On the diversity and statistical properties of protostellar discs
On the diversity and statistical properties of protostellar discs
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DOI：
10.1093/mnras/sty169
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发表时间：
2018-04-01
影响因子：
4.8
通讯作者：
Bate, Matthew R.
中科院分区：
文献类型：
--
作者：
Bate, Matthew R.
我们提出了原恒星盘的第一个种群合成研究的结果。我们分析了在星团形成的辐射流体动力学模拟中形成的大样本原恒星盘的演化和性质。由于恒星形成过程的混沌性质，我们发现了大量不同的年轻原恒星盘，包括未对准的盘和方向随时间变化的盘。星盘相互作用使星盘截短并产生多个系统。盘可能在动力碰撞和/或撞击压力剥离中被破坏，但随后的气体吸积会使其重新形成。我们量化了原恒星年龄约为10(5)年的盘质量和半径分布。对于低质量的原恒星，盘质量倾向于随着年龄和原恒星质量的增加而增加。盘的半径从10到几百天文单位不等，在小于或接近10(4)年的时间尺度上增大，在低质量原恒星周围变小。孤立的原恒星盘的径向表面密度分布比最小质量太阳星云模型更平坦，通常缩放成与r（-1）成比例的Sigma。盘与原恒星的质量比很少超过2，典型的范围是M-d/M-* = 0.1-1，年龄小于或接近10(4)年，此后逐渐减小。我们量化了星周盘和束缚对原恒星轨道的相对取向角，发现随着分离的减少，对排列的偏好增强。我们还研究了孤立的原恒星和对的圆盘外部部分的方向与原恒星和内部圆盘旋转的不同。
We present results from the first population synthesis study of protostellar discs. We analyse the evolution and properties of a large sample of protostellar discs formed in a radiation hydrodynamical simulation of star cluster formation. Due to the chaotic nature of the star formation process, we find an enormous diversity of young protostellar discs, including misaligned discs, and discs whose orientations vary with time. Star-disc interactions truncate discs and produce multiple systems. Discs may be destroyed in dynamical encounters and/or through ram-pressure stripping, but reform by later gas accretion. We quantify the distributions of disc mass and radii for protostellar ages up to approximate to 10(5) yr. For low-mass protostars, disc masses tend to increase with both age and protostellar mass. Disc radii range from of order 10 to a few hundred au, grow in size on time-scales less than or similar to 10(4) yr, and are smaller around lower mass protostars. The radial surface density profiles of isolated protostellar discs are flatter than the minimum mass solar nebula model, typically scaling as Sigma proportional to r(-1). Disc to protostar mass ratios rarely exceed two, with a typical range of M-d/M-* = 0.1-1 to ages less than or similar to 10(4) yr and decreasing thereafter. We quantify the relative orientation angles of circumstellar discs and the orbit of bound pairs of protostars, finding a preference for alignment that strengths with decreasing separation. We also investigate how the orientations of the outer parts of discs differ from the protostellar and inner disc spins for isolated protostars and pairs.