Publications
of the
MPIfR Optical & Infrared Interferometry Group

Left: Speckle image of the close binary star Theta 1 C Ori. Right: Relative motion of the componets ot the massive Trapezium star Theta 1 C Ori. The position of the primary is marked by a big asterisk, the solid symbols represent the observed positions of the companion over time The blue line shows a part of a circle around the primary position.

Dieter Schertl, Yuri Y. Balega, Thomas Preibisch, Gerd Weigelt

Orbital motion of the massive multiple stars in the Orion Trapezium

Astronomy and Astrophysics, 402, 267 (2003)

Abstract.
We present bispectrum speckle interferometry of the multiple Orion Trapezium stars theta^1 Ori A, B, and C obtained with the SAO 6m telescope in Russia over a period of 5.5 years (epochs 1995 - 2001). Our diffraction-limited images have a resolution lambda/D of 42 mas (J-band), 57 mas (H-band) and 76 mas (K-band). We clearly detect motion of the companions relative to their primary stars in the systems theta^1 Ori A1-2 (mean separation rho ~ 220 mas, change in position angle Delta P.A. = 6degr), theta^1 Ori B2-3 (rho ~ 205 mas, Delta P.A. = 8degr), and theta^1 Ori C1-2 (rho ~ 37 mas, Delta P.A. = 18degr). In our K-band image of theta^1 Ori B we resolve a fourth visual component, confirming its discovery by Simon et al.~(1999). We determine the J, H, and K magnitudes of the system components and estimate the stellar masses of the companions in the HR-diagram. The companions theta^1 Ori C2 and theta^1 Ori B2 show clear evidence of near-infrared excess in the color-color diagram. The companions theta^1 Ori A2 and theta^1 Ori B3 show much stronger extinction than their primary stars, providing evidence of the presence of circumstellar material around the companions.

You can get this publication ...

preib@mpifr-bonn.mpg.de.
Last modified on 4-March-2003. 		Back to Group Home Page