We call the first method the Radial Velocity method.
You may think of an orbit as the planet orbiting the star, with the star stationary at the center. This is *almost* the truth, but even though planets are small compared to their stars they “tug” on the star ever so slightly causing it to move around.
This happens in our Solar System too! Jupiter is the biggest culprit - check out this gif (not to scale) of how Jupiter tugs on the Sun.
#SpaceTalkTuesday (5/)
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