The structure and momentum of multiple collimated outflows in the protoplanetary nebula Frosty Leo
Sahai R., Bujarrabal V., Castro-Carrizo A.,
Zijlstra A.A.
Astronomy and Astrophysics, Vol. 360, p.L9-L12 (2000)
Abstract
We have discovered multiple jet-like features in the inner regions of
the protoplanetary nebula (PPN) Frosty Leo, in optical images obtained
with the Hubble Space Telescope. Frosty Leo is only the second PPN
(after CRL2688) and the first oxygen-rich one, to show well-focussed
jets close to the equatorial plane. The nebula consists of two bright
compact structures embedded inside two large tenuous bubbles, separated
by a flaring, roughly edge-on disk. The relatively high surface
brightnesses of two ansae and substructures in the jets imply that the
latter have carved out holes in the optically thick central region of
the nebula, allowing starlight to escape with very little attenuation.
Millimeter-wave CO line observations with the IRAM 30m radiotelescope
show the presence of slow (approximately 10 km s-1) and fast (>50
km s-1) components in a molecular outflow associated with the
bright inner (< 10'') regions of the nebula.
The mechanical momentum in the fast outflow is about a factor 500 larger
than that available from the stellar radiation (L/c) during the post-AGB
life of the source, and most likely derives from the gravitational
energy of a close binary central star.
Full paper (postscript, 950 kb)