Orbital motion of the massive multiple stars in the Orion Trapezium
1
Max-Planck-Institut für Radioastronomie, Auf dem Hügel 69, 53121 Bonn, Germany
2
Special Astrophysical Observatory, Nizhnij Arkhyz, Zelenchuk region, Karachai-Cherkesia, 357147, Russia
Corresponding author: Th. Preibisch, preib@mpifr-bonn.mpg.de
Received:
12
August
2002
Accepted:
6
February
2003
We present bispectrum speckle interferometry of
the multiple Orion Trapezium stars 
A, B, and C obtained
with the SAO 6 m telescope in Russia over a
period of 5.5 years (epochs 1995–2001).
Our diffraction-limited images have a resolution
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
A1–2 (mean separation 
mas,
change in position angle 
),
B2–3 (
mas, 
), and
C1–2 (
mas, 
).
In our K-band image of B we resolve a fourth visual component,
confirming its discovery by Simon et al. ([CITE]).
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 C2 and B2 show clear evidence of near-infrared
excess in the color-color diagram. The companions A2 and B3 show
much stronger extinction than their primary stars, providing evidence
of the presence of circumstellar material around the companions.
Key words: techniques: interferometric / stars: individual: θ1Ori C, θ1Ori A, θ1Ori B / stars: binaries: general / stars: pre-main sequence
© ESO, 2003