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C.A. Grady, D. Devine (NOAO/STIS, NASA/GSFC), B. Woodgate, A. Boggess (LASP, NASA/GSFC), F. C. Bruhweiler (CUA), M. Clampin (STScI)
STIS GTO broad-band (2000-10000 Å) optical coronagraphic imaging of the 6 Myr old Herbig Ae star, HD 163296, in September 1998 has revealed two faint, emission-line nebulae located 1050 AU northeast and 900 AU southwest of HD 163296. The emission features lie along the rotation axis of the disk associated with HD 163296, and are morphologically similar to Herbig-Haro objects. The candidate HH objects have angular sizes of ~1"x1".The NE object having a flux ~1x10-15 ergs cm-2 s-1. Both the sizes and the flux are typical of HH objects. Comparison of a moderate resolution, FUV HST STIS 0.2"x0.06" aperture spectrum with archival IUE data indicates that much of the Lyman alpha emission is spatially extended, on scales larger than 7x24 AU. Collectively, the data are consistent with the presence of a collimated outflow. Similar collimated outflows have previously been reported only for PMS stars an order of magnitude younger than HD 163296.
Assuming the candidate HH objects have velocities similar to the high velocity component of HD 163296's stellar wind, the ejection event responsible for the NE object occurred ~12 years ago. Therefore, the mass ejection event responsible for the HH candidates may correspond to the higher wind state sampled by IUE in 1986 and 1987.
This study was supported by HST STIS GTO funding through support to AURA/NOAO in response to NASA A/O OSSA-4-84 through the Hubble Space Telescope Project at GSFC. Analysis of the HST STIS and IUE data was carried out in the Laboratory for Astronomy & Solar Physics, NASA/GSFC.
The author(s) of this abstract have provided an email address for comments about the abstract: cgrady@echelle.gsfc.nasa.gov