Stars Flashcards
1
Q
State and explain how stellar parallax is used to measure distances in space.
A
The apparent motion or displacement of a star is relative to the position of more distant stars. This is caused by the Earth’s orbit around the Sun. An angle of parallax of 1 arcsecond when displacement of Earth is 1AU corresponds to distance 1 pc
2
Q
Suggest why hydrogen spectral lines might often be used to measure a star’s velocity.
A
Hydrogen is most common element in stars and has the most intense (spectral) lines. Intensity of light from other elements may be too low for accurate
measurement.
