it for astronomy presentation 2007 stars formation and evolution: interstellar medium to protostar...

IT for Astronomy Presentation 2007

StarsFormation and Evolution:Interstellar Medium to ProtostarProtostarsMain Sequence StarsGiants and DwarfsSupernovaThe Cycle restarts

IT For Astronomy Presentation 2007

Interstellar Medium to Protostar1. The ISM consists of gas and dust particles2. Regions may be viewed as clouds3. Some give off visible light, others weak radio waves4. Dense molecular clouds collapse5. Density is relative – virtual vacuum6. Colliding clouds can start gravitational compression7. Collapsing clouds fragment8. Molecules speed up and heat up9. Protostar starts to emit Infra Red radiation

IT For Astronomy Presentation 2007

Protostars

IT For Astronomy Presentation 2007

Main Sequence Stars The Hertzsprung-Russell

diagram is a way of categorising stars

It plots luminosity versus spectral colour which relates to temperature

Main sequence stars with a range of masses occupy a narrow band

IT For Astronomy Presentation 2007

Giants and Dwarfs Hydrogen fuel supply

exhausted in center – outer parts expand to form a Red Giant

Eventually outer parts shed to form a planetary nebula and leave a remnant White Dwarf

Larger mass stars can come to a worse end..

IT For Astronomy Presentation 2007

Supernova 1. Star explodes in

minutes.

2. May be visible to naked eye.

3. Remanant shrinks under own gravity.

4. May form Pulsar or

5. Black Hole.

IT For Astronomy Presentation 2007

The Cycle Restarts