Previous   |   Session 175   |   Next  |   Author Index   |   Block Schedule

[175.01] Ly\alpha Pumped Molecular Hydrogen Emission in the Planetary Nebulae NGC 6853 and NGC 3132

R. E. Lupu, K. France, S. R. McCandliss (Johns Hopkins University)

We report the first detection of Ly\alpha pumped molecular hydrogen emission in planetary nebulae, based on FUSE observations of NGC 6853 (905--1187~Å) and HUT observations of NGC 3132 (820--1840~Å). The atypical H₂ emission observed in the spectra of NGC 6853 and NGC 3132 can be explained by excitation of vibrationally hot H₂ by Ly\alpha photons. In both cases, the detected H₂ lines require a temperature in the 2000 K range and a ~ 0.33 Å\ wide Ly\alpha with a deep self-reversal. These parameters satisfy both short and long wavelength constraints, pointing to similar conditions of the gas in the two nebulae. The H₂ and \ion{H}{1} column densities as well as the Doppler shifts of the molecular and atomic components with respect to the nebular Ly\alpha are estimated in each case.

FUSE data were obtained under the Guest Investigator Program (NASA grant NNGO4GK82G) by the NASA-CNES-CSA FUSE mission, operated by the Johns Hopkins University.

Previous   |   Session 175   |   Next

Bulletin of the American Astronomical Society, 37 #4
© 2005. The American Astronomical Soceity.