Inci Akkaya,² William J. Schuster,³ Raúl Michel,³ Carlos Chavarría–K,³ André Moitinho,⁴ Roberto Vázquez,³ and Yüksel Karatas⁵

² Department of Astronomy and Space Sciences, Faculty of Arts and Sciences, Erciyes University, Talas Yolu, 38039, Kayseri, Turkey (iakkaya@erciyes.edu.tr).

³ Observatorio Astronómico Nacional, Instituto de Astronomía, Universidad Nacional Autónoma de México, Apdo. Postal 877, 22800 Ensenada, B. C, México (schuster@astrosen.unam.mx, rmm@astrosen.unam.mx, chavarri@astrosen.unam.mx, vazquez@astrosen.unam.mx).

⁴ SIM/IDL, Facultade de Ciencias da Universidade de Lisboa, Ed. C8, Campo Grande, 1749–016, Lisboa, Portugal (andre@sim.ul.pt).

⁵ Istanbul University, Science Faculty, Department of Astronomy and Space Sciences, 34119, Universite–Istanbul, Turkey (karatas@istanbul.edu.tr).

Received 2009 May 15 ]]> Accepted 2010 August 15

RESUMEN

Presentamos los parámetros fundamentales de enrojecimiento, metalicidad, edad y distancia de los cúmulos abiertos poco estudiados Be 89, Ru 135 y Be 10, derivados de la fotometría CCD UBVRI. Los enrojecimientos interestelares se midieron en el diagrama color–color, y las metalicidades fotométricas se derivaron del exceso de ultravioleta de las estrellas tipo F. Las distancias y edades se obtuvieron ajustando isocronas a las secuencias observadas en cinco diagramas color–magnitud diferentes. Los promedios ponderados de los módulos de distancia y distancias heliocéntricas [(V₀ – M_V), d(kpc)] son: (11^m.90 ± 0^m.06, 2.4 ± 0.06) para Be 89, (9^m.58 ± 0^m.07, 0.81 ± 0.03) para Ru 135 y (11^m.16 ± 0^m.06,1.7 ± 0.05) para Be 10, mientras que los promedios ponderados para las edades [log(A), A(Gyr)] son: (9.58 ± 0.06,3.8 ± 0.6) para Be 89, (9.58 ± 0.06,3.8 ± 0.7) para Ru 135 y (9.06 ± 0.05,1.08 ± 0.08) para Be 10.

ABSTRACT

The fundamental parameters of reddening, metallicity, age, and distance are presented for the poorly studied open clusters Be 89, Ru 135, and Be 10, derived from their CCD UBVRI photometry. The interstellar reddenings, E(B–V), were measured in the two–color diagram, and the photometric metallicities, [Fe/H], from the ultraviolet excesses of the F–type stars. By fitting isochrones to the observed sequences of the clusters in five different color–magnitude diagrams, the weighted averages of distance moduli and heliocentric distances [(V₀–M_V), d(kpc)] are (11^m.90 ± 0^m.06,2.4 ± 0.06) for Be 89, (9^m.58 ± 0^m.07,0.81 ± 0.03) for Ru 135, and (11^m.16 ± 0^m.06,1.7 ± 0.05) for Be 10, and the weighted averages of the ages [log(A), A(Gyr)] are (9.58 ± 0.06, 3.8 ± 0.6) for Be 89, (9.58 ± 0.06, 3.8 ± 0.7) for Ru 135, and (9.06 ± 0.05,1.08 ± 0.08) for Be 10.

Key Words: open clusters and associations: individual (Be10, Be89, Ru135) — stars: fundamental parameters — stars: Hertzsprung–Russell and C–M diagrams — techniques: photometric.

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ACKNOWLEDGMENTS

This work was supported by the Conacyt projects 33940, 45014, 49434 and PAPIIT–Universidad Nacional Autónoma de México IN111500 (Mexico). IA acknowledges a grant from the Mexican Government (Secretaría de Relaciones Exteriores). YK acknowledges financial support of the Scientific and Technical Research Council of Turkey (TUBITAK, BIDEB– 2219). This research made use of the WEBDA open cluster database of J.–C. Mermilliod. We also thank an anonymous referee for valuabl

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NOTE

¹ CCD UBVRI Photometry of the Galactic open clusters Based on observations carried out at the San Pedro Mártir National Astronomical Observatory (SPM), operated by Instituto de Astronomía, Universidad Nacional Autónoma de México, Ensenada, B. C, México.