The debris disk candidates:eleven 24μm excess stars in the Spitzer SWIRE fields  

作　　者：Hong Wu Chao-Jian Wu Chen Cao Sebastian Wolf Jing-Yao Hu 

机构地区：[1]Key Laboratory of Optical Astronomy, National Astronomical Observatories, Chinese Academy of Sciences, Beijing 100012, China [2]Department of Astronomy, Beijing Normal University, Beijing 100875, China [3]Institute of Space Science and Physics, Shandong University at Weihai, Weihai 264209, China [4]Shandong Provincial Key Laboratory of Optical Astronomy ＆ Solar-Terrestrial Environment, Weihai 264209, China [5]Max Planck Institute for Astronomy, K6nigstuhl 17, 69117 Heidelberg, Germany

出　　处：《Research in Astronomy and Astrophysics》2012年第5期513-528,共16页天文和天体物理学研究（英文版）

基　　金：supported by the National Natural Science Foundation of China (Grant Nos. 11173030, 11078017, 10833006, 10978014 and 10773014);partly supported by the China Ministry of Science and Technology under the State Key Development Program for Basic Research (2007CB815400 and 2012CB821800);S. Wolf was supported by the German Research Foundation (DFG) through the Emmy Noether grant WO 857/2

摘　　要：We present the optical to mid-infrared SEDs of 11 debris disk candidates from Spitzer SWIRE fields. All the candidates are selected from SWIRE 24 μm sources matched with both the SDSS star catalog and the 2MASS point source catalog. They show an excess in the mid-infrared at 24 μm （Ks-[24]vega 〉 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× 10-5, even up to the high fractional luminosity of 1×10-3. 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 high fractional luminosity debris disks could exist in old solar-like star systems, though they are still quite rare. Their discovery at high galactic latitudes also provides an exellent opportunity for further study of the properties and evolution of debris disks in regions of the Galaxy with low densities of ISM, called ISM poor environments.We present the optical to mid-infrared SEDs of 11 debris disk candidates from Spitzer SWIRE fields. All the candidates are selected from SWIRE 24 μm sources matched with both the SDSS star catalog and the 2MASS point source catalog. They show an excess in the mid-infrared at 24 μm （Ks-[24]vega 〉 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× 10-5, even up to the high fractional luminosity of 1×10-3. 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 high fractional luminosity debris disks could exist in old solar-like star systems, though they are still quite rare. Their discovery at high galactic latitudes also provides an exellent opportunity for further study of the properties and evolution of debris disks in regions of the Galaxy with low densities of ISM, called ISM poor environments.

关 键 词：infrared stars -- planetary systems protoplanetary disks - stars for marion 

分 类 号：TN946.1[电子电信—信号与信息处理] TP333.35[电子电信—信息与通信工程]