The absorption spectrum of a certain star is recorded.An absorption line of hydrogen in found at 745nm in the spectrum of the star. In the lab this absorption line is found at 728nm. Is the star moving towards or away from the Earth? Explain how you arrived at this answer. Calculate the radial velocity of the star with respect to the Earth.
TY for your help. We nv covered this in class so I have no idea where to start...
2007-02-14 09:57:18 · 3 answers · asked by Anonymous in Science & Mathematics ➔ Astronomy & Space
The star's spectral line is of a longer wavelength, or shifted towards the red end of the spectrum.
In analogy to observed wavelength in the doppler effect for sound, a longer ("stretched out") wavelength indicates that the object is moving away.
I refer you back to your physics text for the radial velocity.
Also, Doppler Redshift is described here:
http://en.wikipedia.org/wiki/Redshift#Measurement.2C_characterization.2C_and_interpretation
2007-02-14 10:19:37 · answer #1 · answered by Jerry P 6 · 0⤊ 0⤋
Since the absorption line is found at a longer wavelength, it means that the star is moving further away.
2007-02-17 15:32:20 · answer #2 · answered by Tenebra98 3 · 0⤊ 0⤋
I would say it's moving toward because the wavelength is smaller. This is due to the doppler effect.
2007-02-14 18:01:36 · answer #3 · answered by thyplo101 2 · 0⤊ 1⤋