In searches for planets orbiting stars other than the Sun, what is the astrometric method?
A) searching for tiny "bumps" on images of a star, due to the light from a planet located close to the star
B) searching for tiny displacements of the infrared image of a star compared with its optical image, caused by the presence of planets that are cool and emit primarily in the infrared
C) searching for tiny wobbles in the position of a star, due to the gravitational pull of a planet orbiting around it
D) searching for tiny wobbles in the positions of absorption lines in a star's spectrum, caused by radial velocity variations of the star as the result of a planet orbiting around it

Question

Quizplus · Accepted Answer

The astrometric method involves searching for tiny wobbles in the position of a star, which are caused by the gravitational pull of a planet orbiting around it. This method relies on the fact that a planet and its host star orbit around their common center of mass, causing the star to move in a small orbit that can be detected through precise measurements of its position in the sky.

In Searches for Planets Orbiting Stars Other Than the Sun