Questions:
1. The most common type of star in the universe is the main sequence star. The name comes from the fact that in a graph of a star’s brightness versus its colour, main sequence stars lie along a prominent diagonal band. What is this graph called?
2. The abundance of elements produced in a star increases up to the atomic number of X, and then declines. This is partly because X is the lightest element for whose nuclear fusion produces less energy than it consumes. Name X.
3. When a star of low to medium mass runs out of helium, it will need to fuse carbon, which requires a core temperature of at least 1 billion K. If the star lacks this temperature, its outer layers will be shed, leaving behind an inert core. What is this core called?
4. When the core of a very heavy star collapses due to its own gravity, it can form a neutron star. What is the upper limit of the mass of a neutron star called?
5. For some very heavy stars, scientists have predicted an unusual kind of supernova when they run out of fuel. In this event, the star undergoes a partial collapse, kickstarting a thermonuclear reaction that completely blows up the star. What is such a supernova called?
Visual:
Name this nebula, at whose centre lies a famous pulsating neutron star that greatly advanced scientists’ understanding of how big stars die.
Answers:
1. Hertsprung-Russell diagram
2. Iron
3. White dwarf
4. Tolman-Oppenheimer-Volkoff limit
5. Pair-instability supernova
Visual: Crab Nebula
