H-R diagram shows age of M80 is about 12 billion years. Many have not had time to age off the main sequence :Ġ.74 M sun "lives" 20 billion years as main sequenceĬore temperature rises to 600 million K (6 x10 8 K)įusion of even heavier elements occurs, as star gets hotter and hotter Lower Mass Stars (less than a Solar Mass) eventually cools to become a black dwarf.core burning stops / shell burning continues.Photograph nearly one hundred white dwarfs in the globular cluster M4 Image of M4 as seen from ground-based telescope.this is enough time for the lighter stars to evolve into white dwarfs.globular clusters are old: > 10 billion years.There should be many white dwarfs in globular clusters Observation of White Dwarfs by the Hubble Space Telescope Sirius B radius is smaller than Earth, about 0.007 x R SUN If the mass is greater than 1.4 x M SUN, the electron pressure degeneracy cannot support the weight. If the mass is less than 1.4 x M SUN the electron degeneracy pressure holds up the star Very common (20,000 to 50,000 in the Milky Way)Įvolution Following Planetary Nebula Phase (solar mass star)Ĭhandrasekhar Limit is the Maximum mass for a white dwarf star (They look a bit like planets through small telescopes, but haveĮxpand for about 50,000 years before fading. These gases are ionized by star and glow. Push the outer envelope of the star to greater As the star expands, and helium shell burning proceeds,Ī series of helium-shell flashes cause the.White dwarf at center of planetary nebulaĭying low-mass star ejects its outer layers of gas. Planetary Nebula is ejected (25 - 60% of mass ejected)Įxpands for about 50,000 yrs before fading Helium core burns into carbon and oxygen and eventuallyĬarbon core formed at the center of the star Helium core collapses and star expands into Red Giant Tightly packed, but there is a limit to the packing) No two electrons can occupy the same space
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