PROTOPLANETARY AND TRANSITIONAL DISKS IN THE OPEN STELLAR CLUSTER IC 2395
PROTOPLANETARY AND TRANSITIONAL DISKS IN THE OPEN STELLAR CLUSTER IC 2395
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DOI：
10.3847/0004-637x/832/1/87
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发表时间：
2016-09
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通讯作者：
Z. Balog;N. Siegler;G. Rieke;László L. Kiss;J. Muzerolle;R. Gutermuth;C. Bell;J. Vinkó;Kate Y. L. Su;E. Young;A. Gáspár
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作者：
Z. Balog;N. Siegler;G. Rieke;László L. Kiss;J. Muzerolle;R. Gutermuth;C. Bell;J. Vinkó;Kate Y. L. Su;E. Young;A. Gáspár
我们展示了新的深 UBVRI 图像和高分辨率多目标光学光谱，这些年轻的（∼6-10 Myr 老）相对较近（800 个）疏散星团 IC 2395。我们识别了近 300 个星团成员，并使用光度测定来估计它们的光谱类型，从早期 B 延伸到中期 M。我们还使用 Spitzer Space 上的 IRAC 和 MIPS 仪器对中心区域进行了红外成像调查 望远镜，覆盖波长范围3.6至24μm。我们的红外观测使我们能够探测到星周盘中的尘埃，这些尘埃的典型半径范围是距中心恒星约0.1至约10个天文单位。我们确定了 18 个 II 类、8 个过渡磁盘和 23 个碎片磁盘候选者，分别占集群成员的 6.5%、2.9% 和 8.3% 具有适当的数据。我们对过渡盘的识别采用相同的标准，以识别年龄从 ∼1 到 ∼18 Myr 的其他 19 个星团和星团。我们发现，处于过渡阶段的圆盘数量占 24 μm 强过量 ([8] – [24] ≥ 1.5) 的圆盘数量从 ∼3 Myr 时的 (8.4 ± 1.3)% 增加到 ∼10 Myr 时的 (46 ± 5)%。过渡磁盘的替代定义将产生不同的百分比，但应显示相同的趋势。
We present new deep UBVRI images and high-resolution multi-object optical spectroscopy of the young (∼6–10 Myr old), relatively nearby (800 pc) open cluster IC 2395. We identify nearly 300 cluster members and use the photometry to estimate their spectral types, which extend from early B to middle M. We also present an infrared imaging survey of the central region using the IRAC and MIPS instruments on board the Spitzer Space Telescope, covering the wavelength range from 3.6 to 24 μm. Our infrared observations allow us to detect dust in circumstellar disks originating over a typical range of radii from ∼0.1 to ∼10 au from the central star. We identify 18 Class II, 8 transitional disk, and 23 debris disk candidates, respectively, 6.5%, 2.9%, and 8.3% of the cluster members with appropriate data. We apply the same criteria for transitional disk identification to 19 other stellar clusters and associations spanning ages from ∼1 to ∼18 Myr. We find that the number of disks in the transitional phase as a fraction of the total with strong 24 μm excesses ([8] – [24] ≥ 1.5) increases from (8.4 ± 1.3)% at ∼3 Myr to (46 ± 5)% at ∼10 Myr. Alternative definitions of transitional disks will yield different percentages but should show the same trend.