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Flashcards in Stars Deck (2)
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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.