Proper motions in Cepheus A

Abstract

We present an analysis of radio continuum observations made with the Very Large Array toward the region of massive star formation Cepheus A. The main purpose of this analysis is to search and study proper motions in the radio sources over the two decades of time covered by the observations. The four components of source W, located in Cep A West, clearly show westward proper motions in the range of 120 to 280 km s(-1). We believe that these components are being excited by the thermal jet Cep A HW3d, located to their east. Furthermore, we propose that after being deflected at the position of source W, the Cep A HW3d jet moves towards the NW and produces the optical source GGD 37. The source Cep A HW7 shows a complex pattern of proper motions for which we discuss several possible explanations.