Multiplicity among F-type stars

Abstract

As part of a homogeneous all-sky volume-complete sample of half a thousand solar-type stars within 25pc we present a census for the subset of the 150 - mostly F-type stars - in the mass range 1.1 M ≤ M ≤ 1.7 M in terms of their observed multiplicities. The major obstacle, as expected, arises from the onset of stellar rotation in this mass range for it continues to support many hidden companions. Yet, a solid increase of the fraction of binary and higher level systems as a function of the primary mass is manifest. There is even the prospect that on account of many companion candidates the single-star fraction may already converge to zero at the transition to the A-type stars. © 2012. The American Astronomical Society. All rights reserved..