The Angular Diameter of λ Boötis
Abstract
Using the CHARA Array and the Palomar Testbed Interferometer, the chemically peculiar star λ Boötis has been spatially resolved. We have measured the limb darkened angular diameter to be θ_{LD}=0.533+/0.029 mas, corresponding to a linear radius of R_{*}=1.70+/0.10 R_{solar}. The measured angular diameter yields an effective temperature for λ Boo of T_{eff}=8887+/242 K. Based on literature surface gravity estimates spanning logg=4.04.2 cm s^{2}, we have derived a stellar mass range of M_{*}=1.11.7 M_{solar}. For a given surface gravity, the linear radius uncertainty contributes approximately σ(M_{*})=0.10.2 M_{solar} to the total mass uncertainty. The uncertainty in the mass (i.e., the range of derived masses) is primarily a result of the uncertainty in the surface gravity. The upper bound of our derived mass range (logg=4.2, M_{*}=1.7+/0.2 M_{solar}) is consistent with 100300 Myr solar metallicity evolutionary models. The midrange of our derived masses (logg=4.1, M_{*}=1.3+/0.2 M_{solar}) is consistent with 23 Gyr metalpoor evolutionary models. A more definitive surface gravity determination is required to determine a more precise mass for λ Boo.
 Publication:

The Astrophysical Journal
 Pub Date:
 April 2007
 DOI:
 10.1086/512077
 arXiv:
 arXiv:astroph/0612723
 Bibcode:
 2007ApJ...659.1623C
 Keywords:

 Stars: Circumstellar Matter;
 Infrared: Stars;
 Stars: Fundamental Parameters;
 stars: individual (λ Boötis);
 Techniques: Interferometric;
 Astrophysics
 EPrint:
 Accepted for publication in The Astrophysical Journal