Question

Your research team analysis the light of a mysterious object in space. By using a spectrometer,
you can observe the following spectrum of the object. The Hα line peak is clearly visible:
(a) Mark the first four spectral lines of hydrogen (Hα, Hβ, Hγ, Hδ) in the spectrum.
(b) Determine the radial velocity and the direction of the object’s movement.
(c) Calculate the distance to the observed object.
(d) What possible type of object is your team observing?
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Answer 1

Analysis of light of a mysterious object in space

Explanation:

• Please refer to the attached picture for the four spectral lines.

• The radial velocity and the direction of the object’s movement:

v = zc = (3 * 10^5) (800/ 656.28 - 1) = 65700 km/s

Velocity is positive and wavelength is elongated. So the object is moving away from us.

• Applying Hubble's law, distance D = v/ Ho = 65700 / 72 = 913 MPc

• Type of object: Galaxy.