Transience of Hot Dust around Sun-like Stars
Transience of Hot Dust around Sun-like Stars
复制标题
类太阳恒星周围热尘埃的瞬息
DOI：
10.1086/510999
复制
发表时间：
2006
期刊：
影响因子：
--
通讯作者：
C. Lisse
中科院分区：
文献类型：
--
作者：
M. Wyatt;Roger M. H. Smith;J. Greaves;C. Beichman;C. Beichman;G. Bryden;C. Lisse
本文发展了一个简单的碰撞碎片盘稳态演化模型，并讨论了7颗具有<10 Au热尘的类太阳恒星的新星群的性质。该模型表明，在给定的年龄有一个最大可能的磁盘质量，因为更大的原始磁盘处理他们的质量更快。相应的最大尘埃光度为fmax = 0.16 × 10- 3r ~ 7/3 t，其中r为Au的盘半径，tag为百万年的系统年龄。大部分（4/7）的热盘都超过了这个极限1000光年，因此不可能是大质量小行星带的产物;相反，以下系统必须经历短暂的事件，其特征是星星附近异常高的尘埃含量：η Corvi，HD 69830，HD 72905和BD +20 307。它还表明，热尘埃不能起源于最近的碰撞中的小行星带，因为也有一个最大的速度，在足够大的碰撞复制一个给定的尘埃光度可以发生。在这些系统中，供给尘埃的微行星带必须比尘埃离星星更远，通常在102 Au。四个热尘系统的其他显著特征如下：其中两个（η Corvi和HD 72905）也有一个大于10 Au的小行星带;一个（HD 69830）有三个小于1 Au的海王星质量的行星;所有都表现出强烈的中红外硅酸盐特征。我们认为这种短暂的尘埃最有可能的起源是一种动力学不稳定性，这种动力学不稳定性在类似于我们自己系统中晚期重撞击的事件中从更远的星子带向内散射星子，尘埃在碰撞和升华中从这些星子中释放出来。
In this paper a simple model for the steady state evolution of debris disks due to collisions is developed and confronted with the properties of the emerging population of seven Sun-like stars that have hot dust at <10 AU. The model shows that there is a maximum possible disk mass at a given age, since more massive primordial disks process their mass faster. The corresponding maximum dust luminosity is fmax = 0.16 × 10-3r7/3t, where r is disk radius in AU and tage is system age in Myr. The majority (4/7) of the hot disks exceed this limit by ≫1000 and so cannot be the products of massive asteroid belts; rather, the following systems must be undergoing transient events characterized by an unusually high dust content near the star: η Corvi, HD 69830, HD 72905, and BD +20 307. It is also shown that the hot dust cannot originate in a recent collision in an asteroid belt, since there is also a maximum rate at which collisions of sufficient magnitude to reproduce a given dust luminosity can occur. The planetesimal belt feeding the dust in these systems must be located farther from the star than the dust, typically at ≫2 AU. Other notable properties of the four hot dust systems are as follows: two also have a planetesimal belt at >10 AU (η Corvi and HD 72905); one has three Neptune mass planets at <1 AU (HD 69830); all exhibit strong mid-IR silicate features. We consider the most likely origin for this transient dust to be a dynamical instability that scattered planetesimals inward from a more distant planetesimal belt in an event akin to the late heavy bombardment in our own system, the dust being released from such planetesimals in collisions and sublimation.
影响因子：
3.2
作者：
V. Mannings;A. Boss;S. Russell
通讯作者：
V. Mannings;A. Boss;S. Russell