INVESTIGADORES
PIATTI Andres Eduardo
congresos y reuniones científicas
Título:
Determinación de parámetros fundamentales de tres cúmulos abiertos a partir de espectroscopía integrada
Autor/es:
AHUMADA, A.V.; CLARIA OLMEDO, JUAN JOSÉ; PIATTI, ANDRÉS E.
Lugar:
La Plata
Reunión:
Congreso; Reunión Anual de la Asoc. Argentina de Astronomía; 1998
Resumen:
Integrated spectroscopy is an observational technique based on the
concept of stellar population sinthesis. Applied in combination with
medium size aperture telescopes (d > 2 m), it enables to infer
fundamental astrophysical properties of compact, faint, and distant
objects. Using this technique, we determine age, interstellar reddening
and metallicity of 3 southern open clusters, namely Hogg 15, Mel 105 and
NGC 2849. The integrated spectra obatined at CASLEO (San Juan,
Argentina) in the spectral range 3500-9200Å with a typical
dispersion of 3.4 Å/pixel, were calibrated in units of wavelength
and flux. A first reddening-independent age was obtained using the
equivalent widths of the Balmer lines. This first estimate allows us to
choise in each case the spectral template whose features most resemble
those of the observed spectra. The interstellar reddening of each
cluster was then varied to get the best match of continuum and spectral
lines. Hogg 15 and NGC 2849 are both very young open clusters with ages
between 3 and 6 million years and E(B-V) colour excesses of 1.05
± 0.03 and 0.53 ± 0.05, respectively. Mel 105 appears to
be much older with an age of nearly 108 years and a reddening
of E(B-V) = 0.31 ± 0.02. Using the near infrared spectral region,
a rough estimate of the metallicity of Hogg 15 and Mel 105 was
determined, but not that of NGC 2849 due to the low signal-to-noise
ratio of the corresponding spectrum. The equivalent widths of spectral
windows including NaI and CaII triplet lines in the infrared allow us to
conclude that Mel 105 and Hogg 15 are metal-rich and metal-poor clusters
as compared to the Sun, respectively.