Galaxy Forum USA - Galactic matter cycles

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Galaxy Forum USA - Galactic matter cycles

  1. 1. The Galactic Matter Cycle and Star Formation Randolf Klein The Galactic Matter Cycle and Star FormationISMGalactic MatterCycleDying Stars Randolf Kleinlow-masshigh-massSummary Space Sciences Laboratory & Dept. of Physics UC BerkeleyStar FormationSummary July 4, 2010 Galaxy Forum USA The Tech Museum San Jose, CA
  2. 2. The Galaxy The Galactic Matter Cycle and Star Formation Randolf KleinISMGalactic MatterCycleDying Starslow-masshigh-massSummaryStar FormationSummary Dark clouds in front of the Galactic Center from wikipedia – Milky Way
  3. 3. A small dark nebula: Barnard 68 The Galactic Matter Cycle Looking through an isolated dense core in the near infrared. and Star Formation Randolf KleinISMGalactic MatterCycleDying Starslow-masshigh-massSummaryStar FormationSummary
  4. 4. Orion in the Far Infrared The Galactic Matter Cycle and Star The constellation Formation Randolf Klein Orion harbors manyISM bright and darkGalactic MatterCycle nebulae.Dying Starslow-masshigh-mass They are anotherSummaryStar Formation telltale sign for matterSummary between the stars. But the whole picture emerges at far infrared wavelengths . . . c T. Credner & S. Kohle, AlltheSky.com
  5. 5. Orion in the Far Infrared The Galactic Matter Cycle and Star Formation Randolf KleinISMGalactic MatterCycleDying Starslow-masshigh-massSummaryStar FormationSummary
  6. 6. The Interstellar Medium – ISM The Galactic Matter Cycle and Star A few facts: Formation Randolf Klein The space between the stars is filled with gas and dust.ISM The average density is one atom per cm3 .Galactic Matter In this room, there are 6 · 1019 atoms per cm3 .CycleDying Stars The average temperature is a few 1000 Kelvin (similar tolow-mass stellar surfaces). But the temperature ranges from a fewhigh-massSummary million Kelvin down to 10 Kelvin. The gas con be ionized (H+ ), neutral (H), or molecular (H2 )Star FormationSummary depending on the temperature. About one percent in mass of the ISM are very fine (∼ 1µm) dust grains. The composition is similar to sand and soot. This little amount of dust is very important for the optical and chemical properties of the ISM.
  7. 7. The Galactic Matter Cycle The Galactic Matter Cycle and Star Formation Randolf Klein Question?ISM Where does the gas and dustGalactic MatterCycleDying Stars come from?low-masshigh-massSummary Stars fuse hydrogen and helium into heavierStar FormationSummary elements, but how do these elements end up between the stars.
  8. 8. The Galactic Matter Cycle The Galactic Matter Cycle and Star Formation Randolf Klein Question?ISM Where does the gas and dustGalactic MatterCycleDying Stars come from?low-masshigh-massSummary Stars fuse hydrogen and helium into heavierStar FormationSummary elements, but how do these elements end up between the stars. But where do stars come from?
  9. 9. The Galactic Matter Cycle The Galactic Matter Cycle and Star Formation Randolf Klein Question?ISM Where does the gas and dustGalactic MatterCycleDying Stars come from?low-masshigh-massSummary Stars fuse hydrogen and helium into heavierStar FormationSummary elements, but how do these elements end up between the stars. But where do stars come from? Let’s look at the Galactic Matter Cycle. . .
  10. 10. The Galactic Matter Cycle The Galactic Matter Cycle Stellar and interstellar Matter get recycled and Star Formation Randolf KleinISMGalactic MatterCycleDying Starslow-masshigh-massSummaryStar FormationSummary http://hea-www.cfa.harvard.edu/CHAMP/EDUCATION/PUBLIC/starlifecycles pics.html Left: low-mass/sun-like stars – planetary nebulae Right: high-mass stars – supernovae
  11. 11. Dying Low-Mass Stars The Galactic Matter Cycle The Fate of the Sun: and Star Formation In a few billion Randolf Klein years, the sun’sISM core will run outGalactic MatterCycle of hydrogen.Dying Starslow-mass The nuclear firehigh-massSummary will continue toStar Formation burn in a shellSummary causing the sun to swell enormously. The outer layers will be blown into space.
  12. 12. Dying Low-Mass Stars The Galactic Matter Cycle and Star The Next Stage: a Proto-Planetary Nebula Formation Randolf KleinISMGalactic Matter Here, a sun-likeCycle star illuminatesDying Starslow-mass the sheddedhigh-mass outer layers as itSummaryStar Formation contracts andSummary heats up. It will become a Planetary Nebula.
  13. 13. Planetary Nebulae Gallery The Galactic Matter Cycle and Star Formation Randolf KleinISMGalactic MatterCycleDying Starslow-masshigh-massSummaryStar FormationSummary
  14. 14. Planetary Nebulae Gallery The Galactic Matter Cycle and Star Formation Randolf KleinISMGalactic MatterCycleDying Starslow-masshigh-massSummaryStar FormationSummary
  15. 15. Planetary Nebulae Gallery The Galactic Matter Cycle and Star Formation Randolf KleinISMGalactic MatterCycleDying Starslow-masshigh-massSummaryStar FormationSummary
  16. 16. Planetary Nebulae Gallery The Galactic Matter Cycle and Star Formation Randolf KleinISMGalactic MatterCycleDying Starslow-masshigh-massSummaryStar FormationSummary
  17. 17. Dying High-Mass Stars The Galactic Matter Cycle η Carinae, and Star Formation This very massive Randolf Klein star (100 M ) isISM running out ofGalactic MatterCycle hydrogen and startsDying Stars to fuse heavierlow-masshigh-mass elements.SummaryStar Formation It burns in manySummary shells violently bursting off its outer layers. And the end is also much more violently. . .
  18. 18. Supernovae The Galactic Matter Cycle and Star Formation Randolf KleinISMGalactic MatterCycleDying Starslow-masshigh-massSummaryStar FormationSummary c NSF
  19. 19. Supernovae Remnants The Galactic Matter Cycle and Star Formation Randolf KleinISMGalactic MatterCycleDying Starslow-masshigh-massSummaryStar FormationSummary
  20. 20. Supernovae Remnants The Galactic Matter Cycle and Star Formation Randolf KleinISMGalactic MatterCycleDying Starslow-masshigh-massSummaryStar FormationSummary
  21. 21. Supernovae Remnants The Galactic Matter Cycle and Star Formation Randolf KleinISMGalactic MatterCycleDying Starslow-masshigh-massSummaryStar FormationSummary
  22. 22. Summary of Stellar Evolution The Galactic Matter Cycle and Star Formation Randolf KleinISM Dying starsGalactic Matter replenish theCycle interstellarDying Starslow-mass medium withhigh-massSummary gas and dust.Star Formation Massive starsSummary enrich it with heavy elements. http://chandra.harvard.edu/edu/formal/stellar ev/
  23. 23. The Galactic Matter Cycle The Galactic Matter Cycle and Star Formation Question? Randolf Klein What happens to the gas and dust?ISMGalactic MatterCycle GravityDying Starslow-masshigh-massSummary Under its own gravity, the gas and dustStar Formation concentrates in clouds.Summary The gas cools and becomes molecular. More cooling by dust and molecular radiation allows the gas to collapse more and more. Stars form in the densest cloud cores.
  24. 24. How to form a low-mass star? The Galactic Matter Cycle and Star Formation Dense cores Gravitational collapse Randolf Klein in molecular cloudISMGalactic MatterCycleDying Starslow-masshigh-massSummaryStar FormationSummary 1 pc 10 000 AU Design: Michiel Hogerheijde (nach Shu, Adams & Lizano 1987, ARAA 25, 23) t = 0 yr
  25. 25. How to form a low-mass star? The Galactic Matter Cycle and Star Embedded protostar Pre−main sequence star Formation Accretion, Jet, Outflow Jet, Outflow Randolf Klein . ¨ISMGalactic MatterCycleDying Starslow-masshigh-massSummaryStar FormationSummary Core ~ 8000 AU Disk ~ 80 AU 100 AU 4 5 5 6 t ~ 10 −10 yr t ~ 10 −10 yr Design: Michiel Hogerheijde (nach Shu, Adams & Lizano 1987, ARAA 25, 23)
  26. 26. How to form a low-mass star? The Galactic Matter Cycle and Star Pre−main sequence star Main sequence star Formation Planet formation in disk with planetary system Randolf KleinISMGalactic MatterCycleDying Starslow-masshigh-massSummaryStar FormationSummary 100 AU 50 AU 6 7 7 t ~ 10 −10 yr t >10 yr Design: Michiel Hogerheijde (nach Shu, Adams & Lizano 1987, ARAA 25, 23)
  27. 27. Disks around Young Stars The Galactic Matter Cycle and Star Formation Randolf KleinISMGalactic MatterCycleDying Starslow-masshigh-massSummaryStar FormationSummary
  28. 28. Disks launch Jets The Galactic Matter Cycle and Star Formation Randolf KleinISMGalactic MatterCycleDying Starslow-masshigh-massSummaryStar FormationSummary scale bar = 1000 AU
  29. 29. Star and Planet Formation The Galactic Matter Cycle and Star Formation The forming stars radiate Randolf Klein energy gained mainly fromISM contraction.Galactic MatterCycle They are contracting tillDying Stars their central temperaturelow-masshigh-mass reaches 10,000,000 K.SummaryStar Formation Then hydrogen fusionSummary starts and a normal, a Star formation is very inefficient. main-sequence star star is Only a few percent of the gas in a born. molecular cloud is converted into The cycle is closed. stars and planets.
  30. 30. Summary The Galactic Matter Cycle and Star Formation The space between the stars is filled with gas and dust: Randolf Klein the Interstellar Medium or ISM.ISM The ISM can be studied at other wavelengths than theGalactic Matter visible light.CycleDying Stars The life of stars cycles matter in and out of the ISM.low-masshigh-mass Dying stars inject a (large) fraction of their mass into theSummaryStar Formation ISM.Summary Massive stars enrich the ISM with heavy elements. In the densest molecular clouds, a few percent of the ISM gets transformed into stars and planets. We are all made of star dust! Then jets, outflows, and supernovae disperse the cloud.
  31. 31. What is more: Massive Star Cluster The Galactic Matter Cycle and Star We further know: Formation Randolf Klein All stars form inISM clusters.Galactic MatterCycle While the sunDying Stars formed alow-masshigh-mass Supernova went offSummary close by – < 1.6 pcStar Formation away. (Looney at al. 2006)Summary The Sun forming close to massive stars is likely, but makes things complicated. Rosette Nebula
  32. 32. Massive Star Cluster The Galactic Matter Cycle and Star Formation Randolf KleinISMGalactic Matter Strong stellarCycleDying Stars winds erode thelow-mass molecular cloud thehigh-massSummary massive starStar Formation formed from andSummary other dense cores around it.
  33. 33. Simulation of a Turbulent Cloud Collapsing The Galactic Matter Cycle and Star Formation Mass 50 M Randolf Klein Size 0.3 pcISM Duration 266,000 yrGalactic MatterCycle Forms 50 stars and BrownDying Starslow-mass Dwarfshigh-massSummaryStar Formation 100000 CPU hours on upSummary to 64 processors.In total 1016 FLOP. Matthew Bate, University of Exeter (2002)

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