vbyCaHbeta CCD Photometry of Clusters. VIII. The Super-Metal Rich, Old Open Cluster NGC 6791
| dc.creator | Anthony-Twarog, B. J. | |
| dc.creator | Twarog, B. A. | |
| dc.creator | Mayer, L. | |
| dc.date | 2006-12-19 | |
| dc.date.accessioned | 2026-07-07T11:20:52Z | |
| dc.date.available | 2026-07-07T11:20:52Z | |
| dc.description | CCD photometry on the intermediate-band vbyCaHbeta system is presented for the metal-rich, old open cluster, NGC 6791. Preliminary analysis led to [Fe/H] above +0.4 with an anomalously high reddening and an age below 5 Gyr. A revised calibration between (b-y)_0 and [Fe/H] at a given temperature shows that the traditional color-metallicity relations underestimate the color of the turnoff stars at high metallicity. With the revised relation, the metallicity from hk and the reddening for NGC 6791 become [Fe/H] = +0.45 +/- 0.04 and E(b-y) = 0.113 +/- 0.012 or E(B-V) = 0.155 +/- 0.016. Using the same technique, reanalysis of the photometry for NGC 6253 produces [Fe/H] = +0.58 +/-0.04 and E(b-y) = 0.120 +/- 0.018 or E(B-V) = 0.160 +/- 0.025. The errors quoted include both the internal and external errors. For NGC 6791, the metallicity from m_1 is a factor of two below that from hk, a result that may be coupled to the consistently low metal abundance from DDO photometry of the cluster and the C-deficiency found from high dispersion spectroscopy. E(B-V) is the same value predicted from Galactic reddening maps. With E(B-V) = 0.15 and [Fe/H] = +0.45, the available isochrones predict an age of 7.0 +/- 1.0 Gyr and an apparent modulus of (m-M) = 13.60 +/- 0.15, with the dominant source of the uncertainty arising from inconsistencies among the isochrones. The reanalysis of NGC 6253 with the revised lower reddening confirms that on both the hk and m_1 metallicity scales, NGC 6253, while less than half the age of NGC 6791, remains at least as metal-rich as NGC 6791, if not richer. | |
| dc.description | Accepted for Astronomical Journal. 42 p. latex file includes 11 figures and 3 tables, one of which is a short version of a data table to appear in online AJ in its entirety | |
| dc.identifier | https://arxiv.org/abs/astro-ph/0612549 | |
| dc.identifier | http://arxiv.org/abs/astro-ph/0612549 | |
| dc.identifier | Astron.J.133:1585-1598,2007 | |
| dc.identifier | doi:10.1086/511976 | |
| dc.identifier.uri | http://salesiana.dossiersoluciones.com/handle/123456789/194098 | |
| dc.subject | Astrophysics | |
| dc.title | vbyCaHbeta CCD Photometry of Clusters. VIII. The Super-Metal Rich, Old Open Cluster NGC 6791 | |
| dc.type | text |