The Chara Array Angular Diameter of HR 8799 Favors Planetary Masses for Its Imaged Companions
Abstract
HR8799 is an hF0 mA5 gamma Doradus-, lambda; Bootis-,Vega-type star best known for hosting four directly imaged candidate planetary companions. Using the CHARA Array interferometer, we measure HR 8799's limb-darkened angular diameter to be 0.342 +/- 0.008 mas (an error of only 2%). By combining our measurement with the star's parallax and photometry from the literature, we greatly improve upon previous estimates of its fundamental parameters including stellar radius (1.44 +/- 0.06 R ), effective temperature (7193 +/- 87 K, consistent with F0), luminosity (5.05 +/-0.29 L ), and the extent of the habitable zone (HZ; 1.62-3.32 AU). These improved stellar properties permit much more precise comparisons with stellar evolutionary models, from which a mass and age can be determined once the metallicity of the star is known. Considering the observational properties of other lambda Bootis stars and the indirect evidence for youth of HR 8799, we argue that the internal abundance, and what we refer to as the effective abundance, is most likely near solar.
Document Details
- Document Type
- Technical Report
- Publication Date
- Dec 10, 2012
- Accession Number
- ADA581166
Entities
People
- Daniel Huber
- Ellyn K. Baines
- Harold A. . Mcalister
- Jeremy Jones
- Judit Sturmann
- Laszlo Sturmann
- Nils H. Turner
- Russel J. White
- Tabetha Boyajian
- Theo A. Ten Brummelaar
Organizations
- United States Naval Research Laboratory