Dynamical structure of the multiple stellar system HD164492

J.F. GONZÁLEZ; M. E. VERAMENDI

La Plata

Congreso; 58 Reunión Anual de la Asociación Argentina de Astronomía; 2015

Facultad de Ciencias Astronómicas y Geofísicas - UNLP

HD 164492 is a Trapezium-like stellar system with one O-type and several early B-type components immersed in an active star forming region (M20). The relevance of this system has increased after the recent discovery that one of its visual components, HD 164492C, is a spectroscopic triple with a remarkable magnetic field. As a complement of those spectro-polarimetric studies, we present here a survey of the stellar components in the region using available Hubble Space Telescope images. By applying aperture and point spread function (PSF) photometry, we measure accurate separations of close visual pairs and detect new visual companions. Combining these results with previous spectroscopic and photometric studies, we estimate physical separations for 20 probable members of this high-order multiple system. The most interesting feature is that even though it has a global Trapezium-like structure, some of its components are stable binary subsystems organized hierarchically.