Astrophysics, abstract
astro-ph/0609555

From: Joseph Rhee [view email]

Date: Tue, 19 Sep 2006 21:41:45 GMT (455kb)

Characterization of Dusty Debris Disks: the IRAS and Hipparcos Catalogs

Authors: Joseph H. Rhee, Inseok Song, B. Zuckerman, Michael McElwain

Comments: Accepted to ApJ

Dusty debris disks around main sequence stars are signposts for the existence of planetesimals and exoplanets. From cross-correlating Hipparcos stars with the IRAS catalogs, we identify 153 stars within 120 pc of Earth that show excess emission at 60 $\micron$. This search took special precautions to avoid false positives. Our sample is reasonably well distributed from late B to early K type stars, but it contains very few later type stars. Even though IRAS flew more than 20 years ago and many astronomers have cross correlated its catalogs with stellar catalogs, we were still able to newly identify debris disks at 37 main sequence stars; of these, 35 are within 100 pc of Earth. The power of an all-sky survey satellite like IRAS is evident when comparing our 37 new debris disks with the total of only 22 dusty debris disk stars first detected with the more sensitive, but pointed, satellite ISO. Our findings indicate: (1) as one progresses from stellar ages of $\sim$10 Myr to a few Gyr, a smaller percentage of stars display fractional infrared luminosities $\tau$ (= $L_{IR}/L_{bol}$) above the IRAS threshold which is about $10^{-5}$. (2) Peak $\tau$ is a few times $10^{-3}$ at all ages later than $\sim$10 Myr; this might be because occasional catastrophic dust-generating events can occur at any age. (3) The spread of measured $\tau$ at ages $\sim$10 Myr is about a factor of 10, increasing to about 100 at later ages; given the measured peak $\tau$ (item 2) and IRAS threshold (item 1), the measured spread of $\tau$ cannot be greater than 100. (4) At any given age late-type stars tend to have the largest taus. Please download the paper for the rest of the abstract (items 5-13) and more.

http://arxiv.org/abs/astro-ph/0609555