Copious Amounts of Hot and Cold Dust Orbiting the Main Sequence A-type Stars HD 131488 and HD 121191

TL;DR

This paper reports the discovery of two young, dusty A-type main sequence stars with substantial inner planetary system dust, highlighting their uniqueness and potential for studying early planetary system evolution.

Contribution

It presents the identification and characterization of two extremely dusty A-type stars, revealing their unusual mid-infrared features and their significance in understanding early planetary system development.

Findings

HD 131488 and HD 121191 are the dustiest known main sequence A-type stars.

Both stars exhibit substantial terrestrial planet zone dust within ~10 Myr age.

Unusual mid-infrared spectral features suggest unique dust compositions or structures.

Abstract

We report two new dramatically dusty main sequence stars: HD 131488 (A1V) and HD 121191 (A8V). HD 131488 is found to have substantial amounts of dust in its terrestrial planet zone (L_IR/L_bol~4x10^-3), cooler dust further out in its planetary system, and an unusual mid-infrared spectral feature. HD 121191 shows terrestrial planet zone dust (L_IR/L_bol~2.3x10^-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.