Show simple item record

dc.contributor.authorAnthony-Twarog, Barbara
dc.contributor.authorDeliyannis, Constantine P.
dc.contributor.authorTwarog, Bruce A.
dc.identifier.citationAnthony-Twarog, Barbara J., Constantine P. Deliyannis, and Bruce A. Twarog. "A UvbyCa Hβ ANALYSIS OF THE OLD OPEN CLUSTER, NGC 6819." The Astronomical Journal 148.3 (2014): 51.
dc.descriptionThis is the published version. Copyright © 2014. The American Astronomical Society. All rights reserved.en_US
dc.description.abstractNGC 6819 is a richly populated, older open cluster situated within the Kepler field. A CCD survey of the cluster on the uvbyCaHβ system, coupled with proper-motion membership, has been used to isolate 382 highly probable, single-star unevolved main-sequence members over a 20' field centered on the cluster. From 278 F dwarfs with high precision photometry in all indices, a mean reddening of E(b – y) = 0.117 ± 0.005 or E(B – V) = 0.160 ± 0.007 is derived, where the standard errors of the mean include both internal errors and the photometric zero-point uncertainty. With the reddening fixed, the metallicity derived from the same 278 stars is [Fe/H] = –0.116 ± 0.101 from m 1 and –0.055 ± 0.033 from hk, for a weighted average of [Fe/H] = –0.06 ± 0.04, where the quoted standard errors of the mean include the internal errors from the photometric scatter plus the uncertainty in the photometric zero points. If metallicity is derived using individual reddening values for each star to account for potential reddening variation across the face of the cluster, the analogous result is unchanged. The cluster members at the turnoff of the color-magnitude diagram are used to test and confirm the recently discovered variation in reddening across the face of the cluster, with a probable range in the variation of ΔE(B – V) = 0.045 ± 0.015. With the slightly higher reddening and lower [Fe/H] compared to commonly adopted values, isochrone fitting leads to an age of 2.3 ± 0.2 Gyr for an apparent modulus of (m – M) = 12.40 ± 0.12.en_US
dc.publisherAmerican Astronomical Societyen_US
kusw.kuauthorAnthony-Twarog, Barbara
kusw.kuauthorTwarog, Bruce A.
kusw.kudepartmentPhysics and Astronomyen_US
kusw.oanotesPer SHERPA/RoMEO, 12/18/15: Author's Pre-print: green tick author can archive pre-print (ie pre-refereeing) Author's Post-print: green tick author can archive post-print (ie final draft post-refereeing) Publisher's Version/PDF: green tick author can archive publisher's version/PDF General Conditions:

On any website or open access repository Publisher copyright and source must be acknowledged Must link to publisher version Publisher's version/PDF may be used
kusw.oaversionScholarly/refereed, publisher version
kusw.oapolicyThis item meets KU Open Access policy criteria.

Files in this item


This item appears in the following Collection(s)

Show simple item record