Optical interferometric observations of Theta 1 Orionis C from NPOI and implications for the system orbit

摘要

With the Navy Prototype Optical Interferometer (NPOI), the binary systemTheta 1 Orionis C, the most massive member of the Trapezium, was spatiallyresolved over a time period extending from February 2006 to March 2007. Thedata show significant orbital motion over the 14 months, and, after combiningthe NPOI data with previous measurements of the system from the literature, theobservations span 10 years of the orbit. Our results indicate that thesecondary did not experience an unusually close periastron passage this year,in contradiction to the prediction of a recently published, highly eccentric~11 year orbit. Future observations of this source will be required to improvethe orbital solution. Possible implications of the results in terms of systemdistance are discussed, although a main conclusion of this work is that adefinitive orbit solution will require more time to obtain sufficient phasecoverage, and that the interaction effects expected at periastron did not occurin 2007.