フリードリヒ・ヴィルヘルム・ベッセル
In 1855, William Stephen Jacob of the Madras Observatory claimed that the orbit of the binary showed an anomaly, and it was "highly probable" that there was a "planetary body in connection with this system". This is the first known attempt to use astrometric methods to detect an exoplanet, although Friedrich Bessel had applied similar methods 10 years earlier to deduce the existence of Sirius B.