Optical spectroscopy of X-ray sources in the old open cluster M 67 ?

@inproceedings{Berg1999OpticalSO,
  title={Optical spectroscopy of X-ray sources in the old open cluster M 67 ?},
  author={Maureen van den Berg and Frank W. M. Verbunt and Robert D. Mathieu},
  year={1999}
}
We have obtained optical spectra of seven stars in the old galactic cluster M 67 that are unusual sources of X-rays, and investigate whether the X-ray emission is due to magnetic activity or to mass transfer. The two binaries below the giant branch S 1063 and S 1113, the giant with the white dwarf companion S 1040 and the eccentric binary on the subgiant… CONTINUE READING