The life-span of every star is related to mass, which determines luminosity (brightness). The table shows the masses, lifetimes, and luminosities of two stars compared to that of the Sun.

Question

How does the Sun's lifetime compare to other main sequence stars? Move each lifetime into the table next to the star it describes.
Star
Mass (Mo)
Main Sequence Lifetime (years)
Luminosity (Lo)
Proxima Centauri
0.12
0.0017
Spica
2,200
Sun
11
1
1
107
1010
1012

Answer 1

To compare the Sun's lifetime with those of other main sequence stars based on the given masses (Mo), here is how we can place the main sequence lifetimes into the appropriate slots in the table.

From the context:

• Proxima Centauri (Mass: 0.12 Mo): A low-mass star. Its lifetime would be considerably longer than the Sun's due to the mass-luminosity relationship, typically reaching trillions of years.

• Spica (Mass: 2,200 Mo): A high-mass star. Its lifetime is much shorter due to its high luminosity and increased rate of nuclear fusion.

• Sun (Mass: 1 Mo): The reference star with a main sequence lifetime of about 11 billion years.

Given the information, let’s fill in the lifetimes in years (using scientific notation for clarity):

| Star | Mass (Mo) | Main Sequence Lifetime (years) | Luminosity (Lo) | |------------------|-----------|---------------------------------|------------------| | Proxima Centauri | 0.12 | 10^12 (trillion years) | 0.0017 | | Sun | 1 | 10^11 (11 billion years) | 1 | | Spica | 2,200 | 10^7 (about 10 million years) | > 10,000 |

In summary:

• Proxima Centauri has a significantly longer lifetime (∼1 trillion years).
• The Sun's lifetime is about 11 billion years.
• Spica has a much shorter lifetime (∼10 million years).

This demonstrates how massive stars have shorter life spans in comparison to lower mass stars.