Kinematic identification of young nearby moving groups from a sample of chromospherically active stars in the RAVE catalog

TL;DR

This study identifies young, nearby moving groups by analyzing the kinematic signatures of chromospherically active stars in the RAVE catalog, revealing potential new members and confirming known groups.

Contribution

Introduces the Cone Method Sampling to detect kinematically cold young moving groups using combined RAVE and GAIA data, identifying new candidate members.

Findings

Detected 646 significant velocity groupings.

Confirmed 75 members of known young moving groups.

Approximately 50% of candidates are younger than 100 Myr.

Abstract

The purpose of this study is the identification of young ($1< age < 100$ Myr), nearby ($d \leqslant100$ pc) moving groups (YNMGs) through their kinematic signature. YNMGs could be the result of the recent dispersal of young embedded clusters, such that they still represent kinematically cold groups, carrying the residual motion of their parental cloud. Using the fact that a large number ($\sim$ 14000) of the RAVE sources with evidence of chromospheric activity, also present signatures of stellar youth, we selected a sample of solar type sources with the highest probability of chromospheric activity to look for common kinematics. We made use of radial velocity information from RAVE and astrometric parameters from GAIA DR2 to construct a 6-dimension position-velocity vector catalog for our full sample. We developed a method based on the grouping of stars with similar orientation of their velocity vectors, which we call the Cone Method Sampling. Using this method, we detected 646 sources with high significance in the velocity space, with respect to the average orientation of artificial distributions made from a purely Gaussian velocity ellipsoid with null vertex deviation. We compared this sample of highly significant sources with a catalog of YNMGs reported in previous studies, which yield 75 confirmed members. From the remaining sample, about 50% of the sources have ages younger than 100 Myr, which indicate they are highly probable candidates to be new members of identified or even other YNMGs in the solar neighborhood.