Star formation
What forces cause the formation of stars
Gravity plus pressure
On an H–R diagram, what property is shown on the vertical (y) axis?
Luminosity.
When a Sun-like star runs out of hydrogen in its core, what part of the star expands?
The outer layers
What do massive stars become after they leave the main sequence and their outer layers expand?
Supergiants
What do we call a huge collection of stars, gas, and dust held together by gravity?
A galaxy.
What do we call a giant cluster of space clouds
A nebula
On an H–R diagram, where are the hottest stars located: left or right side?
The left side.
What element does a Sun-like star begin fusing after hydrogen runs out?
Helium
When a massive star runs out of fuel and collapses, what explosive event marks its death?
supernova
What word describes the apparent shift in a star’s position when viewed from different places in Earth’s orbit?
Parallax
What is a protostar, and what has to happen to form them
A protostar is a baby star that forms when a cloud of gas and dust in space collapses under gravity, creating a hot, dense ball that isn't yet hot enough for nuclear fusion. Once the core gets hot enough, hydrogen fusion begins, and it becomes a true star
What is the name of the diagonal band on the H–R diagram where most stars, including the Sun, are found?
The main sequence.
What glowing shell of gas is released when a Sun-like star sheds its outer layers near the end of its life?
A planetary nebula.
What extremely dense object can form if the core left after a supernova
A neutron star.
Explain the difference between absolute and apparent brightness
...
What happens to the temperature and pressure inside a protostar as gravity pulls more material inward?
Hydrogen fusion balances gravity's pull
Why do high-mass stars appear in the upper-left part of the H–R diagram?
Because they are both very hot and very luminous.
hat is the hot, dense leftover core of a Sun-like star after it forms a planetary nebula?
A white dwarf.
If the collapsing core of a massive star has more than , what object forms whose gravity is so strong that not even light can escape?
A black hole.
What stage of life is our sun in
main sequence
What factor primarily determines the temperature and luminosity of a newly formed star?
Mass
What region of the H–R diagram represents stars that have exhausted hydrogen in their cores and expanded while cooling at the surface?
The red giant
What process causes a white dwarf to gradually dim and cool over billions of years, eventually becoming a “dead” star?
It radiates away its leftover heat
What process stops inside a massive star once it develops an iron core, causing the star to collapse?
Fusion stops
Closet star to earth
sun