luminositysburns/...white dwarf!• neutron star!• black hole †ejected remnant!• planetary...
Post on 15-Feb-2021
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• Luminosity is the total power output of an object!
• Units of luminosity are energy/sec or Watt• The luminosity of the sun is
Luminosity
L! = 3.826 × 1026
W
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*Compact Remnant! • White Dwarf! • Neutron Star! • Black Hole
†Ejected Remnant! • Planetary Nebula! • Supernova Remnant
ISM
Protostar
MS Star
Post MS Star
Brown Dwarf
CR* ER†
The life-cycle of stars
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ISMThe interstellar medium is
mostly Hydrogen!
This radio image shows the distribution of hydrogen in center of our galaxy.
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Star forming regions
Protostars are often obscured by dust.
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Can “see” through dust in the infrared!
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Main Sequence Stars
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Main Sequence Stars
• “burn” hydrogen in their cores (PP chain)
• lifetime depends on the star’s mass
t∗ =1010 years
(M/M")2
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large-mass short-lifetime stars
small-mass long-lifetime stars
Lifetime of Main Sequence Stars
τms ≈1010 years
(M/M!)2
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Nuclear Binding Energy
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Hydrogen Fusion (PP chaine)
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Post MS evolution of star1M!
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Planetary Nebula
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Nuclear Binding Energy
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Supernovae
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Post MS
White Dwarf & Planetary Nebula
Type II Supernova
Neutron Star
Black Hole
Increasing star mass
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*Compact Remnant! • White Dwarf! • Neutron Star! • Black Hole
†Ejected Remnant! • Planetary Nebula! • Supernova Remnant
ISM
Protostar
MS Star
Post MS Star
Brown Dwarf
CR* ER†
The life-cycle of stars
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