QUO Fast Radio Bursts

Dangerous Universe E2: Star Slaying

November 08, 2021 Season 3 Episode 2
QUO Fast Radio Bursts
Dangerous Universe E2: Star Slaying
Show Notes


  • What is a star? 
    • Ball of hydrogen
    • Balance of fusion and gravity (talk by Connor Stone on elements in the universe)
    • Radiation transfer, convection, radiation
    • From very small (a tenth of the mass of our sun) to very large (thousand times the mass of our sun)
  • What methods are there to destroy a star?
  • Wait for it:
    • Small stars potentially live for 1Trillion years or more (they burn their fuel much slowly and regulate their temperature much better)
    • Sun-like stars tend to puff out after ~10 billion years. Red giant phase, then planetary nebula and white dwarf.
  • Nearby white dwarf:
    • Having white dwarfs nearby can rip stars apart!
    • How close does a star need to be: It actually changes with time. If the two are close enough to each other to trade mass, it means at least part of the main star is in the “Roche limit
    • It is the same process that gives Saturn it's rings.
    • It is possible that these don’t always completely destroy the star and so it could happen multiple times.
  • Falling into a Black hole:
    • It’s not what you would immediately expect. Space is big and by comparison, stars and black holes are small, so the chance of them being in a head-on collision is miniscule. Instead a star will orbit the back hole and slowly get closer, or come in and just miss it, swinging around like a comet almost.
    • These are called tidal disruption events. The star comes within the roche limit and is torn apart.
    • Black holes are messy eaters, most of the star gets sloppily added to the accretion disk and eventually pushed away from the black hole.
    • Supermassive black holes at the centers of galaxies have eaten many stars this way.

Links to Science Outreach Material:

Special thanks to Colin Vendromin for the music, also thanks to Zac Kenny for the logo!