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arXiv 0808.2273astro-ph
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HD 181327周围可能存在的冰态柯伊伯带

A Possible Icy Kuiper Belt around HD 181327

Christine H. Chen, Michael P. Fitzgerald, Paul S. Smith

摘要:

我们已经获得了双子座南T-ReCS Qa波段(18.3微米)的图像和斯皮策MIPS SED模式观测的HD 181327,一个F5/F6 V成员的~12万年的老β Picture移动群。我们解决了磁盘的热发射的第一次,并发现,磁盘的北臂是1.4倍比南部arm. In明亮,此外,我们检测到一个宽峰合并斯皮策IRS和MIPS光谱在60 - 75微米,可能产生的发射从结晶水冰。我们使用无定形橄榄石和水冰粒的尺寸分布(dn/da与α ^{-2.25}成比例,a_{min}与最小爆裂尺寸一致,a_{max} = 20微米)模拟IRS和MIPS数据,这些冰粒位于距离中心恒星86.3天文单位的位置,正如先前发表的散射光图像所观察到的那样。由于光解吸寿命为冰冷的粒子是~1400年,显着小于估计的~ 1200万年的年龄的系统,我们假设,我们已经检测到的碎片,可能是稳定的补充之间的碰撞冰冷的柯伊伯带对象的母体在一个新形成的行星系统。

英文摘要:

We have obtained a Gemini South T-ReCS Qa-band (18.3 micron) image and a Spitzer MIPS SED-mode observation of HD181327, an F5/F6V member of the ~12 Myr old beta Pictoris moving group. We resolve the disk in thermal-emission for the first time and find that the northern arm of the disk is 1.4x brighter than the southern arm. In addition, we detect a broad peak in the combined Spitzer IRS and MIPS spectra at 60 - 75 micron that may be produced by emission from crystalline water ice. We model the IRS and MIPS data using a size distribution of amorphous olivine and water ice grains (dn/da proportional to a^{-2.25} with a_{min} consistent with the minimum blow out size and a_{max} = 20 micron) located at a distance of 86.3 AU from the central star, as observed in previously published scattered-light images. Since the photo-desorption lifetime for the icy particles is ~1400 yr, significantly less than the estimated ~12 Myr age of the system, we hypothesize that we have detected debris that may be steadily replenished by collisions among icy Kuiper belt object-like parent bodies in a newly forming planetary system.

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