Original Caption: "Born from nebulae of gas and interstellar dust, stars like our Sun (those less than ∼ 8 M_☉) spend most of their lifetime in a slow nuclear burning of their primary nuclear fuel hydrogen (H) into the heavier element helium-4 (He-4). They are then main-sequence stars. After leading this bright and shiny life for several billion years, their fuel is almost exhausted in their core and they start swelling, pushing the outer layers away from what has turned into a small and very hot core. They are now post-main-sequence stars and most of their post-main-sequence lifetime is spent as red giants which are typically of order 1 astronomical unit (AU) and have cool photospheres, and so look red. All red giants exhibit a slow oscillation in brightness due to their rhythmic "breathing" in and out???, and one third of them are also affected by additional, slower and mysterious changes in their luminosity???. After this rapid and tumultuous phase of their later life, these post-main-sequence stars do NOT end in dramatic explosions (i.e., as supernovae), but die peacefully as planetary nebulae, blowing out everything, but tiny compact remnants known as white dwarfs." (Moderately edited.)
Credit/Permission: ©
ESO/S. Steinhoefel,
2009 /
Creative Commons
CC BY-SA 3.0.
Image link: Wikipedia:
File:Diagram of the life of Sun-like stars.jpg.
Local file: local link: stellar_evolution_overview.html.
File: Star file:
stellar_evolution_overview.html.