Measurement of the Surface Gravity of $η$ Boo

van Belle, Gerard T.; Ciardi, David R.; Boden, Andrew F.

Measurement of the Surface Gravity of $η$ Boo

Authors

van Belle, Gerard T.

Ciardi, David R.

Boden, Andrew F.

Description

Direct angular size measurements of the G0IV subgiant $η$ Boo from the Palomar Testbed Interferometer are presented, with limb-darkened angular size of $θ_{LD}= 2.1894^{+0.0055}_{-0.0140} $ mas, which indicate a linear radius of $R=2.672 \pm 0.028 R_\odot$. A bolometric flux estimate of $F_{BOL} = 22.1 \pm 0.28\times 10^{-7}$ erg cm$^{-2}$s$^{-1}$ is computed, which indicates an effective temperature of $T_{EFF}=6100 \pm 28$ K and luminosity of $L = 8.89 \pm 0.16 L_\odot$ for this object. Similar data are established for a check star, HD 121860. The $η$ Boo results are compared to, and confirm, similar parameters established by the {\it MOST} asteroseismology satellite. In conjunction with the mass estimate from the {\it MOST} investigation, a surface gravity of $\log g=3.817 \pm 0.016$ [cm s$^{-2}$] is established for $η$ Boo.
To appear in March 1, 2007 ApJ v657 n1