Birth sites of young stellar associations and recent star formation in a flocculent corrugated disc
Birth sites of young stellar associations and recent star formation in a flocculent corrugated disc
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DOI：
10.1093/mnras/staa3189
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发表时间：
2020-06
影响因子：
4.8
通讯作者：
A. Quillen;A. Pettitt;S. Chakrabarti;Yifan Zhang;J. Gagn'e;I. Minchev
中科院分区：
文献类型：
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作者：
A. Quillen;A. Pettitt;S. Chakrabarti;Yifan Zhang;J. Gagn'e;I. Minchev
通过向后轨道积分，我们估计了太阳邻域中年龄小于 70 Myr 的年轻恒星协会和移动星团的诞生位置。大多数这些恒星协会的诞生位置都位于比太阳更小的银心半径处，这意味着它们的恒星在诞生后径向向外移动。这条规则的例外包括在太阳银河系中心半径之外形成的阿古斯和奥克塔斯协会。恒星协会诞生高度的变化表明它们诞生在分子云的波纹盘中，类似于从当前的丝状分子云分布和尘埃消光图推断的情况。具有不同但接近的共转模式速度和不同高度的多个旋臂特征可以解释恒星关联的诞生地点。我们发现，年轻的恒星协会位于太阳附近恒星的紫外恒星速度分布的峰值之间。如果它们诞生在一个扰动穿过它的恒星轨道的旋臂中，这是可以预料到的。相比之下，恒星缔合体似乎位于垂直相空间分布的峰值附近，这表明恒星缔合体所产生的气体与低速弥散盘恒星一起垂直移动。
With backwards orbit integration we estimate birth locations of young stellar associations and moving groups identified in the solar neighborhood that are younger than 70 Myr. The birth locations of most of these stellar associations are at smaller galactocentric radius than the Sun, implying that their stars moved radially outwards after birth. Exceptions to this rule include are the Argus and Octans associations which formed outside the Sun's Galactocentric radius. Variations in birth heights of the stellar associations suggest that they were born in a corrugated disk of molecular clouds, similar to that inferred from the current filamentary molecular cloud distribution and dust extinction maps. Multiple spiral arm features with different but near corotation pattern speeds and at different heights could account for the stellar association birth sites. We find that the young stellar associations are located in between peaks in the UV stellar velocity distribution for stars in the solar neighborhood. This would be expected if they were born in a spiral arm which perturbs stellar orbits that cross it. In contrast, stellar associations seem to be located near peaks in the vertical phase space distribution, suggesting that the gas in which stellar associations are born moves vertically together with the low velocity dispersion disk stars.