Scorpius-Centaurus K-Type Stars

Using an X-ray, proper motion and color-magnitude selected sample, we obtained spectra for 361 stars, for which we report spectral classifications and Li and Ha equivalent widths. We identified 156 new members of Sco-Cen, and recovered 51 previously published members.

We have combined these with previously known members to form a sample of 493 solar-mass (~0.7-1.3M_[sun}_) members of Sco-Cen.We investigated the star-formation history of this sample, and re-assessed the ages of the massive main-sequence turn-off and the G-type members in all three subgroups. We performed a census for circumstellar disks in our sample using WISE infrared data and find a protoplanetary disk fraction for K-type stars of 4.4^+1.6^_-0.9_% for Upper Centaurus-Lupus and Lower Centaurus-Crux at ~16Myr and 9.0^+0.4^_-2.2_% for Upper Scorpius at~10Myr.