HD 169981 -an overlooked photometric binary?^*

¹ Thüringer Landessternwarte Tautenburg, Karl-Schwarzschild-Observatorium, 07778 Tautenburg, Germany e-mail: lehm@tls-tautenburg.de
² Astrophysikalisches Institut Potsdam, An der Sternwarte 16, 14483 Potsdam, Germany e-mail: ghildebrandt@aip.de
³ Institute of Astronomy, Bulgarian Academy of Sciences, Sofia, Bulgaria e-mail: kpanov@astro.bas.bg

Corresponding author: G. Scholz, gscholz@aip.de

Received: 30 January 2001
Accepted: 2 May 2001

Abstract

In 1999 and 2000 we obtained spectroscopic and photometric observations of the A-type binary star HD 169981. The observations were part of a campaign to search for short-term photometric and radial-velocity variations among early-type binaries. From the radial velocities of 18 metal lines we derived more precise orbital elements. Quite unexpectedly, our photometric data show a dip that could be caused by an eclipse. The same feature is also visible in the Hipparcos data. From our analysis of the available observations we have estimated the physical parameters of the binary. Neither the spectroscopic nor the photometric observations hint at any short-term variations.