AAS 207th Meeting, 8-12 January 2006
Session 63 From Here to Eternity: The Spitzer Legacy Programs
Poster, Tuesday, 9:20am-6:30pm, January 10, 2006, Exhibit Hall

## [63.48] The Formation and Evolution of Planetary Systems (FEPS): Discovery of an Unusual Debris System Associated with HD 12039

E. E. Mamajek (CfA), D. C. Hines (Space Science Institute), D. E. Backman (NASA Ames), J. Bouwman (MPIA), L. A. Hillenbrand, J. M. Carpenter (Caltech), M. R. Meyer, J. S. Kim, M. D. Silverstone (Steward Observatory, UofA), J. Rodmann, S. Wolf (MPIA), T. Y. Brooke (Caltech), D. L. Padgett (SSC), Th. Henning (MPIA), A. Moro-Martin (Princeton), E. Stobie, K. D. Gordon, J. Morrison, J. Muzerolle, K. Su (Steward Observatory, UofA)

We report the discovery of a debris system associated with the ~30 Myr old G3/5V star HD~12039 using Spitzer Space Telescope observations from 3.6 -- 160\mum. An observed infrared excess (L\rm IR/L\ast = 1\times10-4) above the expected photosphere for \lambda \gtrsim 14\mum is fit by thermally emitting material with a color temperature of T~110 K, warmer than the majority of debris disks identified to date around Sun-like stars. The object is not detected at 70\mum with a 3\sigma upper limit 6 times the expected photospheric flux. The spectrum of the infrared excess can be explained by warm, optically thin material comprised of blackbody-like grains of size \gtrsim 7 \mum that reside in a belt orbiting the star at 4--6 AU. An alternate model dominated by smaller grains, near the blow-out size a~0.5\mum, located at 30-40AU is also possible, but requires the dust to have been produced recently since such small grains will be expelled from the system by radiation pressure in ~ few \times 102yrs.

This work is based in part on observations made with the Spitzer Space Telescope, which is operated by the Jet Propulsion Laboratory, California Institute of Technology under NASA contract 1407. FEPS is pleased to acknowledge support through NASA contracts 1224768, 1224634, 1224566 administered through JPL.