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The anticentre old open cluster NGC 1883: radial velocity and metallicity
Having already reported on the first photometric study of theintermediate-age open cluster NGC 1883, in this paper we present thefirst spectroscopic multi-epoch investigation of a sample of evolvedstars in the same cluster. The aim is to derive the cluster membership,velocity and metallicity, and to discuss recent claims in the literaturethat NGC1883 is as metal-poor as globular clusters in the halo. Besides,as it is one of the few outer Galactic disc intermediate-age openclusters known so far, it is an ideal target to improve our knowledge ofthe Galactic disc radial abundance gradient, which is a basic ingredientfor any chemical evolution model of the Milky Way. The new data we haveobtained allow us to make the basic parameters of NGC1883 more reliable.We find that the cluster has a mean metallicity of [Fe/H] = -0.20 +/-0.22, from which we infer an age (650+70-70 Myr)close to that of Hyades and a Galactocentric distance of12.3+0.4-0.2 kpc. The metal abundance, kinematicsand position make NGC1883 a genuine outer disc intermediate-age opencluster. We confirm that in the outer Galactic disc the abundancegradient is shallower than in the solar vicinity.
| A deep focus on NGC 1883
A deep photometric analysis in the open star cluster NGC 1883 has beenpresented here and added to the work of Carraro et al. (2003), which isthe only previous work introduced for this cluster. The radius andmetallicity have been re-estimated in the present work. In addition, newparameters, namely luminosity function, mass function, total mass, masssegregation and the relaxation time of the cluster NGC 1883 have beenestimated here for the first time.
| NGC 1883: a neglected intermediate-age open cluster located in the outskirts of the Galactic disc
We report on BVI CCD photometry of a field centred in the region of theopen cluster NGC 1883, down to V= 21. This cluster has never beenstudied so far; we provide, for the first time, estimates of itsfundamental parameters - namely radial extent, age, distance andreddening. We find that the cluster has a radius of about 2.5 arcmin,and shows signatures of dynamical relaxation. NGC 1883 is located in theanticentre direction, and exhibits a reddening in the range E(B-V) =0.23-0.35, depending on the metal abundance. It turns out to be ofintermediate age (1 Gyr old), and is quite distant for an open cluster.In fact, it is located 4.8 kpc from the Sun, and more than 13 kpc fromthe Galactic centre. This results makes NGC 1883 one of the mostperipheral old open clusters, with important consequences for the trendof the metallicity with distance in the outer Galactic disc.
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