CCD Washington photometry of the moderately metal-poor open cluster NGC 2236

J.J. CLARIÁ, A.E. PIATTI, M.C. PARISI, A.V. AHUMADA

Malargue (Mendoza)

Congreso; 50 Reunión Anual de la Asociación Argentina de Astronomía; 2007

Colaboración Argentina del Observatorio Pierre Auger y el Instituto de Astronomía y Física del Espacio (CONICET/UBA)

CCD CT1 Washington photometry in the field of the open cluster NGC 2236 is presented, together with photoelectric CMT1T2 photometry of 13 red giant candidates. Based on the best fits of isochrones computed for Z = 0.008 to the (T1,C-T1) diagram, we derive E(C-T1) = 1.10 and d = 2.5 kpc for log(age) = 8.80. A metal abundance [Fe/H] = -0.3 +- 0.2 (Z = 0.011) is estimated from five independent abundance indices. We also derive a cluster core radius of  1.2 pc and an annular cluster corona of  2.2 pc. The properties of a sample of 20 known open clusters aligned along the line-of-sight to NGC2236 are examined.