NATS 1880 Lecture Notes - Lecture 11: Gliese 229, Circumbinary Planet, Brown Dwarf
25 Jun 2017
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Chapter 11; extrasolar planets -> nature + potential habitability. Star: ball of gas powered by nuclear fusion & held together by own gravity. Older stars -> gas cloud helium & hydrogen. New stars -> h&h + heavier elements/ star stuff -> important for planet formation. 2%: heavier elements in our solar system (ice/rock/metal) formed our planets. * spectral type: obafgkm (o,b - white/blue = hottest & m = coolest) - [obs. from far] Our sun: g star (g2 exact, since g class is divided up to g9) Previous spectral system: ranked by prominence of dark lines (a, b, etc. ) Luminosity: brightness -> bigger = hotter = brighter from energy of higher fusion rate. Mass: 8% mass of our star - 150 x mass of our star. Brown dwarfs: star-like objects, but below minimum mass (unable to sustain heat) Rst brown dwarf: gliese 229b (gliese 229a is the m star beside it*)
