The Hercules-Lyra association revisited - New age estimation and multiplicity study

摘要: Context. The Hercules-Lyra association, a purported nearby young moving group, contains few tens of zero age main sequence stars spectral types F to M. existence and the properties Her-Lyr association are controversial have been discussed in literature. Aims. present work reassesses member list based on kinematics indicators. Many objects form multiple systems or low-mass companions so we need properly account for multiplicity. Methods. We use our own new imaging observations archival data identify systems. colors magnitudes kinematic candidates compared isochrones. derive further information Li depletion, rotation, coronal chromospheric activity. A set canonical members is identified infer mean properties. Membership criteria derived from used discard non-members. Results. selected literature belong 35 stellar systems, 42.9% which multiple. Four (V538 Aur, DX Leo, V382 Ser, HH Leo) confirmed this by common proper motion. An orbital solution presented binary system forms hierarchical triple with Leo. Indeed, group displays signatures youth. Seven distribution equivalent widths spread widely similar that Pleiades UMa group. Gyrochronology gives an 257 ± 46 Myr roughly between ages Ursa Major measures activity support age. membership kinematics, lithium width, activity, gyrochronological In total, eleven as certain including co-moving plus additional 23 possible while 14 doubtful can be rejected. comparison mass function, however, indicates presence large number members, remain unidentified.