1 / 11

The Life Cycle of a Star

The Life Cycle of a Star. Upper Fifth Physics. In The Beginning…. Lots of gas and dust All this stuff gravitationally attracted Click picture for full news story. War between gravity and pressure.

brianna-sampson
Télécharger la présentation

The Life Cycle of a Star

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. The Life Cycle of a Star Upper Fifth Physics

  2. In The Beginning… • Lots of gas and dust • All this stuff gravitationally attracted • Click picture for full news story

  3. War between gravity and pressure • If the mass of gas is large enough, then the gravitational attraction of the particles will overcome the pressure and the cloud will contract

  4. Ignition! • As the cloud contracts, GPE is converted into KE. • Temperature of cloud is related to the average KE of the molecules. • Increase in KE ‘means’ an increase in temperature. • If temperature exceeds 15 million K, hydrogen fuses into helium and we have ignition!

  5. Just keep glowing… • Star continues to glow as long as there is sufficient hydrogen. • Battle between forces due to gravity and pressure continues but is stable. • Each second, the Sun converts 1 million kg of hydrogen in helium

  6. Running low on gas • Helium production continues until hydrogen runs out. • Helium fuses into other nuclei, but the process isn’t as efficient. • What happens next depends on the original mass of the star (click on a button) Great Links Little Star Big Star

  7. Little Star • Hydrogen cloud around hot central core drifts off • As last of hydrogen drifts off, big wind comes from surface of core • Wind distorts hydrogen cloud. • We have a ‘planetary nebula’ surrounding a white dwarf • White dwarf cools and fades away Return to ‘Running Low on Gas’

  8. Big Star • Star burns helium to other elements, which in turn can be fuses into heavier elements still.

  9. Large pop! • Iron doesn’t burn so eventually the fusion stops! • There is nothing to stop the gravitational pull of the nuclei on each other. • Iron core collapses in a second. • Resulting explosion is a supernova, visible between galaxies. • During this explosion, heavier elements are made (all elements in universe heavier than iron originally came from supernovae – including those inside you!

  10. What’s left? • If the star’s core was ‘small’ then a small spinning lump of neutrons called a neutron star is left. • If the star’s core was ‘large’ then a black hole is left. Back to ‘Running out of Gas’

  11. Great Links • NASA – for a more in depth description • More pretty pictures of • Stellar births • Stellar deaths • The science of black holes (odd stuff happens there)

More Related