English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Plus annual

Presents the access of premium content as premium feature

Premium Content

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Tools annual

Global: Zendy Free Plan

Global: Zendy Tools monthly

Global: Zendy Plus monthly

We present BVI photometry of the globular cluster NGC 6642 using the SOIimager at the SOAR Telescope. The Colour Magnitude Diagrams (CMD) reach$\approx$1.5mag in V below the main sequence turn-off. A comparison of theoverall sequences, and in particular the Red Giant Branch slope of NGC 6642with that of M~5 indicates that the two clusters must have a similarmetallicity of [Fe/H]$\approx$-1.3. We also obtain for NGC 6642 a reddeningE(B-V)=0.42$\pm$0.03, and a distance from the Sun of d$_{\odot}$=7.2$\pm$0.5kpc. Therefore NGC 6642 is a moderately metal-poor globular cluster, spatiallylocated in the bulge, at a galactocentric distance of R$_{\rm GC}$$\approx$1.7kpc. The comparison of CMDs of NGC 6642 with those of M~5 shows that there is avery good match of magnitude difference between turn-off and horizontal branch,suggesting comparable ages. M~5 has an age typical of the halo globulars, andconsequently NGC 6642 is coeval with the halo. NGC 6642 is a good candidate tobe one of the few genuine metal-poor and old {\it bulge} clusters, and might beone of the most ancient fossils in the Galaxy.Comment: barbuy.tar.gz: 13 pages, 7 figures, includes files aa.cls, psfig.te

SOARBVIphotometry of the metal-poor bulge globular cluster NGC 6642