Hong Wu, Chao-Jian Wu, Chen Cao, Sebastian Wolf, Jing-Yao Hu
We present the optical to mid-infrared SEDs of 11 debris disk candidates from
$Spitzer$ SWIRE fields. All these candidates are selected from SWIRE 24$\mu$m
sources matched with both the SDSS star catalog and the 2MASS point source
catalog. They show an excess in the mid-infrared at 24$\mu$m
($K_S$-[24]$_{Vega}$ $\ge$ 0.44) indicating the presence of a circumstellar
dust disk. The observed optical spectra show that they are all late type
main-sequence stars covering the spectral types of FGKM. Their fractional
luminosities are well above 5$\times10^{-5}$, even up to the high fractional
luminosity of 1$\times10^{-3}$. The high galactic latitudes of SWIRE fields
indicate that most of these candidates could belong to the oldest stars in the
thick disk. Our results indicate that the high fractional luminosity debris
disks could exist in the old solar-like star systems, though they are now still
quite rare. Their discoveries at high-galactic latitudes will also provide us
an excellent opportunity to the further studies of properties and evolution of
the debris disk in the ISM poor environments.
View original:
http://arxiv.org/abs/1202.1323
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