UCL Science Centre ‘Science Lectures for Schools’ 2010 Nov 26. Ian Howarth http://www.star.ucl.ac.uk/~idh/. The Hertzsprung-Russell Diagram: Stars Struggle Against Gravity. The Hertzsprung-Russell Diagram: Stars Struggle Against Gravity. What’s this got to do with supernovae? - PowerPoint PPT Presentation
Text of Ian Howarth star.ucl.ac.uk/~idh
Ian Howarthhttp://www.star.ucl.ac.uk/~idh/UCL Science CentreScience Lectures for Schools 2010 Nov 26
The Hertzsprung-Russell Diagram: Stars Struggle Against GravityThe Hertzsprung-Russell Diagram: Stars Struggle Against Gravity
Whats this got to do with supernovae?
Normal stars are in a state of equilibrium between gas pressure pushing outwards and gravity pulling inwards (just like our atmosphere).
However, to maintain the gas pressure we need a heat source. When that source is exhausted, gas pressure is removed, and the star will collapse.
A big star will undergo a big collapse: a supernova
SN 1994D in NGC 4526
RCW 86: remnant of Guest Star from 185SN 1006: brightest star ever seen1054, Crab Nebula
Tychos Star(1572)De nova [et nullius aevi memoria prius visa] stella
Keplers Star (1604)
SN 1885 in M31
Fritz Zwicky (1898-1974)(coined Supernova)
SN 1937ANGC 4157
~1x107KNuclear burning: HHe
Helium burning:The continuing struggle against gravity...Carbon burning:~108K~109K