Take out a piece of paper Write down one thing you remember seeing with binoculars or the telescope at Ki: Peak Write down one ques=on you have about the trip or something we saw Death Adulthood Old age Childhood Death leads to raw materials for new stars Death Adulthood Old age Childhood Death leads to raw materials for new stars Main sequence Birth of stars Death of stars Main sequence Birth of stars Death of stars Main sequence Main sequence If star was < 8 x Mass of sun Birth of stars If star was > 8 x Mass of sun but < 25 x Mass of sun Main sequence If star was > 25 x Mass of sun Main sequence If star was < 8 x Mass of sun Birth of stars If star was > 8 x Mass of sun but < 25 x Mass of A star’s ul=mate fate depends on its mass sun Main sequence If star was > 25 x Mass of sun What is mass? What has a larger mass? (A) a kilogram of feathers (B) a kilogram of lead? What weighs more? (A) a pound of feathers (B) a pound of lead? What weighs more? (A) a pound of feathers (B) a pound of lead? 1 kg of mass means the same mass as this object: Cast iron 1 kg of mass means the same mass as this object: Cast iron 1 kg of mass means the same mass as this object: Pla=num iridium alloy The mass of the sun is approximately 30
10 kg 1,000,000,000,000,000,000,000,000,000,000 kg So astronomers invented a new unit called a “solar mass”. This is the mass of the sun, or approximately 1030 kg Look at the posi=on of the star Betelgeuse on the HR diagram below. If you could place Betelgeuse opposite the sun on a balance scale, what would happen? Look at the posi=on of the star Vega on the HR diagram below. If you could place Betelgeuse opposite the sun on a balance scale, what would happen? Look at the posi=on of the star Vega on the HR diagram below. If you could place Betelgeuse opposite the sun on a balance scale, what would happen? What is the life cycle for a star like the sun? Main sequence If star was < 8 x Mass of sun Birth of stars If star was > 8 x Mass of sun but < 25 x Mass of sun Main sequence If star was > 25 x Mass of sun Computer simula=on of the life cycle of a 1 Solar Mass star HR Diagram Simulated image What is the life cycle for a star two =mes the mass of the sun? Main sequence If star was < 8 x Mass of sun Birth of stars If star was > 8 x Mass of sun but < 25 x Mass of sun Main sequence If star was > 25 x Mass of sun Computer simula=on of the life cycle of a 2 Solar Mass star HR Diagram Simulated image What is the life cycle for a star 15 =mes the mass of the sun? Main sequence If star was < 8 x Mass of sun Birth of stars If star was > 8 x Mass of sun but < 25 x Mass of sun Main sequence If star was > 25 x Mass of sun Computer simula=on of the life cycle of a 15 Solar Mass star HR Diagram Simulated image What is the life cycle for a star 30 =mes the mass of the sun? Main sequence If star was < 8 x Mass of sun Birth of stars If star was > 8 x Mass of sun but < 25 x Mass of sun Main sequence If star was > 25 x Mass of sun Computer simula=on of the life cycle of seven different extremely massive stars Life cycle of a cluster of stars born at the same =me 10,000 stars with a range of masses Look at the posi=on of the star Betelgeuse on the HR diagram below. If you could place Betelgeuse opposite the sun on a balance scale, what would happen? Look at the posi=on of the star Vega on the HR diagram below. If you could place Vega opposite the sun on a balance scale, what would happen? Look at the posi=on of the star Barnard’s star on the HR diagram below. If you could place Barnard’s star opposite the sun on a balance scale, what would happen? Suppose you wanted to determine the mass of some random star in the sky. How would you do it?