Question

What characteristic do all stars on the main sequence share?

They all have the same size.
They all have the same luminosity.
They all have the same temperature.
They are all fusing hydrogen into helium in their cores.
They will all go through a helium flash in the future.

Answer 1

All main sequence stars share the characteristic of fusing hydrogen into helium in their cores, a process that defines their main sequence status and varies in luminosity and temperature based on the star's mass.

Step-by-step explanation:

The characteristic that all stars on the main sequence share is that they are all fusing hydrogen into helium in their cores. This process of hydrogen fusion is what defines a star's presence on the main sequence, and stars spend roughly 90% of their lifetimes in this stage. The main sequence is represented on the Hertzsprung-Russell (H-R) diagram, which plots stars according to their luminosity and surface temperature. Although main sequence stars all fuse hydrogen, they are spread across a spectrum of luminosities and temperatures. The reason for this variation lies in the mass of the stars: more massive main sequence stars are hotter and more luminous, while less massive ones are cooler and dimmer.

Answer 2

Stars on the main sequence share the characteristic of fusing hydrogen into helium in their cores. They differ in properties like luminosity and temperature based on their mass.

Step-by-step explanation:

All stars on the main sequence share the characteristic of fusing hydrogen into helium in their cores. This is what defines a star as being on the main sequence. Stars spend about 90% of their lifetime in this phase, undergoing nuclear fusion and maintaining a state of equilibrium.

While all stars on the main sequence are fusing hydrogen, they differ in other properties such as luminosity and surface temperature. These differences are primarily due to the mass of the star. Massive stars have higher temperatures and luminosities, while low-mass stars have lower temperatures and luminosities.