| Pierre Renson's first astrophysical interest and most important contributions are related to the magnetic stars, including notably an ARA&A review with Paul Ledoux on the subject in 1966. Pierre Renson later developed an original method for the determination of periods in astrophysical time series well suited to the observations of the Ap variables. He applied this method to many existing data sets and to observations specifically collected at ESO La Silla. With F. Catalano he compiled in 1984 a catalogue of the periods of Ap stars. Several other catalogues, and supplements followed, viz. a catalogue of Ap and Am stars in open clusters (1988), a catalogue of lambda Bootis candidates (1990, with C.Boehm and R. Faraggiana) and a general catalogue of Ap and Am stars (1991, with M. Gerbaldi and F. Catalano and most recently, in 2009 with J. Manfroid). His attention to details led him to publish e.g. a corrigenda to the Bright star catalogue and various papers on stellar designations and catalogues. Pierre Renson remained an active researcher well beyond his official retirement from Liège University in 1988. In recent years, his attention was mostly focusing on some mathematical problems. In 2017, he published a book on the fascinating world of numbers and a few weeks before his demise he was still working on another book on vectors. |