Cool Stars 14 - Submitted Abstract # 288
This version created on 05 October 2006

A Search for Warm Dust in the Habitable Zones Around Solar-Type Stars


Samantha Lawler, MSC/Caltech
David Ciardi, MSC/Caltech
Charles Beichman, MSC/Caltech
Angelle Tanner, JPL/Caltech
Geoff Bryden, JPL
Karl Stapelfeldt, JPL
David Harkner, UCSD
Rachel Akeson, MSC/Caltech

As part of a program to search for and characterize the presence of
warm dust in the habitable zones around nearby solar like stars, we
have observed 146 FGKM stars with the Spitzer short-low and long-low
IRS modules, and present our preliminary survey findings.  The IRS
observations are capable of detecting excesses as small as 2% of the
photosphere within the range of IRS wavelengths, 7 through 34 um.  Out
of the 146 stars observed, 15 show significant excess emission
longward of 25 um.  Out of these 15 detections, one star (HD 10647)
has a known planet, and 3 of the 15 stars with IRS excesses are
younger than 2 Gyr.  Eight stars with IRS excess also have MIPS 70  um
excesses (from either the FGK or SIM/TPF surveys).  Additionally,
eight stars out of the entire sample of 146 stars have MIPS 70
excesses but have no IRS excess.  On average, the stars' metallicities
are lower than solar, with only 5 stars having metallicities greater
than solar.  The observed dust luminosities for these 15 stars range
from Ldust/L* ~ 1e-5 to 1e-4.

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