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Colour-magnitude diagrams of the inner halo globular clusters NGC 5986 and NGC 6712 *
S. Ortolani 1,
Y. Momany 1,
B. Barbuy 2,
E. Bica 3 and
M. Catelan ** 4
Received 19 July 2000 / Accepted 31 August 2000
We present V and I photometry for NGC 5986 and B and V for NGC 6712. NGC 5986 has a blue extended horizontal branch, while NGC 6712 has a composite red and blue horizontal branch, where the latter extends to unusual bluer colours. Both clusters have RR Lyrae.
We derive a reddening E(B-V) 0.29 and a distance from the Sun 11.2 kpc for NGC 5986, and E(B-V) 0.33 and 7.9 kpc for NGC 6712.
Their galactocentric distances of = 5.2 and 3.6 kpc respectively, locate them in the inner halo; NGC 6712 could be considered to be located in the bulge.
NGC 6712 has z 500 pc, indicating that the cluster is crossing the disk.
We estimate metallicities of [Fe/H] = -1.6 and -1.0 respectively for NGC 5986 and NGC 6712.
Key words: stars: Hertzsprung Russell (HR) and C-M diagrams Galaxy: globular clusters: individual: NGC 5986, NGC 6712
Send offprint requests to: B. Barbuy
Online publication: October 30, 2000