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Astron. Astrophys. 362, 953-958 (2000)

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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

1 Università di Padova, Dept. di Astronomia, Vicolo dell'Osservatorio 5, 35122 Padova, Italy (ortolani, momany@pd.astro.it)
2 Universidade de São Paulo, Dept. de Astronomia, CP 3386, São Paulo 01060-970, Brazil (barbuy@orion.iagusp.usp.br)
3 Universidade Federal do Rio Grande do Sul, Dept. de Astronomia, CP 15051, Porto Alegre 91501-970, Brazil (bica@if.ufrgs.br)
4 University of Virginia, Department of Astronomy, P.O. Box 3818, VA 22903-0818, USA (catelan@virginia.edu)

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) [FORMULA] 0.29 and a distance from the Sun [FORMULA] [FORMULA] 11.2 kpc for NGC 5986, and E(B-V) [FORMULA] 0.33 and [FORMULA] [FORMULA] 7.9 kpc for NGC 6712.

Their galactocentric distances of [FORMULA] = 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 [FORMULA]z[FORMULA] [FORMULA] 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

* Observations collected at the European Southern Observatory - ESO, Chile, proposal no. 64L-0212(A)
** Hubble Fellow

Send offprint requests to: B. Barbuy

© European Southern Observatory (ESO) 2000

Online publication: October 30, 2000