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Unformatted text preview: 1 Todays Lecture: purpose & goals Stellar Evolution: Inter s te ll ar Ga s & the B i rth of S tar s AST 1002 Planets, Stars and Galaxies 1) Review the Properties of Stars 2) Interstellar Medium & Intro to Stellar Evolution molecular clouds emission & dark nebulae Bok globules Protostars Herbig-Haro objects 3) Lifetimes of Stars 4) Split Class: Springtime in the Universe (planetarium) Eagle Nebula i n S erpen s hot young star cluster O, B, A, F, G, K, M HR diagrams : E i nar Hertz s prung (Denmark) & Henry Norr i s Ru ss e ll (U . S . ) Plotted luminosity vs temperature All stars can be plotted on it. 90% of all stars are Main Sequence stars burning hydrogen to form helium in their cores. Surface temperatures : 2500K ~50,000K (core temps. All over 10,000,000K) Luminosities : 10-4 10 6 times the Sun Size : 0.01 ~2000 times the Sun Masses : 0.08 ~150 times the Sun Most stars less massive , smaller , cooler , and dimmer than Sun!! Mass-Luminosity relation L = M 3.5 i n mu l t i p l e s of the s un s l um i no s i ty and ma ss Review: Stellar properties Blue Giants white dwarves Red SuperGiants and Red Giants Sun red dwarves More massive less massive larger smaller Stellar Nurseries: Inter s te ll ar Ga s C l oud s-- Or i on 2 Large clouds Cold enough (T ~10 K...
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