Characteristics of stars

GENERAL CHARACTERISTICS Stars – Huge Masses of Gas Mainly Hydrogen and helium Energy from Nuclear Fusion Constellations – groups of stars in night sky Light –Year – distance light travels in one year Parallax – apparent change in position Apparent Magnitude – Brightness seen from Earth Actual Magnitude – How bright the star is GENERAL CHARACTERISTICS

DIFFERENT TYPES OF STARS HERTSPRUNG-RUSSELL DIAGRAM Compares Brightness of star to Surface Temperature and Color Main Sequence – Most stars are this Giants and Super Giants – Extremely large stars near the end of their life White Dwarfs – faint glow of star after it has burnt out Black Holes – not on diagram Death of really massive Stars DIFFERENT TYPES OF STARS

LIFE-CYCLE OF STARS Nebula  Protostar Main Sequence Life Span determined by fuel More Mass  shorter life Red Giant or Supergiant White Dwarf  Black Dwarf Supernova  Neutron Stars & Black Holes LIFE-CYCLE OF STARS

ODDS AND ENDS GOLDILOCKS CONDTION GALAXY – huge clusters of stars Narrow range of conditions that make life on Earth possible – “Just Right” Water, temperature, gravity etc. GALAXY – huge clusters of stars Classified by shape: Spiral, Elliptical, Irregular Milky Way – our galaxy; spiral BIG BANG THEORY Scientific Theory that explains how the universe formed from an enormous explosion 10 to 15 billion years ago Movement of Galaxies supports theory ODDS AND ENDS