Photometry and spectroscopy of the central star of the Trifid nebula ^*

¹ Hamburger Sternwarte, Gojenbergsweg 112, D-21029 Hamburg, Germany
² Astronomical Institute, Charles University, V Holešovičkách 2, 180 00 Praha 8, Czech Republic
³ Dr. Remeis-Sternwarte, Astronomisches Institut der Universität Erlangen-Nürnberg, Sternwartstraße 7, D-96049 Bamberg, Germany

Send offprint request to: P. Mayer

Received: 12 December 1997
Accepted: 27 July 1998

Abstract

UBV photometry of the central star of the Trifid nebula - HD 164492, which has so far been suspected of photometric as well as of radial velocity variability - is presented. The results of our photometry do not confirm any variability. Moreover, based on new high resolution CCD spectra any radial velocity variability can be discarded. Photometry of several other members of the multiple stellar system is included; according to this photometry, the system is a physical one. Equivalent widths for the main component of HD 164492 are given. Positions measured on CCD exposures are presented too.