Simultaneous uvby photometry of the δ Sct star HD 129231

We present the results of a three-year Strömgren uvby photometric study of the recently discovered multiperiodic low amplitude δ Sct-type pulsator HD 129231. Some additional Hβ-Crawford measurements were also collected. Multiperiodicity is needed to describe the pulsational behaviour of this variable during each of the observing runs. A set of five significant frequencies has been found as the best fitting for the 1997 dataset, but only the two main ones result as significant during the 1995 and 1996 observing runs. Amplitude variations from season to season are also found for the main frequency f1. Nonradial pulsation is suggested for some of the modes. Using the derived uvbyβ indices, the most relevant physical parameters of HD 129231 are also determined placing this object as a hot Population I δ Sct star evolving on its main sequence stage.