logging in or signing up Chapter 30 Stars Abhil Download Post to : URL : Related Presentations : Share Add to Flag Embed Email Send to Blogs and Networks Add to Channel Uploaded from authorPOINTLite Insert YouTube videos in PowerPont slides with aS Desktop Copy embed code: Embed: Flash iPad Copy Does not support media & animations WordPress Embed Customize Embed URL: Copy Thumbnail: Copy The presentation is successfully added In Your Favorites. Views: 641 Category: Entertainment License: All Rights Reserved Like it (1) Dislike it (0) Added: October 07, 2007 This Presentation is Public Favorites: 0 Presentation Description No description available. Comments Posting comment... Premium member Presentation Transcript Chapter 30: Stars: Chapter 30: Stars Mr. NolenOur star: The Sun: Our star: The Sun Properties Made of He and H and contains 99% of all mass in the solar system The center is 1x107 K Slide3: Layers of the sun Photosphere: inner layer, visible layer of the sun, 5800 K Chromosphere: 2500km thick and temps of 30000K Corona: several million km thick and temps of 1-2 million degrees k Solar Wind- Gas flows outward from the corona at high speeds. When collide with planets cause aurorae (northern lights)Slide4: Solar Activities Sunspots- cooler spots on sun due to magnetic fields Solar flares- violent eruptions and radiation with sunspots. When they hit earth they interfere with satellites and communications. Solar activity has caused small climate changes over the course of history Slide5: How stars work- Fusion Process of combining of lightweight nuclei, such as hydrogen, into heavier nuclei In stars helium is the product of hydrogen fusing Our suns rate of fusing shows that it it is about halfway through its lifetime, with about another 5 billion years left. Energy produced in sun goes through 2 zones radiative zone and convective zone.Slide6: Constellations A. 88 groups of stars named after animals, mythological characters, or everyday objects. Circumpolar= stay in sky B. Although they appear close in the sky, stars are very far apart (closest star to the sun is 4.6 LY away) C. 3 systems: 1) open cluster- not densely packed. 2) globular cluster- densely packed. 3) Binary stars- 2 that are in orbit of each other. Slide7: 6. Distances of Stars A. ly(9.461 × 1012 km) and parsecs(3.086 × 1013 km) B. Parallax- apparent shift in position of an object caused by the motion of the observer. Caused by the orbit of earth. Slide8: 7. Properties of Stars A. Apparent Magnitude- how bright a star appears to be. Negative numbers mean brighter. Doesn’t take into account distance. B. Absolute Magnitude- the brightness an object would have if it were placed at a distance of 10 pc. Actual brightness. C. Luminosity- energy output from the surface of a star per second. Sun’s luminosity is about 3.85 × 1026 Watts. Slide9: 8. H-R Diagrams A. demonstrates the relationship between mass, luminosity, temperature, and the diameter of stars B. The main sequence represents about 90 percent of stars C. Red giants are large, cool, luminous stars, while white dwarfs are small, dim, hot stars Slide10: 9. Star Life Cycles A. As stars age they convert one element into another. When that happens its density increases, its temperature rises, and its luminosity increases. B. Star formation begins when the nebula (gas cloud) collapses on itself as a result of its own gravity, the collapsing rotation forces it into a disk shape C. A protostar forms at the center of the disk that will become a new starSlide12: D. Sun life Cycle 1. When sun fuses all H to He the outer layers expand and cool till the sun becomes a red giant. 2. As a red giant the core get hot and the helium begins to fuse into carbon until there is no He left. 3. The star isn’t big enough for the C to react to a nebula forms around the star and the core remains as a white dwarf of CSlide13: E. Life Cycle of Stars bigger than the Sun 1. 8-20x size of sun. Stars get bigger and bigger as they expand through their life and become a supergiant. 2. After fusion there cores can’t stand the pressure and they collapse into a neutron star which causes a supernova- a massive explosion of outer portion of a star 3. 20+ times the size of sun. The star will collapse and collapse on itself forever. Making itself so small that even light can’t pass through- a blackhole You do not have the permission to view this presentation. In order to view it, please contact the author of the presentation.