High Proper Motion Features in the Central Orion Nebula

Abstract

The brightest portion of the Orion Nebula has been reimaged with the Hubble Space Telescope in Hα, [N II], and [O III]. Comparison with earlier Wide Field Planetary Camera 2 images going back as much as 8 yr has allowed determination of tangential velocities (proper motions) down to about 10 km s^-1 for a variety of sources. Multiple outflow systems are found associated with individual proplyds in the ionized portion of the nebula (HH 518, HH 624, possibly HH 507). The Orion-S complex of radio and infrared sources is the source of multiple outflows. A new outflow system (HH 625) has been identified as coming from the blueshifted portion of the imbedded high velocity CO flow coming from the Orion-S region, this object having CO, H₂, and low ionization optical components. The low velocity CO outflow originating from or near FIR 4 is the likely source of HH 530. A new imbedded source is inferred from this optical data to lie in Orion-S. This optical outflow source (OOS) clearly feeds the systems HH 269 and HH 529, which lie along a straight line. There is evidence that this is also the source for HH 528, HH 202, and HH 203/204, all of which are blueshifted (except possibly HH 528 whose radial velocity is unknown). There is no strong radio, infrared, or X-ray source within the positional ellipse of the OOS. Based in part on observations with the NASA/ESA Hubble Space Telescope, obtained at the Space Telescope Science Institute, which is operated by the Association of Universities for Research in Astronomy, Inc., under NASA contract NAS 5-26555.