EDP Sciences
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Volume 399, Number 2, February IV 2003
Page(s) 543 - 551
Section Stellar clusters and associations
DOI http://dx.doi.org/10.1051/0004-6361:20021828

A&A 399, 543-551 (2003)
DOI: 10.1051/0004-6361:20021828

Multicolour photometry and Coravel observations of stars in the southern open cluster IC 2488

J. J. Clariá1, A. E. Piatti2, E. Lapasset1 and J.-C. Mermilliod3

1  Observatorio Astronómico, Universidad Nacional de Córdoba, Laprida 854, 5000 Córdoba, Argentina
    e-mail: claria@mail.oac.uncor.edu;lapasset@mail.oac.uncor.edu
2  Instituto de Astronomía y Física del Espacio, CC 67, Suc. 28, 1428 Buenos Aires, Argentina
    e-mail: andres@iafe.uba.ar
3  Institut d'Astronomie de l'Université de Lausanne, 1290 Chavannes-des-Bois, Switzerland
    e-mail: Jean-Claude.Mermilliod@obs.unige.ch

(Received 3 October 2002 / Accepted 10 December 2002 )

We present new UBV photoelectric observations of 119 stars in the field of the southern open cluster IC 2488, supplemented by DDO and Washington photometry and Coravel radial velocities for a sample of red giant candidates. Nearly 50% of the stars sampled - including three red giants and one blue straggler - are found to be probable cluster members. Photometric membership probabilities of the red giant candidates show good agreement with those obtained from Coravel data. A mean radial velocity of (-2.63 $\pm$ 0.06) km s -1 is derived for the cluster giants. The reddening across the cluster is found to be uniform, the mean value being E(B-V) = 0.24 $\pm$ 0.04. IC 2488, located at a distance of (1250 $\pm$ 120) pc from the Sun and 96 pc below the Galactic plane, is most probably not related to the planetary nebula ESO 166-PN21. A metal abundance [Fe/H] = 0.10 $\pm$ 0.06 relative to the Sun is determined from DDO data of the red giant members, in good agreement with the [Fe/H] values derived from five independent Washington abundance indices. An age of 180 Myr is determined from the fitting of isochrones computed with convective overshooting for Z = 0.019. The isochrone for log t = 8.25 reproduces remarkably well not only the morphology of the upper main sequence but also the observed red giant pattern.

Key words: methods: observational -- open clusters and associations: individual: IC2488 -- star: abundances -- stars: Hertzsprung-Russell (HR) diagram and C-M diagrams

Offprint request: J. J. Clariá, claria@mail.oac.uncor.edu

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