A kinematically unbiased search for nearby young stars in the Northern hemisphere selected using SuperWASP rotation periods

作者：Binks A S^*; Jeffries R D; Maxted P F L

来源：Monthly Notices of the Royal Astronomical Society, 2015, 452(1): 173-192.

DOI：10.1093/mnras/stv1309

• stars: late-type
• stars: pre-main-sequence

We present a kinematically-unbiased search to identify young, nearby low-mass members of kinematic moving groups (MGs). Objects with both rotation periods shorter than 5 d in the SuperWASP All-Sky Survey and X-ray counterparts in the ROSAT All-Sky Survey were chosen to create a catalogue of several thousand rapidly rotating, X-ray active FGK stars. These objects are expected to be either young single stars or tidally locked spectroscopic binaries. We obtained optical spectra for a sub-sample of 146 stars to determine their ages and kinematics, and in some cases repeat radial velocity measurements were used to identify binarity. 26 stars are found to have lithium abundances consistent with an age of <= 200 Myr, and show no evidence for binarity and in most cases measurements of H alpha and nu sin i support their youthful status. Based on their youth, their radial velocities and estimates of their three-dimensional kinematics, we find 11 objects that may be members of known MGs, eight that do not appear associated with any young MG and a further seven that are close to the kinematics of the recently proposed 'Octans-Near' MG, and which may be the first members of this MG found in the Northern hemisphere. The initial search mechanism was similar to 18 per cent efficient at identifying likely-single stars younger than 200 Myr, of which 80 per cent were early-K spectral types.

• 出版日期2015-9-1