AAS 201st Meeting, January, 2003
Session 20. Star Formation I
Poster, Monday, January 6, 2003, 9:20am-6:30pm, Exhibit Hall AB

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[20.19] Spectral Imaging of Herbig Ae Stars in Lyman Alpha: Jets, Disk Winds, and Envelopes

B. Woodgate (NASA's GSFC), C. Grady (NOAO, Eureka Scientific, and GSFC), S. Heap (NASA's GSFC), A. Danks (L3-Analytics), G. Vieira (SSAI), T. Gull (NASA's GSFC), A. Brown, E. Wilkinson, G. Harper, G. Herzceg, J. Linsky (U. Colorado)

We present HST/STIS long slit, R=10,000 spectroscopy of 2 Herbig Ae stars at Lyman alpha. HD 104237 is driving a jet which can be traced 1.05" (120 AU) from the star at PA=-28 degrees. The fainter counter jet can be traced 2.8" (320 AU) at PA=152 degrees. As for HD 163296, the wind terminal velocity in Lyman alpha is the velocity of the innermost knot in the jet. This suggests that the high velocity wind component originates in the jet at r<0.025" (2.9 AU). Long slit spectra of the t>10 Myr HD 100546 system reveal extended Lyman alpha, continuum and fluorescent molecular hydrogen emission along both the disk major and minor axes. The emission is symmetric along the system major axis, with Lyman alpha extending 2" (206 AU) from the star. Along the minor axis, emission is seen along the NE side of the star, where it can be traced 3.3" (312 AU) from the star, but is not seen SW of the star. The spatial distribution of emission in this system is consistent with material from the envelope rather than the protoplanetary disk. Unlike the younger Herbig Ae stars, HD 100546 does not appear to be driving a bipolar jet, but instead shows blue-shifted Si III emission, similar to the C III 1175. A emission in beta Pictoris. Si III absorption can be seen in silhouette against the reflection nebulosity and is preferentially observed to the NE of the star along the minor axis where it can be traced 0.65" (68 AU). Over this distance the absorption displaces by 80 km/s, providing the first direct detection of a disk wind. Comparison of the STIS data from the two epochs also reveals that the star is intermittently obscured in Lyman alpha by an opaque cloud blocking the inner 0.3" (30 AU) in our 2002 June observation.

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Bulletin of the American Astronomical Society, 34, #4
© 2002. The American Astronomical Soceity.