what creates the stars energy over its lifetime
In fusion hydrogen atoms are fused together to make helium
What is a red giant
At the end of a stars lie it swells to 500 times its original size
What is a white dwarf
Once fusion has ceased in a star, just the core is left
Cools over time to become a black dwarf
Describe the evolution of stars
Nebula Protostar Main sequence Red Giant Then: White dwarf, black dwarf or: Supernova Neutron star Blackhole
