HST and VLT observations of the Symbiotic Star Hen 2-147

M. Santander-Garcia; R. L. M. Corradi; P. A. Whitelock; U. Munari; A. Mampaso; F. Marang; F. Boffi; M. Livio

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HST and VLT observations of the Symbiotic Star Hen 2-147

M. Santander-Garcia·R. L. M. Corradi·P. A. Whitelock·U. Munari·A. Mampaso·F. Marang·F. Boffi·M. Livio

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Abstract

We investigate the dynamics of the nebula around the symbiotic star Hen 2-147, determine its expansion parallax, and compare it with the distance obtained via the Period-Luminosity relation for its Mira variable. The geometry of the nebula is found to be that of a knotty annulus of ionized gas inclined to the plane of sky and expanding with a velocity of ~90 km/s. A straightforward application of the expansion parallax method provides a distance of 1.5+-0.4 kpc, which is a factor of two lower than the distance of 3.0+-0.4 kpc obtained from the Period-Luminosity relationship for the Mira (which has a pulsation period of 373 days). The discrepancy is removed if, instead of expanding matter, we are observing the expansion of a shock front in the plane of the sky. This shock interpretation is further supported by the broadening of the nebular emission lines.

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M. Santander-Garcia, R. L. M. Corradi, P. A. Whitelock, U. Munari, A. Mampaso, F. Marang, F. Boffi, M. Livio. 2007-01-14. HST and VLT observations of the Symbiotic Star Hen 2-147. https://arxiv.org/abs/astro-ph/0701404

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