Peter van de Kamp

Van de Kamp was the son of Lubbertus van de Kamp and Engelina C. A. van der Wal. His younger brother Jacob van de Kamp was also a successful scientist: an organic chemist, who spent most of his career in the United States. Van de Kamp studied at the University of Utrecht and started his professional career at the Kapteyn Astronomical Institute in Groningen working with Pieter Johannes van Rhijn. In 1923 he left for the Leander McCormick Observatory at the University of Virginia for a year's residence supported by the Draper Fund of the National Academy of Sciences. There he assisted Samuel Alfred Mitchell with his stellar parallax program and Harold Alden with the Boss star project, both concerned with the proper motion and apparent position of stars relative to our solar system. The following year Van de Kamp went to the Lick Observatory in California as a Kellogg fellow. There he received his PhD from the University of California in Astronomy in June 1925. The next year he also received a PhD from the University of Groningen. Van de Kamp returned to McCormick on October 1, 1925, to take up the position left vacant by Harold Alden, who had just taken up the directorship of the Yale University Observatory Southern Station in Johannesburg, South Africa. In the spring of 1937, Van de Kamp left McCormick Observatory to take over as director of Swarthmore College's Sproul Observatory. One of his early pupils in astrometry was Nancy Grace Roman, who went on to become NASA's first Chief of Astronomy. ==Barnard's Star affair==

While at Sproul Observatory, he made astrometric measurements of Barnard's Star and in the 1960s reported a periodic "wobble" in its motion, apparently due to planetary companions. It was not until several decades had passed that a consensus had formed that this had been a spurious detection. In 1973 astronomers George Gatewood of the Allegheny Observatory and Heinrich Eichhorn of the University of Florida, using data obtained with improved equipment on the 30-inch Thaw Refractor telescope, did not detect any planets but instead detected a change in the color-dependent image scale of the images obtained from the 24-inch refractor telescope at the Sproul Observatory used by Van de Kamp in his study. Astronomer John L. Hershey found that this anomaly apparently occurred after each time the objective lens was removed, cleaned, and replaced. Hundreds more stars showed "wobbles" like Barnard's Star's when photographs before and after cleaning were compared – a virtual impossibility. while modern radial velocity curves place a limit on the planets much smaller than claimed by Van de Kamp. A study in 2018 suggested that there was a planet orbiting Barnard's Star (Barnard's Star b), albeit of much lower mass than Van de Kamp could have detected; Additionally, three other candidate low-mass planets were proposed in this study. All of these planets orbit closer to the star than the habitable zone. However, the indicated masses of the planets are again far below those capable of detection by Van de Kamp. ==Other work==

Van de Kamp's career at Sproul included hours spent on astrometry and advanced telescopic techniques. He published frequently in the Bulletin of the American Astronomical Society and elsewhere. From the 1940s on, Van de Kamp and his staff made similar claims of planetary systems around the nearby stars Lalande 21185, 61 Cygni, and many others, based on the same flawed photographic plates. All of these claims have been refuted. In 2021, even this planet's existence was questioned. Debate over the existence of a stellar or planetary companion is ongoing within the literature. ==Later life==

In 1972, he retired from Swarthmore and returned to the Netherlands, where he became Fulbright Professor at the University of Amsterdam. Van de Kamp returned to his native Holland at the end of his life and died in suburban Amsterdam on May 18, 1995, at the age of 93. He helped to organize an orchestra in Charlottesville, which he conducted and included fellow astronomer Alexander Vyssotsky. He also composed music for orchestra as well as for piano. From 1944 to 1954 he was conductor of the Swarthmore College Symphony Orchestra. He combined his musical gifts with another hobby, movies, by playing silent films on Swarthmore campus and accompanying them on the piano. In 1982, he was awarded the Prix Jules Janssen by the Société Astronomique de France. ==See also==