NGC 5288: an open cluster with a low-density extended coronal region located beyond the Carina spiral arm

A.E. PIATTI, J.J. CLARI Y A.V. AHUMADA

Capilla del Monte, Córdoba

Congreso; 49 Reunión Anual de la asociación Argentina de Astronomía; 2006

Observatorio Astronómico de la Univ. Nac. de Córdoba

We present CCD BVI images of 15688 stars in the field of thepreviously unstudied open cluster NGC5288. The cluster has an angular core of  ~1.3´ and a low-density extended coronal region of ~ 6.3´. Using theoretical isochrones and adopting Z = 0.040, which provides the best global fit, we derive an age of (130 ± 35) Myr, E(B-V) = 0.75, E(V-I) =0.95 and V-MV = 14.00. The cluster is located at (2.1 ± 0.3) kpc fromthe Sun beyond the Carina spiral arm. Using CCD VI data publishedfor the open cluster NGC 5381, its fundamental parameters are derivedfor the first time. The properties of some open clusters aligned along theline-of-sight of NGC 5288 and others of similar ages to NGC 5288 areexamined. Evidence is presented that the latter ones did not form mainlyalong the spiral arms but rather in the thin disc (Z  ~ ± 100 pc).