Paper: astro-ph/0510294
Date: Tue, 11 Oct 2005 18:15:04 GMT (209kb)

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

Authors: D. C. Hines, D. E. Backman, J. Bouwman, L. A. Hillenbrand, J. M.
Carpenter, M. R. Meyer, J. S. Kim, M. D. Silverstone, J. Rodmann, S. Wolf, E.
E. Mamajek, T. Y. Brooke, D. L. Padgett, T. Henning, A. Moro-Martin, E.
Stobie, K. D. Gordon, J.E. Morrison, J. Muzerolle, K.Y.L. Su

Comments: 31 pages, 6 figures (poor quality bitmaps, but readable), accepted
for publication in The Astrophysical Journal
\\
We report the discovery of a debris system associated with the $\sim 30$ Myr
old G3/5V star HD 12039 using {\it Spitzer Space Telescope} observations from
3.6 -- 160$\mu$m. An observed infrared excess (L$_{\rm IR}$/L$_{\ast} =
1\times10^{-4}$) above the expected photosphere for $\lambda \gtrsim 14\mu$m is
fit by thermally emitting material with a color temperature of T$\sim 110$ K,
warmer than the majority of debris disks identified to date around Sun-like
stars. The object is not detected at 70$\mu$m 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 $\gtrsim 7 \mu$m that reside in a belt orbiting the star at 4--6
AU. An alternate model dominated by smaller grains, near the blow-out size
$a\sim 0.5\mu$m, 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 $\sim$ few $\times 10^{2}$yrs.

\\ ( http://arXiv.org/abs/astro-ph/0510294 , 209kb)