CCD BVI Photometry of the Southern Open Clusters Pismis 23 and BH 222

CLARIA OLMEDO, JUAN JOSÉ; PIATTI, ANDRÉS E.

ASTROPHYSICS AND SPACE SCIENCE

Año: 2004 vol. 290 p. 353 - 362

0004-640X

CCD BVI Johnson Cousins photometry of the open cluster candidates Pismis 23 and BH 222 is presented. Both the analysis of the colour-magnitude diagrams and star counts performed in the regions of these two objects support their physical reality. For Pismis 23 we derive E(B‑V) = 2.0 ± 0.1, E(V‑I) = 2.6 ± 0.1, a distance from the Sun d= (2.6 ± 0.6) kpc and an age of (300 ± 100) Myr, while for BH 222 we obtain E(V‑I) = 2. 4 ± 0.2, d= (6.0 ± 2.7) kpc and (60 ± 30) Myr. Both objects, located beyond the Sagittarius arm, are among the most reddened and distant open clusters known in the direction towards the Galactic centre.