Open AccessNGC 6404 and 6583: two neglected intermediate‐age open clusters located in the Galactic Centre direction
Author(s) -
Carraro Giovanni,
Méndez René A.,
Costa Edgardo
Publication year - 2005
Publication title -
monthly notices of the royal astronomical society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.058
H-Index - 383
eISSN - 1365-2966
pISSN - 0035-8711
DOI - 10.1111/j.1365-2966.2004.08495.x
Subject(s) - physics , astrophysics , open cluster , photometry (optics) , metallicity , astronomy , disc , star cluster , radius , galaxy , stars , elliptical galaxy , computer security , computer science
We report on VI charge‐coupled device photometry of two fields centred in the region of the open clusters NGC 6404 and 6583 down to V = 22.0 . So far these clusters have never been studied, and we provide for the first time estimates of their fundamental parameters, namely, radial extent, age, distance and reddening. We find that the radius of NGC 6404 is 2.0 arcmin, as previously proposed, while the radius of NGC 6583 is 1.0 arcmin, significantly lower than previous estimates. Both clusters turn out to be of intermediate age (0.5–1.0 Gyr old), and located inside the solar ring, at a Galactocentric distance of about 6.5 kpc. These results make these objects very interesting targets for spectroscopic follow‐up to measure their metallicity. In fact, they might allow us to enlarge by more than 1 kpc the baseline of the radial abundance gradient in the Galactic disc towards the Galactic Centre direction. This baseline is currently rather narrow especially for clusters of this age.