The impact of bar origin and morphology on stellar migration
The impact of bar origin and morphology on stellar migration
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棒的起源和形态对恒星迁移的影响
DOI：
10.1093/mnras/stad3377
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发表时间：
2024
影响因子：
4.8
通讯作者：
Iles E
中科院分区：
文献类型：
--
作者：
Iles E
驱动棒结构形成的不同机制表明，棒的起源在星系的恒星群中应该是可以区分的。为了研究这些起源如何影响不同的棒形态并影响恒星轨道和迁移，我们分析了三个模拟盘，它们代表了由盘不稳定性和相互作用驱动的潮汐发展引起的孤立演化下的棒形成。第一个孤立盘和潮汐驱动盘产生相似的杆结构，而第二个孤立盘由没有伴星的潮汐初始条件生成，明显不同。评估径向和垂直位置、盘平面角动量、轨道偏心率和随后的盘金属丰度的变化，以及对恒星年龄和形成半径的依赖性。棒起源是可区分的，潮汐盘总体上表现出较大的迁移，内盘和外盘之间的金属丰度差异较高，并且内盘恒星群移位到大半径并低于盘平面。最近距离对这一时期之前、之后和期间形成的恒星群的影响是显而易见的。然而，条形形态也被发现是盘恒星性质演化的一个重要因素，相似的条形在随半径的迁移趋势上产生相似的特征，特别是在垂直恒星运动和中心金属丰度特征的演化中。
Different mechanisms driving bar structure formation indicate that bar origins should be distinguishable in the stellar populations of galaxies. To study how these origins affect different bar morphologies and impact stellar orbits and migration, we analyse three simulated discs which are representative of bar formation under isolated evolution motivated by disc instability, and interaction-driven tidal development. The first isolated disc and the tidally driven disc produce similar bar structure, while the second isolated disc, generated by the tidal initial condition without the companion, is visibly dissimilar. Changes to radial and vertical positions, angular momentum in the disc-plane, orbital eccentricity, and the subsequent disc metallicities are assessed, as is the dependence on stellar age and formation radii. Bar origin is distinguishable, with the tidal disc displaying larger migration overall, higher metallicity difference between the inner and outer disc, and a population of inner disc stars displaced to large radii and below the disc-plane. The effect of closest approach on populations of stars formed before, after, and during this period is evident. However, bar morphology is also found to be a significant factor in the evolution of disc stellar properties, with similar bars producing similar traits in migration tendency with radius, particularly in vertical stellar motion and in the evolution of central metallicity features.