An astronomy class is so excited by the discovery of planets around other stars that they decide to do a library exhibit on the subject so that everyone in the school can learn about it. In this exhibit they want to pay tribute to both the astronomers of today who have done the work AND some of the scientists of the past whose work was essential to making the discoveries possible (and directly related to the techniques involved). Which of the following scientists of the past should definitely be included in the exhibit?
George Herbig Ejnar Hertzsprung Ptolemy
Gerard Kuiper Christian Doppler

The Scientist with the most significant contribution to the discovery of planets around other stars is Christian Doppler and his work that made this discovery possible is the Principle of DOPPLER EFFECT

Christian Doppler was an Austrian scientist and physicist whose principle Doppler effect explained how observed frequency of light and sound waves are affected by a relative motion of both the source and detector