Module 5 - 5.5.1 Stars Flashcards
Planets (definition)
Bodies that move in circular/elliptical orbits around a star
Planetary Satellites (definition)
Bodies that orbit planets
Comets (definition)
Large, rocky balls of ice that travel in highly elliptical orbits around stars
Solar Systems (definition)
A collection of planets, their moons and smaller bodies (asteroids, meteoroids and comets) that orbit around a star
Galaxies (definition)
Clusters of many billions of stars held together by gravity
The Universe (definition)
All existing matter and space considered as a whole
The Universe is
expanding
The further galaxies are apart from one another
the faster they will move apart
Stars in a galxy rotate around
the galaxy’s centre of mass
Planets are formed when
interstellar dust is attracted into larger clumps
Comets
- orbit around
- come from
- stars from very far away
- a more distant place called the Oort Cloud
Low Mass Stars: mass between
High Mass Stars: mass between
- 0.5MSun and 10MSun
- > 10MSun
Life Cycle Route of a Low Mass Star
- stellar nebula
- protostar
- main sequence star
- red giant star
- planetary nebula
- white dwarf
- black dwarf
Life Cycle Route of a High Mass Star
- stellar nebula
- protostar
- main sequence star
- red super giant
- supernova
- neutron star or black hole
Nebulae (definition)
Giant clouds of hydrogen gas and interstellar dust that stars are formed from
The higher the mass of a main sequence star (3)
- the shorter a life they have
- the less time they spend on this stage
- have more fuel but use it up faster
Pulsars (4)
- neutron stars with a large magnetic field
- rotate rapidly
- emit highly directional bursts of em radiation
- frequency of the radiation is assumed to be the rate at which the star and its magnetic field rotates
A Singularity (definition)
A theoretical point at which matter is compressed to an infinitely small and dense point and the law of physics as we know them break down
Electron Degeneracy Pressure (definition)
The pressure that stops the gravitational collapse of a low mass star
Electron Degeneracy Pressure (process) (4)
- when matter is compressed into a very small volume, electrons are no longer free to move between energy levels
- as core contracts, compression forces electrons into higher energy levels since they have nowhere else to go
- this rush of electrons finding an available space creates a pressure called the Electron Degeneracy Pressure
- results in an outward acting force
Electron Degeneracy Pressure Appears at which stage in the life cycle of a star (2)
- prevents further collapse so results in a stable while dwarf star
- Electron Degeneracy Pressure balances inwards gravitational force
The luminosity of a star is (definition)
the total energy the star emits per second
The Hertzsprung Russel diagram shows (2) (y and x axis)
- the positions of stars on a scatter graph
- based on their luminosities and temperatures
- y axis: increasing luminosity
- x axis: decreasing temperature
The Hertzsprung Russel diagram shows that for main sequence stars
their luminosity increases with surface temperature
