Bibcode
Orsatti, A. M.; Vergne, M. M.; Feinstein, C.; Martínez, R. E.
Referencia bibliográfica
Exploiting Large Surveys for Galactic Astronomy, 26th meeting of the IAU, Joint Discussion 13, 22-23 August 2006, Prague, Czech Republic, JD13, #12
Fecha de publicación:
8
2006
Número de citas
0
Número de citas referidas
0
Descripción
We present preliminary results from the Open Cluster Polarimetric
Survey. The aim of the survey is to provide clues about the
characteristics of the dust responsible for extinction and polarization
in the light from cluster members, about its spatial distribution and
also about possible memberships. Our data on linear optical polarimetry
were obtained at the Complejo Astronómico "El Leoncito" (CASLEO,
San Juan, Argentina). The observations were carried out using the Torino
five-channel photopolarimeter attached to the 2.15-m. Each star was
observed simultaneously through the Johnson-Cousins broad band UBVRI
filters. At the present stage we have covered a total of 17 open
clusters with galactic longitudes between l=294 and l =360 degrees in
the Southern Milky Way, with a range in distance of about 800-2300 pcs,
and we have observed about 500 individual stars.
For each of these open clusters, we have been able to detect the
presence (if any) of intracluster dust and the interstellar dust
distribution on direction to the cluster, with auxiliary observations of
non-member stars on the same direction. Other information we got from
the polarimetric observations is the mean grain size of the dust clouds
and the mean direction of the magnetic field at the clusters position.
Additionally, the polarimetry data can be used as a powerful criterion
for determining the membership in a galactic cluster and for detecting
the location of an energetic phenomenon occurred in the past of a
cluster. A very important by-product of these studies is the isolation
of stars displaying polarization of a non-interstellar origin: that is,
stars with extended atmospheres (like Be stars), dust associated to
possible binary systems, or surrounding the star (due to evolution or as
a formation remnant). In the present study we will emphasize about:
1)Spatial distribution of the observed open clusters 2)General
polarimetric characteristics of the nearby dust clouds 3)Distribution of
the dust clouds on the line of sight to the clusters 4) stars with
intrinsic polarization and their general characteristics.