Stars

Stars

Properties of stars
1. Brightness
  1. Absolute Brightness
    1. How bright a star actually is
  2. Apparent Brightness
    1. Decreases as distance increases
    2. How bright a star appears from Earth
2. Color and Temperature
  1. Surface Temperature determines color
  2. Blue = Hot
  3. Red = cool
3. Size and Mass
  1. Volume is based on temp and Abs. Brightness
  2. Gravitational interactions determine mass
  3. Positive correlation between Abs Brightness and mass
  4. Mass determines Life Cycle
4. Composition
  1. Primarily H and He
  2. Measure other elements with Spectral Analysis
    1. Absorption Lines
    2. Emission Lines
Determining Distance to Stars
1. Stars are lightyears away
2. Astronomers measure parallax
Life Cycle of Stars
1. Formation of Stars
  1. Solar Nebula Collabses
    1. Protostar forms at the center
      1. When Temperature and pressure is high enough, nuclear fusion begins
2. Main Sequence Stars
  1. Stars spend 90% of their life here
  2. Hydrogen Fusion int eh Core
3. Death of a Star
  1. When the star fuses all H in core into He
  2. Path Dependent on Mass
    1. Low/ Medium Mass Star
      1. Red Giant while fusing He
        Release gases - Planetary Nebula
        White Dwarf
    2. High Mass Star
      1. Mass more than 8x that of sun
      2. Fuses more elements than He
        because temp/pressure in core are high enough
        grow into supergiants
        Supernova - Violent explosion of dying star
        Ejects heavy elements into space
        Core collapses into Neutron Star
        Spinning Neutron Star = Pulsar
        Black Hole
        Gravity causes collapse beyond neutron star
        Come from extremely massive stars
        Surface Gravity so great not even EM waves can escape
      3. dies quickly bc it burns fuel quickly

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	Criado por Brianna Reilly aproximadamente 8 anos atrás