Download Massive Star (10 to 15 times the size of our Sun) Nuclear Fusion

3/21/10 Alex Panka March 1, 2010 Astronomy Writing  
Massive Star (10 to 15 times the size of our Sun)  
Nuclear Fusion balances Gravitational Pull  
No fusion => no force to balance gravity  
Star collapses => Supernova  
Remnants of star shrink to infinite density  
Black Hole 1 3/21/10   Where is the proof?   Research team observed a star closely orbiting the mysterious object   The star, known as S2, followed a small, extended orbit (e = 0.87) with a period of only 15 years   The star got within 17 light hours of the object (3 times the Sun‐
Pluto distance) traveling at 5,000 kilometers per second (200 times the speed of the Earth around the Sun) S2 Orbiting Super‐Massive Black Hole  
Using orbital technique, mass can be determined from a single stellar orbit with high accuracy  
2.6 Million Solar Masses 2 3/21/10   Theory:   the immense gravitational pull from the black hole should tear apart the molecular clouds, removing the necessary condition for star formation.   Two Possibilities:   the stars formed elsewhere and migrated to the black hole   the star formed near the black hole under unusual circumstances   Two Scenarios:   10^4 solar mass molecular cloud falling toward a 10^6 solar mass black hole   10^5 solar mass molecular cloud falling toward a 3*10^6 solar mass black hole Molecular Cloud Approaching a Black Hole  
Scenario 1: The star formation of the 10^4 M molecular cloud formed 498 stars  
Scenario 2: The larger 10^5 M cloud formed 198 stars Conclusion: • Simulations show molecular cloud can form an eccentric disk around a super‐
massive black hole • Although tidal forces will disrupt the cloud, it does not destroy the small‐scale structure that seed star formation. 3 3/21/10  
Fact:   Galaxies surrounding bulge of old stars always contain about 700 times the black hole’s mass  
Tests:   Team of astronomers study distant black holes at red‐shift 6.42 (870 million years after Big Bang)   The bulges were only 30 times more massive than the hole   Black holes come first and somehow grow galaxies around them.   Super‐massive black holes can trigger the formation of stars, thus ‘building’ their own host galaxies.   This connection could also explain why galaxies hosting larger black holes have more stars. 4 3/21/10   Formation of black hole is closely entwined with that of its galaxy  
The Evidence   Growing black holes = more massive galaxies  
Weak black hole growth = old elliptical galaxies (no more star formation)  
Strong black hole growth have similar mass and structure, but show evidence for recent significant star formation.  
As the rate of black hole growth increases, so does the amount of recent star formation   Much more to learn   Properties within the Black Hole   Many Theories   Time Warps? 5 3/21/10  
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Schilling, Govert ‘Star Speeds Around Milky Way’s Black Hole’. Sky and Telescope http://www.skyandtelescope.com/news/3306776.html Genzel, Reinhard ‘Surfing a Black Hole’ European Southern Observatory. Press Release 16 October 2002 http://www.eso.org/public/news/eso0226/ Author Anonymous ‘Black Holes and their Host Galaxies Grow Together’ 16 July 2003 http://www.redorbit.com/news/space/7419/
black_holes_and_their_host_galaxies_grow_together/index.html Beatty, Kelly ‘Star Studded Black Holes’ Sky and Telescope. 22 August 2008 http://www.skyandtelescope.com/community/skyblog/newsblog/27275409.html Naeye, Robert ‘Black Holes First, Galaxies Second’ Sky and Telescope. 8 January 2009 http://www.skyandtelescope.com/community/skyblog/newsblog/37287354.html Carilli, Riechers ‘Black Holes Lead Galaxy Growth, New Research Shows’ Press Release, Nation Radio Astronomy Observatory, 6 January 2009 http://www.nrao.edu/pr/2009/bhbulge/ Author Anonymous ‘Black Holes: A Mighty Void’ National Geographic http://science.nationalgeographic.com/science/space/universe/black‐holes‐article.html Bonnell, A. ‘Star Formation Around Super‐massive Black Holes’ Science. 22 August 2008 www.sciencemag.org Schodel, R. ‘Closest Star Seen Orbiting the Super‐massive Black Hole at the Centre of the Milky Way’ 18 October 2002 arXiv:astro‐ph/0210426v1 6