Volume 390, Number 1, July IV 2002
|Page(s)||59 - 64|
|Section||Cosmology (including clusters of galaxies)|
|Published online||05 July 2002|
New abundance measurements in UKS 1927–177, a very metal-poor galaxy in the Local Group*
European Southern Observatory, Casilla 19001, Santiago 19, Chile
2 Osservatorio Astronomico di Padova, vicolo dell'Osservatorio 5, 35122 Padova, Italy e-mail: (rizzi, held)@pd.astro.it
3 Dipartimento di Astronomia, Università di Padova, vicolo dell'Osservatorio 2, 35122 Padova, Italy e-mail: firstname.lastname@example.org
4 Institute for Astronomy, University of Hawaii, 2680 Woodlawn Drive, Honolulu, HI 96822 e-mail: email@example.com
Corresponding author: I. Saviane, firstname.lastname@example.org
Accepted: 15 May 2002
We present new results from optical spectroscopy of the brightest Hii region in the dwarf irregular galaxy in Sagittarius (SagDIG). From high signal-to-noise spectra, reddening-corrected line flux ratios have been measured with typical uncertainties of a few percent, from which the oxygen abundance is rediscussed, and new abundance estimates are derived for N and Ne. The O abundance in SagDIG, estimated with the empirical abundance indicator and other methods, is in the range to . The fact that SagDIG is 10 times closer than I Zw 18 makes it an ideal target to test the hypothesis of the existence of young galaxies in the present-day universe. Indeed, stellar photometry suggests that this galaxy may harbor a stellar population older than a few Gyr, and possibly an old stellar component as well. The case of SagDIG therefore supports the view that very low chemical abundances can be maintained throughout the life of a dwarf stellar system, even in the presence of multiple star formation episodes.
Key words: galaxies: individual: SagDIG / galaxies: abundances / galaxies: dwarf / galaxies: ISM / galaxies: irregular / Local Group
© ESO, 2002
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