PPT-Chapter 11 The Formation and Structure of Stars

Guidepost In this chapter you will consider how the interstellar medium condenses into stars and what the conditions inside stars must be like How do stars form What is the evidence that stars are forming now. Richard B. . Larson. Yale University. Conclusions. Compact objects such as stars and black holes generally form in larger systems such as binaries, multiple systems, star clusters, or galaxies.. Gravitational interactions in these larger systems play a major role in the formation of compact objects by transporting angular momentum.. (Resolved by Galileo). Milky Way:. Galactic Structure and Dynamics. Milky Way has spiral structure. . Galactic Bulge surrounds the Center. . Powerful radio source Sagittarius A at Center. C. ontains Super-Massive Black Hole . What force makes stars? . Gravity!. Out of what? Interstellar gas and dust. But this stuff is VERY low density… a dense area may have ~100 atoms / cm. 3. . Compare that the air you’re breathing… ~10. William Herschel’s map of the Milky Way based on star counts. In the early 1800’s William Herschel, the man who discovered the planet Uranus, tried to understand the shape of the Milky Way by counting stars. He counted how many stars there were in each of dozens of different directions and then plotted the count versus direction. . Christopher W. Ashcraft M.S., M.Ed.. Big Bang vs. Creation. Origin of Stars. Solar System: Evidence of Design. Age of the Cosmos. Are we being told all the evidence or just selected information to support a particular idea?. 23. vs. .. 1. First spiral nebula found in 1845 by the Earl of . Rosse. . Speculated it was beyond our Galaxy.. 1920 - "Great Debate" between Shapley and Curtis on whether spiral nebulae were galaxies beyond our own. Settled in 1924 when Edwin . 23.1 Our Parent Galaxy. 23.2 Measuring the Milky Way. Early “Computers”. 23.3 Galactic Structure. 23.4 The Formation of the Milky Way. 23.5 Galactic Spiral Arms. Density Waves. 23.6 The Mass of the Milky Way Galaxy. . Why Spiral Arms?. Why not just an undisturbed uniform disk?. Well, remember that . the innermost parts rotate faster than those farther out.. This suggests . one . obvious possibility: some linear structure forms, then . Revision . lecture. Lecture slides available in . powerpoint. and . pdf. from. www.star.le.ac.uk. /~. mbu. /. lectures.html. Everything taught in the course is examinable…... However, here is a crib sheet of what to focus on. Insights from recent surveys. Gaspard . Duchêne. (UC Berkeley, Obs. Grenoble). © NASA/JPL/Caltech. Planets in multiple systems?. © . LucasFilm. Ltd.. They must exist!. Planets in multiple systems!. and Future of Binary Stars. Max Moe (University of Arizona). Einstein Fellows Symposium . –. Oct. 12, 2017. Formation of Very Close Binaries. ~80% of solar-type binaries . with P. inner. . < 7 days have tertiary companions. .. 1. First spiral nebula found in 1845 by the Earl of . Rosse. . Speculated it was beyond our Galaxy.. 1920 - "Great Debate" between Shapley and Curtis on whether spiral nebulae were galaxies beyond our own. Settled in 1924 when Edwin . The Last Epoch Cosmic Structure Formation Today we have a matter-dominated universe ruled by the force of gravity. Slight variations in density produces formation regions for stars and galaxies. 1 st Effects . of hot halo gas . during . distant galaxy-galaxy encounters. Jeong. -Sun Hwang (Kyung . Hee. Univ.). & . Changbom. Park (KIAS). on the star formation & mass transfer . Poster #8 ⇒.