Internal motions in OB-associations with Gaia DR2статья
Статья опубликована в высокорейтинговом журнале
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Дата последнего поиска статьи во внешних источниках: 25 ноября 2020 г.
Аннотация:We study the motions inside 28 OB-associations with the use ofGaia DR2 proper motions. The average velocity dispersioncalculated for 28 OB-associations including more than 20 starswith Gaia DR2 proper motion is sigma_v =4.5 kms-1. The median virial and stellar masses of OB-associationsare M_vir=8.9 x 10^5 and M_st=8.1 x 10^3Ms, respectively. The median star-formation efficiency inparent giant molecular clouds appears to be epsilon=1.2%.Gaia DR2 proper motions confirm the expansion in thePer OB1, Car OB1 and Sgr OB1 associations found earlier with Gaia DR1 data. We also detect the expansion in Gem OB1, Ori OB1and Sco OB1 associations which became possible for the firsttime now when analyzed with Gaia DR2 proper motions. Theanalysis of the distribution of OB-stars in the Per OB1association shows the presence of a shell-like structure with theradius of 40 pc. Probably, the expansion of the Per OB1association started with the velocity greater than the present-dayexpansion velocity equal to 5.0 +/- 1.7 km s-1.