Question

The spectrum of the Sun has hundreds of strong lines of nonionized iron but only a few, very weak lines of helium. A star of spectral type B has very strong lines of helium but very weak iron lines. Do these differences mean that the Sun contains more iron and less helium than the B star? Explain.

Answer 1

The spectral lines of nonionized iron in the Sun and helium in a B type star indicate differences in atmospheric temperatures rather than composition. Strong spectral lines reflect the temperature and conditions at which elements are ionized, not just the abundance of those elements in the star.

Step-by-step explanation:

The differences in spectral lines between the Sun and a B type star do not necessarily indicate which star contains more iron or helium. The strength of spectral lines in a star's spectrum is dependent on the temperature and physical conditions of the star's atmosphere, not just its composition. For instance, the very strong lines of nonionized iron in the Sun's spectrum suggest that it has a cooler atmosphere where iron is not ionized. Conversely, a B type star has a hotter atmosphere, which is why it displays very strong lines of helium but very weak iron lines. Even though helium is present in both stars, its spectral lines are more prominent in hotter stars due to the difference in atmospheric temperature influencing the ionization levels of various elements.