Ejection processes in the young open cluster NGC 2264. A study of the
  [OI]{\lambda}6300 emission line
  We search for correlations between the [OI]6300 line, a well-known tracer of
jets and winds in young stars, and stellar/disk/accretion properties in the
young cluster NGC 2264, aiming to characterize the outflow phenomena that occur
within the circumstellar environment. We analyzed FLAMES spectra of 184 stars,
detecting the [OI]6300 line in 108 CTTSs and 2 Herbig AeBe stars. We identified
the main features of this line: a high-velocity component (HVC), and a broad
and narrow low-velocity components (BLVC and NLVC). We calculated their
luminosities and kinematic properties, then compared with stellar/accretion
parameters. The luminosity of the [OI]6300 line correlates positively with the
stellar and accretion luminosity. The HVC is only detected among systems with
optically thick inner disks; the BLVC is found in thick disk systems and few
systems with anemic disks; and the NLVC is common among systems with all types
of disks. Our BLVCs present blueshifts of up to 50km/s and widths compatible
with an origin 0.05au-0.5au from the star, while the NLVCs in our sample have
widths compatible with an origin between 0.5au and 5au, in agreement with
previous studies in Taurus. The HVC is found most often among sources with
irregular, aperiodic photometric variability, usually associated with accretion
in an unstable regime. No stellar properties appear to significantly influence
any property of these jets. We find jet velocities on average similar to those
found in Taurus. We confirm earlier findings in Taurus which favor an inner MHD
disk wind as the origin of the BLVC, while there is no conclusive evidence that
the NLVC traces photoevaporative disk winds. The [OI]6300 line profile shows
signs of evolving as the disk disperses, with the HVC and BLVC disappearing as
the inner disk becomes optically thin, in support of the scenario of inside-out
gas dissipation in the inner disk.
