IAFE   05512
INSTITUTO DE ASTRONOMIA Y FISICA DEL ESPACIO
Unidad Ejecutora - UE
congresos y reuniones científicas
Título:
CCD Washington photometry of galactic open clusters: the moderately metal-poor cluster NGC 2236
Autor/es:
CLARIA OLMEDO, JUAN JOSÉ; PIATTI, ANDRÉS E.; PARISI, M.C.; AHUMADA, A.V.
Lugar:
Venezuela
Reunión:
Congreso; Reunión Regional Latinoamericana de Astronomía; 2007
Resumen:
We present $CCD$ Washington $CT_{1}$ photometry for 1262 stars in the field of the open cluster NGC\,2236. These data were supplemented with photoelectric $CMT_{1}T_{2}$ photometry of 13 red giant candidates. The comparison of the cluster $(T_{1},C-T_{1})$ colour-magnitude diagram with theoretical isochrones computed for the Washington system yields $E(C-T_{1})$ = 1.10 $\pm$ 0.10 - equivalent to $E(B-V)$ = 0.55 $\pm$ 0.05 - and $T_{1}-M_{T_{1}}$ = 13.45 $\pm$ 0.25 for log {\it t} = 8.80 and $Z$ = 0.008. NGC\,2236 is then located at 2.5 $\pm$ 0.5 kpc from the Sun beyond the Perseus spiral arm. A cluster core radius of 1.2 pc and an annular corona of 2.2 pc were derived from the stellar density radial profile. A metal abundance [Fe/H] = -0.3 $\pm$ 0.2 was estimated from five independent Washington abundance indices, which is in reasonable agreement with the one obtained from the isochrone fit as well as being compatible with the existence of a radial abundance gradient in the Galactic disc. The properties of a sample of 20 known open clusters aligned along the line-of-sight to NGC\,2236 are examined. Berkeley\,27 is the farthest and oldest cluster of this sample