A trial question (1 Viewer)

[Sam14113]

This question comes from a past CSSA trial paper. The answer provided is C. I have no idea why that would be the answer, and no solutions are provided for the multiple choice questions. Can someone please explain?

 

[Mikdin11]

Thicker spectral lines = denser star.

Masses of giants and supergiants may be 10 to 30 times that of the Sun (main sequence star), but their volumes are often 1,000,000 to 10,000,000 times greater. Thus they are low density stars.

So the thicker spectral lines must be the main sequence star because it is denser, and the thinner spectral lines must be the red supergiant because it is less dense.

 

[Sam14113]

Ahh okay, thank you

Would you not expect the actual chemical composition of the stars to be different? Like presumably a main sequence star still has hydrogen while a red supergiant does not, so you'd expect the lines to not just change in thickness but in position as well? What have I misunderstood here?

Thanks again

 

[Mikdin11]

Ahh okay, thank you

Would you not expect the actual chemical composition of the stars to be different? Like presumably a main sequence star still has hydrogen while a red supergiant does not, so you'd expect the lines to not just change in thickness but in position as well? What have I misunderstood here?

Thanks again

Yeah I'd agree. I think they r just trying to test whether people know that thicker spectral lines = more dense star, so have ignored the shift in spectral lines.