What makes massive stars (above about 8 solar masses) different from Sun-like stars after the main sequence?

They skip the red giant phase and go directly to supernovae They have enough mass and temperature to ignite successive rounds of fusion beyond helium — all the way to iron They fuse helium much more slowly than Sun-like stars They can fuse hydrogen and helium simultaneously in the same layer

Which element marks the end of energy-producing fusion in the core of a massive star?

Carbon — stars cannot fuse carbon under any conditions Oxygen — oxygen is too stable to be fused Gold — stars stop at gold because it is the heaviest element Iron — fusing iron absorbs energy rather than releasing it

How quickly does the late fusion stage of silicon burning proceed in a massive star?

Silicon burning takes about 1 billion years — it is the longest stage Silicon burning takes about 1 million years Silicon burning takes only about 1 day before all the silicon is converted to iron Silicon burning takes about 10,000 years — half as long as carbon burning

What triggers the catastrophic collapse of a massive star's core?

A nearby supernova sends a shockwave that compresses the star The iron core grows until it exceeds the Chandrasekhar limit of about 1.4 solar masses, at which point electron degeneracy pressure fails The star rotates so fast that it tears itself apart Helium flash in the outer layers creates a pressure wave that crushes the core

What happens when the collapsing core of a massive star bounces?

The core stops collapsing and settles into a stable state as a normal star The core evaporates and the star cools down quietly The rebound drives a powerful shockwave through the star's outer layers, blasting them into space as a supernova The core bounces and then collapses again repeatedly for millions of years

How much energy does a core-collapse supernova release, and how does it compare to the Sun?

A supernova releases about the same energy as the Sun produces in a year A supernova releases more energy in seconds than the Sun will emit in its entire 10-billion-year lifetime A supernova releases about 1,000 times the Sun's annual energy output A supernova releases less energy than the Sun because it happens so quickly

What two compact objects can result from the collapsed core of a supernova?

A white dwarf or a brown dwarf A neutron star or a black hole, depending on the mass of the collapsed core An open star cluster or a globular cluster A planetary nebula or a supernova remnant

How bright can a supernova become at its peak?

It is about as bright as a full Moon as seen from Earth It can briefly outshine an entire galaxy of roughly 10 billion stars It reaches the brightness of the Sun on the day of the explosion It is actually dim — most of the energy is invisible to telescopes

What name is given to the type of supernova that results from the collapse of a massive star's iron core?

Type Ia supernova Type II (core-collapse) supernova A nova — a smaller explosion on the surface of a white dwarf A gamma-ray burst — the name for all supernova explosions

What is the onion-shell structure of a massive star just before it explodes?

A hydrogen core surrounded by shells of helium, then iron on the outside A uniform mixture of all elements, well mixed by convection An iron core surrounded by shells of progressively lighter elements — silicon, oxygen, neon, carbon, helium, and hydrogen from center outward A carbon core surrounded only by a thin layer of hydrogen