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

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

Malargüe - Argentina

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

CCD CT1 Washington photometry in the .eld of the open cluster NGC 2236 is presented, together with photoelectric CMT1T 2 photometry of 13 red giant candidates. Based on the best fits of isochrones computed for Z = 0.008 to the (T1,C-T 1) diagram, we derive E(C-T 1) = 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 rc = 1.2 pc and an annular cluster corona of Drc = 2.2 pc. The properties of a sample of 20 known open clusters aligned along the line-of-sight to NGC2236 are examined.