AAS 198th Meeting, June 2001
Session 14. Old Stars and the Material Around Them
Display, Monday, June 4, 2001, 9:20am-6:30pm, Exhibit Hall

## [14.02] A Possible Massive Asteroid Belt Around HR 1998

C.H. Chen, M. Jura (UCLA)

We have used the Keck I telescope to image at 11.7 \mum and 17.9 \mum the dust emission around HR 1998, a main sequence A-type star at 21.5 pc from the Sun with an infrared excess detected with IRAS. Even with a 0.57\arcsec FWHM point spread function, the excess is unresolved; we find a dust distance from the star of {\leq} 6.1 AU suggesting that the dust may be contained within a massive asteroid belt. We infer a color temperature of Tdust = 350 K for the grains, consistent with black bodies at 2.9 AU from the star. If the dust grains surrounding HR 1998 have a similar size distribution as the asteroid belt, the total mass of dust around this object is estimated to be 2.3\times1027 g or approximately a thousand times that contained within the main asteroid belt. Since HR 1998 has an estimated age between 100-400 Myr, it seems to possess a relatively young asteroid belt.

The author(s) of this abstract have provided an email address for comments about the abstract: cchen@astro.ucla.edu