# Hen 2-104: A close-up look at the Southern Crab - Astrophysics

Hen 2-104: A close-up look at the Southern Crab - Astrophysics - Descarga este documento en PDF. Documentación en PDF para descargar gratis. Disponible también para leer online.

Abstract: The kinematics, shaping, density distribution, expansion distance, andionized mass of the nebula Hen 2-104, and the nature of its symbiotic Mira areinvestigated. A combination of multi-epoch HST images and VLT integral fieldhigh-resolution spectroscopy is used to study the nebular dynamics both alongthe line of sight and in the plane of the sky. These observations allow us toconstruct a 3-D spatio-kinematical model of the nebula, which together with themeasurement of its apparent expansion in the plane of the sky over a period of4 years, provides the expansion parallax for the nebula. The integral fielddata featuring the S{\sc ii} $\lambda\lambda$671.7,673.1 emission linedoublet provide us with a density map of the inner lobes of the nebula, whichtogether with the distance estimation allow us to estimate its ionized mass. Wefind densities ranging from n$e$=500 to 1000 cm$^{-3}$ in the inner lobes andfrom 300 to 500cm$^{-3}$ in the outer lobes. We determine an expansion parallaxdistance of 3.3$\pm$0.9 kpc to Hen 2-104, implying an unexpectedly largeionized mass for the nebula of the order of one tenth of a solar mass.

Autor: M. Santander-Garcia, R. L. M. Corradi, A. Mampaso, C. Morisset, U. Munari, M. Schirmer, B. Balick, M. Livio

Fuente: https://arxiv.org/