文章基本信息

标题：Expanding associations in the Vela-Puppis region
其他标题：3D structure and kinematics of the young population⋆
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作者：T. Cantat-Gaudin ; C. Jordi ; N. J. Wright 等
期刊名称：Astronomy & Astrophysics
印刷版ISSN：0004-6361
电子版ISSN：1432-0746
出版年度：2019
卷号：626
DOI：10.1051/0004-6361/201834957
语种：English
出版社：EDP Sciences
摘要：Context. The Vela-Puppis region is known to host the Vela OB2 association as well as several young clusters featuring OB and pre-main-sequence stars. Several spatial and kinematic subgroups have been identified in recent years.Aims. By grouping stars based on their positions and velocity, we can address the question of the dynamical history of the region and the mechanisms that drove stellar formation. TheGaiaDR2 astrometry and photometry enables us to characterise the 3D spatial and 3D kinematic distribution of young stars and to estimate the ages of the identified components.Methods. We used an unsupervised classification method to group stars based on their proper motions and parallax. We studied the expansion rates of the different identified groups based on 3D velocities and on corrected tangential velocities. We used theoretical isochrones to estimate ages.Results. The young stars can be separated into seven main groups of different ages and kinematical distribution. All groups are found to be expanding, although the expansion is mostly not isotropic.Conclusions. The size of the region, the age substructure, and the anisotropic expansion rates are compatible with a prolonged period of star formation in a turbulent molecular cloud. The current kinematics of the stars cannot be explained by internal processes alone (such as gas expulsion).
关键词：enopen clusters and associations: individual: Vela OB2open clusters and associations: individual: Trumpler 10open clusters and associations: individual: NGC 2547open clusters and associations: individual: NGC 2451Bstars: pre-main sequence