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arXiv 1606.01247astro-ph.EPastro-ph.SR
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$β$ Picture碎片盘中产生的气体演化的自洽模型

A self-consistent model for the evolution of the gas produced in the debris disc of $β$ Pictoris

Quentin Kral, Mark Wyatt, Robert Carswell, Jim Pringle, Luca Matra, Attila Juhasz

摘要:

本文提出了一个描述$β$ Picture碎片盘气体演化的自洽模型。我们的模型提出,原子碳和氧是从CO的光解,这本身是释放的挥发物丰富的机构在碎片盘由于颗粒颗粒碰撞或光解吸。当CO持续不到一个轨道时,原子气体通过粘性扩散而演化,导致母带内部的吸积盘和外部的递减盘。的温度,电离分数和人口水平的碳和氧的光解离区域模型多云,这是耦合到一个动态粘性$α$模型。我们提出了新的气体观测的$β$ Pic,C I观察到的APEX和O I观察到的赫歇尔,并表明,这些随着公布的C II和CO的观测都可以解释这个新的模型。我们的模型需要一个粘度$α$ > 0.1,类似于发现在充分电离的光盘的其他天体,我们建议,磁旋转的不稳定性是在发挥这种高度电离和稀释介质。这个新模型可以用高分辨率ALMA观测的CI的预报来检验。我们还对$β$图中的星子的含水量进行了约束。这里提出的设想可能适用于所有碎片盘,这种模式可更普遍地用于所有探测到碳、氧或一氧化碳的碎片盘。

英文摘要:

This paper presents a self-consistent model for the evolution of gas produced in the debris disc of $β$ Pictoris. Our model proposes that atomic carbon and oxygen are created from the photodissociation of CO, which is itself released from volatile-rich bodies in the debris disc due to grain-grain collisions or photodesorption. While the CO lasts less than one orbit, the atomic gas evolves by viscous spreading resulting in an accretion disc inside the parent belt and a decretion disc outside. The temperature, ionisation fraction and population levels of carbon and oxygen are followed with the photodissociation region model Cloudy, which is coupled to a dynamical viscous $α$ model. We present new gas observations of $β$ Pic, of C I observed with APEX and O I observed with Herschel, and show that these along with published C II and CO observations can all be explained with this new model. Our model requires a viscosity $α$ > 0.1, similar to that found in sufficiently ionised discs of other astronomical objects; we propose that the magnetorotational instability is at play in this highly ionised and dilute medium. This new model can be tested from its predictions for high resolution ALMA observations of C I. We also constrain the water content of the planetesimals in $β$ Pic. The scenario proposed here might be at play in all debris discs and this model could be used more generally on all discs with C, O or CO detections.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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