Copious amounts of hot and cold dust orbiting the main sequence A-type stars HD 131488 and HD 121191

Abstract

We report two new dramatically dusty main sequence stars: HD 131488 (A1 V) and HD 121191 (A8 V). HD 131488 is found to have substantial amounts of dust in its terrestrial planet zone (L IR/L bol ≈ 4 × 10-3), cooler dust farther out in its planetary system, and an unusual mid-infrared spectral feature. HD 121191 shows terrestrial planet zone dust (L IR/Lbol ≈ 2.3 × 10-3), hints of cooler dust, and shares the unusual mid-infrared spectral shape identified in HD 131488. These two stars belong to sub-groups of the Scorpius-Centaurus OB association and have ages of ∼10 Myr. HD 131488 and HD 121191 are the dustiest main sequence A-type stars currently known. Early-type stars that host substantial inner planetary system dust are thus far found only within the age range of 5-20 Myr. © 2013. The American Astronomical Society. All rights reserved.