Poster abstract details

A new statistical distance scale based on MSX data
R. Ortiz, M.V.F. Copetti and S. Lorenz-Martins

Abstract

Statistical distance scales, when correctly evaluated, constitute a robust alternative if they are based on a large sample with accurate observational parameters. Nevertheless many methods available in the literature make use of visual data that are severely affected by reddening.
In this work we propose a statistical method based on a relationship between the age and the specific intensity of the radiation emitted in the MSX bands.
An analysis of some theoretical evolutionary models shows that, during the first $2 imes 10^3$ years, the nebular radius seems to increase at a nearly constant rate. This effect occurs because even though the various gas shells expand at different velocities, they might be observed as a single shell in radio images, for example.
Distances are evaluated for a hundred objects in various directions of the Galactic disc. The present method is
especially suited for young, compact planetary nebulae in the Galactic disc, severely affected by
interstellar extinction.