Hot debris dust around HD 106797

TL;DR

This study detects and characterizes hot debris dust around star HD 106797, revealing a bright, transient debris disk with crystalline silicates, challenging steady-state evolution models.

Contribution

First detection of hot debris dust around HD 106797, with detailed spectral analysis indicating transient events and crystalline silicates in the disk.

Findings

Debris dust temperature ~190 K

Inner disk radius ~14 AU

Disk luminosity 1000 times zodiacal cloud

Abstract

Photometry of the A0 V main-sequence star HD 106797 with AKARI and Gemini/T-ReCS is used to detect excess emission over the expected stellar photospheric emission between 10 and 20 micron, which is best attributed to hot circumstellar debris dust surrounding the star. The temperature of the debris dust is derived as Td ~ 190 K by assuming that the excess emission is approximated by a single temperature blackbody. The derived temperature suggests that the inner radius of the debris disk is ~ 14 AU. The fractional luminosity of the debris disk is 1000 times brighter than that of our own zodiacal cloud. The existence of such a large amount of hot dust around HD 106797 cannot be accounted for by a simple model of the steady state evolution of a debris disk due to collisions, and it is likely that transient events play a significant role. Our data also show a narrow spectral feature between 11 and 12 micron attributable to crystalline silicates, suggesting that dust heating has occurred during the formation and evolution of the debris disk of HD 106797.