NGC 2401: A TEMPLATE OF CYGNUS ARM YOUNG POPULATION OVER THE THIRD GALACTIC QUADRANT

G. BAUME; A. MOITINHO; R.A. V¨¢ZQUEZ; G. SOLIVELLA; G. CARRARO; S. VILLANOVA

Puc¨®n (Chile)

Congreso; XI Reunión Regional Latinoamericana de Astronomía; 2006

Based on a deep CCD (UBV(RI) [C]) photometric survey and Two-Micron All-Sky-Survey (2MASS) photometry data we derived the main parameters of the open cluster NGC 2401. We found this cluster is located at 6.3 +/- 0.5 kpc (V_0 - M_V = 14.0+/-0.2) from the Sun and is 25 Myr old. That allows us to identify NGC 2401 as a member of the young population belonging to the extension of the Norma - Cygnus spiral- arm over the Third Galactic Quadrant. We additionally constructed the cluster luminosity function down to V ¡Ö 22 and also the cluster initial mass function for all stars with masses above M ¡Ö 1-2 M_V in which case we found a slope x ¡Ö 1.8+/-0.2. A spectroscopic study of the emission star LSS 440 that lies is the cluster area revealed it is a B0Ve star. Its parameters and probable connection with NGC 2401 are also discussed.