Adaptive Optics Observations of Arcturus using the Mount Wilson 100 Inch Telescope

Abstract

Upon inspection of the multiple-star results in the Hipparcos catalog, the flag for entry number 69673 particularly stands out; it is Arcturus, for which no companion has been reported previously. The Hipparcos companion is reported to be at a separation of 0.255"+/-0.039" with a magnitude difference in a broadband filter (peaked near 460 nm) of 3.33+/-0.31. We present recent results using the natural guide star adaptive optics system on the Mount Wilson 100 inch telescope showing Arcturus to be a single star.