INVESTIGADORES
AHUMADA Andrea Veronica
artículos
Título:
Improvements on the fundamental parameters of the open cluster Tombaugh 1 through Washington system photometry
Autor/es:
PIATTI, A. E.; CLARIÁ, J. J.; AHUMADA, A. V.
Revista:
ASTRONOMY AND ASTROPHYSICS
Editorial:
EDP SCIENCES S A
Referencias:
Lugar: Paris; Año: 2004 vol. 421 p. 991 - 999
ISSN:
0004-6361
Resumen:
We present CCD photometry in the Washington system C and T1
passbands down to T1 ? 18.5 mag in the field of
Tombaugh 1, a little studied open cluster located in the third Galactic
quadrant. We measured T1 magnitudes and C-T1
colours for a total of 1351 stars distributed throughout an area of 13.6
arcmin × 13.6 arcmin. A cluster radius of 4.3 arcmin ± 0.3
arcmin was estimated from star counts in 100-pixel a side boxes
distributed throughout the entire observed field. Based on the best fits
of isochrones computed by the Geneva group for Z = 0.008 to the
T1 vs. C-T1 colour-magnitude diagram, we derive a
colour excess E(C-T1) = 0.55 ± 0.10, equivalent to
E(B-V) = 0.30 ± 0.05, a distance of (2.2 ± 0.5) kpc from
the Sun and an age of 1.3 +0.1-0.2 Gyr. The latter
value is in good agreement with that derived from the independent
metallicity δT1 index defined in Geisler et al. (1997,
AJ, 114, 1920). An independent metallicity estimation using the
[MT_1, (C-T1)0] plane with the standard
giant branches of Geisler & Sarajedini (1999, AJ, 117, 308) yields
[Fe/H] = -0.30 ± 0.25 dex, a value which lends support to the one
obtained from the isochrone fit. Tombaugh 1 is then found to be a
relatively metal-poor intermediate-age open cluster.