The CO structure of NGC 7027 - A bipolar nebula in the making

Phillips, J. P.; Mampaso, A.; Williams, P. G.; Ukita, N.
Referencia bibliográfica

Astronomy and Astrophysics (ISSN 0004-6361), vol. 247, no. 1, July 1991, p. 148-156. Research supported by DGICYT.

Fecha de publicación:
7
1991
Número de autores
4
Número de autores del IAC
2
Número de citas
16
Número de citas referidas
15
Descripción
Intermediate resolution mapping and limited off-center spectroscopy of the post-main-sequence molecular outflow source NGC 7027 are presented. The CO envelope is found to have a deconvolved FWHM of 35 x 34 sq arcsec, while core CO profiles are shown to display a steep-sided triple-peaked asymmetric configuration different from previous lower resolution results. It is argued that the overall shell structure is not tilted in the spatial-velocity plane, and that the larger part of the outflow is well represented in terms of a spherically-symmetric constant-velocity envelope. A model is constructed in which H I outflow densities are enhanced within an 'equatorial' disk-constraining expansion of the H II region and result in the observed cylindrical ionized structure. The probable further evolution of this source, and the likely formation of a bipolar configuration similar to NGC 6302 are discussed.