At an astronomical conference, an astronomer gives a report on a star that has recently begun to interest astronomers because of hints that it may have a planet around it. In his report the astronomer gives the average speed with which this star is moving away from the Sun. How did the astronomer measure this speed?
By looking at the Doppler shift in the lines of the star's spectrum. T/F

True

Explanation:

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Doppler spectroscopy is a measurement system used to estimate the radial velocity of a star.

To make this measurement, a series of observations are made on the spectrum of light emitted by a star. Then, it is detected if the characteristic wavelengths of the light spectrum vary, which may indicate that the radial velocity of the star varies. This situation can be caused by the presence of planets in the orbit of that star.

If a planet is found, it can determine its mass by studying the combinations in the radial velocity of the star.

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