IAFE   05512
INSTITUTO DE ASTRONOMIA Y FISICA DEL ESPACIO
Unidad Ejecutora - UE
artículos
Título:
RUPRECHT\,1: A VERY SMALL, MODERATELY YOUNG OPEN CLUSTER IN THE THIRD GALACTIC QUADRANT
Autor/es:
PIATTI, ANDRÉS E.; CLARIA OLMEDO, JUAN JOSÉ; PARISI, M.C.; AHUMADA, A.V.
Revista:
Baltic Astronomy
Referencias:
Año: 2008 vol. 17 p. 67 - 77
Resumen:
We present $CCD$ observations in the {it Washington} system $C$ and $T_1$ passbands down to $T_1$ $sim$ 18.5 in the field of Ruprecht,1, a poorly studied open cluster located in the third Galactic quadrant. We measured $T_1$ magnitudes and $C-T_1$ colors for a total of 862 stars distributed throughout an area of 13.6´ x 13.6´. The cluster turned out to be very small, its linear radius being 2.6 $pm$ 0.2 pc, as estimated from star counts in appropriate-sized boxes distributed throughout the entire field observed. By fitting the zero-age main sequence  to the ($T_1$,$C-T_1$) color-magnitude diagram, we derive $E_{B-V}$ = 0.25 $pm$ 0.05, independently from the cluster´s metallicity. Our analysis suggests that Ruprecht,1 is moderately young. In fact, adopting the theoretical metal contents $Z$ = 0.02 and 0.008, which provide the best global fits, we derive heliocentric distances of $d$ = 1.9 $pm$ 0.4 kpc and 1.5 $pm$ 0.3 kpc and ages of 200 $pm$ 47 Myr and 251 $pm$ 58 Myr in each case.