Program: GN-2008B-Q-95

Title:Binaries among the Most Massive Stars
PI:Douglas R Gies
Co-I(s): Saida Caballero-Nieves

Abstract

We propose to continue a high angular resolution survey of the most massive stars in the nearby complex Cyg OB2. We will use Gemini-N ALTAIR/NIRI observations to search for astrometric companions in the separation range of 0.06 - 10 arcsec with a magnitude difference less than 10 mag. The observations will test the idea that the formation of very massive stars involves binary stars that are formed through disk fragmentation or capture. Discovery of companions in this relatively nearby cluster (where we can angularly resolve close binaries) will provide guidance in the interpretation of apparently supermassive stars in distant locations. The large dynamic range of the observations will reveal any low mass companions that are present. This survey combined with published spectroscopic results will establish the binary frequency of massive stars in a very young cluster environment. The survey will also be important for verification of fundamental parameters derived from spectroscopy, adjustments to main sequence fitting and distance estimates, identification of colliding wind binaries, and discovery of binaries amenable to future mass determinations. The massive star environment in Cyg OB2 may be similar to that of the earliest epoch of star formation, so that a study of the role of binaries there will help us understand the formation of the first stars in the Universe.

Publications using this program's data