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ABSTRACT: We present a detailed spectroscopic study of a sample of 34 star-forming dwarf galaxies, ranging from the blue to near-infrared (λ3700Å-1μm) (Kehrig et al. 2006). The metal enrichment in this kind of objects has been operating typically at low metallicity enviroments. The spectra were observed with the 1.52m telescope at La Silla/ESO. We derive fundamental parameters for HII regions and ionizing sources in our star-forming galaxies, as well as gaseous metal abundances. All the spectra include the nebular[SIII]λλ9069,9532Å lines, that are of crucial importance in the derivation of the S/H abundances, and relevant ionization diagnostics. We study the relative hardness of their ionizing sources using the η' parameter (Vílchez & Pagel 1988), and exploring the roles played by metallicity and age. The ionic and total O/H was also derived using direct determinations of the te[OIII]. The mean S/O ratio derived in this work is constant and slightly below the solar (S/O) value (see fig 1). The data presented here are consistent with the conclusion that S/O remains constant as O/H varies among the sample of HII galaxies. Variations in S/O along the whole O/H abundance range may be present, but the scatter in S/O (due mainly to observational errors) is still large to constrain them. The assumption that the S/O ratio remains constant for all abundances is still an open question and should be explored further (Pérez-Montero et al. 2006).
Proceedings of the International Astronomical Union 07/2006; 2:315 - 315.
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ABSTRACT: A detailed spectroscopic study, from lambda 3700 A to 1 um, was performed for a sample of 34 HII galaxies in order to derive fundamental parameters for their HII regions and ionizing sources, as well as gaseous metal abundances. All the spectra included the nebular [SIII]9069,9532 A lines, given their importance in the derivation of the S/H abundance and relevant ionization diagnostics. A systematic method was followed to correct the near-IR [SIII] line fluxes for the effects of the atmospheric transmission.A comparative analysis of the predictions of the empirical abundance indicators R23 and S23 has been performed. The relative hardness of their ionizing sources was studied using the eta parameter, and exploring the role played by metallicity. For 22 galaxies of the sample a direct value of te[SIII] was derived, along with their ionic and total S/H abundances. Their ionic and total O/H abundances were derived using direct determinations of te[OIII].For the rest of the objects, the total S/H abundance was derived using S23. The abundance range covered by our sample goes from 1/20 solar up to solar metallicity. The mean S/O ratio derived is log (S/O)=-1.68+/-0.20 dex, 1 sigma below the solar S/O value. The S/O abundance ratio shows no significant trend with O/H over the range of abundance covered in this work, in agreement with previous findings.There is a trend for HII galaxies with lower gaseous metallicity to present harder ionizing spectra. We compared the distribution of the ionic ratios O+/O++ vs. S+/S++ derived for our sample with the predictions of a grid of photoionization models performed for different stellar effective temperatures. This analysis indicates that a large fraction of galaxies in our sample seem to be ionized by extremely hard spectra. Comment: 12 pages, 8 figures, accepted for publication in the A&A, minor gramatical corrections included
06/2006;
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ABSTRACT: In this paper, we investigate the behaviour of the number of Lyman continuum ionizing photons as compared to the actual number of hydrogen recombinations in HII galaxies. We evaluate the number of ionizing photons from the population synthesis of spectra observed in the visible, extrapolating the spectra to the extreme ultraviolet (EUV), beyond the Lyman limit. We check for possible systematic deviations of the predicted ionizing spectra in the EUV by comparing the ratio of the predicted number of ionizing photons to the number of recombinations, as measured in H$\beta$, ${\rm \Delta \log Q(H^0)}$, with the metallicity. We find that, as far as the number of ionizing photons is concerned, no systematic tendency can be detected. The ${\rm H\beta}$ equivalent width can be understood as a nebular age indicator, decreasing with age, although the observed ${\rm H\beta}$ equivalent width can also be affected by the contribution to the continuum by the accumulation of previous, non-ionizing stellar populations. We attribute the increase of ${\rm \Delta \log Q(H^0)}$ with the age of the burst to the fact that more and more ionizing photons escape the nebulae when the nebulae get older, because of their increasing, expansion-induced subfragmentation. Comment: 14 pages, accepted in A&A
05/2006;
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[hide abstract]
ABSTRACT: We have analysed long-slit spectrophotometric observations of a sample
of 35 H II galaxies in the red (between 6000Å and 1 μm),
including the nebular [S III] λλ9069,9532Å lines.
For 6 of the 35 objects observed it has been possible to measure the
auroral [S III] line at 6312Å. All of these galaxies were observed
previously in the blue, and it has therefore been possible to derive two
line temperatures directly: t([O III]) from the [O III]
λ4363Å line and t([S III]) from the [S III]
λ6312Å line. Both spectra, red and blue, were obtained on
the 1.52m telescope with the Boller & Chivens spectrograph at La
Silla, ESO. In this work, we present the physical conditions and
chemical abundances of these 6 galaxies derived from the measured [S
III]λ6312Å line, with particular emphasis on the S/H
abundance. Despite the observed dispersion in the temperatures, the
final result for the abundances is in accordance with the expected
values for H II galaxies. In addition, we have added our observed H II
galaxies to the empirical calibration of
the metallicity parameter, S23 = ([S II]+[S III])/Hα
(Pérez-Montero & Díaz 2003). This calibration presents
two important advantages with respect to the R23 parameter,
which is based on the optical oxygen lines: it remains single-valued up
to abundances close to solar and is almost independent of the ionization
parameters of the nebula.
04/2005; 329:32P.
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ABSTRACT: We analyse the stellar content of a large number of HII galaxies from the continua and absorption features of their spectra using population synthesis methods, in order to gain information about the star formation histories of these objects. We find that all galaxies of our sample contain an old stellar population (>= 1 Gyr) that dominates the stellar mass, and in a majority of these we also found evidence for an intermediate-age population >= 50 Myr apart from the presently bursting, ionizing young generation <= 10^7 yrs Comment: 23 pages, 14 Encapsulated Postscript figures, accepted for publication in A&A
05/2004;
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[hide abstract]
ABSTRACT: We present a sample of 9 nearby F-type stars with detailed spectroscopic
analyses to investigate the Basel Stellar Library (BaSeL) in two
photometric systems simultaneously, Johnson UBV and Strömgren uvby.
The sample corresponds to potential targets of the central seismology
programme of the COROT (COnvection & ROtation) space experiment,
which have been recently observed at Observatoire de Haute-Provence
(OHP, France). The atmospheric parameters Teff, [Fe/H], and
log g obtained from the BaSeL models are compared with spectroscopic
determinations as well as with results of other photometric calibrations
(the TEMPLOGG method and the catalogue of Marsakov & Shevelev,
1995). Moreover, new rotational velocity determinations are also derived
from the spectroscopic analysis and compared with previous results
compiled in the SIMBAD database. For a careful interpretation of the
BaSeL solutions, we computed confidence regions around the best
χ2-estimates and projected them on
Teff-[Fe/H], Teff-log g, and log g-[Fe/H]
diagrams. In order to simultaneously and accurately determine the
stellar parameters Teff, [Fe/H] and log g, we suggest to use
the combination of the synthetic BaSeL indices B-V, U-B and b-y (rather
than the full photometric information available for these stars: B-V,
U-B, b-y, m1 and c1) and we present complete
results in 3 different diagrams, along with the results of other methods
(photometric and spectroscopic). All the methods presented give
consistent solutions, and the agreement between TEMPLOGG and BaSeL for
the hottest stars of the sample could be especially useful in view of
the well-known difficulty of spectroscopic determinations for fast
rotating stars. Finally, we present current and future developments of
the BaSeL models for a systematic application to all the COROT targets.
Journal of Astronomical Data. 11/2001; 7:8.
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ABSTRACT: Double-lined spectroscopic binaries which are also eclipsing provide the most accurate stellar data, and are consequently of first importance to improve stellar evolution modelling. While the mass and radius of each component of detached eclipsing binaries (EBs) can be accurately known, their temperature Teff and chemical composition ([Fe/H]) are still uncertain. To contribute to overcome these difficulties, we present metallicity-dependent Teff determinations of 11 EBs (22 individual stars) from Stromgren synthetic photometry. Inconsistencies suggesting new photometric observations are discussed. Moreover, by exploring the best chi^2-fits to the photometric data, we have re-derived their reddening.
11/2001;
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ABSTRACT: We discuss the possibilities of the BaSeL models in its lowest temperature boundary (Teff ~ 2500 K for cool giants) to provide the Teff of AGB stars. We present the first step of our work, by comparing our predictions for the AGB star R Fornacis with the results of Lorenz-Martins & Lefevre (1994) based on the dust spectral energy distribution.
11/2001;
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ABSTRACT: COROT and GAIA are two future major space missions directly connected to most of the stellar astrophysic questions, from stellar physics to evolution of galaxies. We describe a project for the preparation of these two missions by using the possibilities of the ``BaSeL'' models, a library of theoretical stellar energy distributions, to provide automatically the fundamental stellar parameters of the candidate stars. We present the results already obtained for the stars of the COROT main programme.
11/2001;
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[show abstract]
[hide abstract]
ABSTRACT: We extend the colour calibration of the widely used BaSeL standard stellar library (Lejeune, Cuisinier, & Buser 1997, 1998) to non-solar metallicities, down to [Fe/H] ~ -2.0 dex. Surprisingly, we find that at the present epoch it is virtually impossible to establish a unique calibration of UBVRIJHKL colours in terms of stellar metallicity [Fe/H] which is consistent simultaneously with both colour-temperature relations and colour-absolute magnitude diagrams (CMDs) based on observed globular cluster photometry data and on published, currently popular standard stellar evolutionary tracks and isochrones. The problem appears to be related to the long-standing incompleteness in our understanding of convection in late-type stellar evolution, but is also due to a serious lack of relevant observational calibration data that would help resolve, or at least further significant progress towards resolving this issue. In view of the most important applications of the BaSeL library, we here propose two different metallicity calibration versions: (1) the "WLBC 99" library, which consistently matches empirical colour-temperature relations and which, therefore, should make an ideal tool for the study of individual stars; and (2), the "PADOVA 2000" library, which provides isochrones from the Padova 2000 grid (Girardi et al., 2000) that successfully reproduce Galactic globular-cluster colour-absolute magnitude diagrams and which thus should prove particularly useful for studies of collective phenomena in stellar populations in clusters and galaxies. Comment: 15 pages, LaTeX, documentclass aa, accepted for A and A
10/2001;
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[show abstract]
[hide abstract]
ABSTRACT: We present a sample of 9 nearby F-type stars with detailed spectroscopic analyses to investigate the Basel Stellar Library (BaSeL) in two photometric systems simultaneously, UBV Johnson and uvby Stromgren. The sample corresponds to potential targets of the central seismology programme of the COROT space experiment, which have been recently observed at Observatoire de Haute-Provence (OHP, France). The atmospheric parameters Teff, [Fe/H], and log g obtained from the BaSeL models are compared with spectroscopic determinations as well as with results of other photometric calibrations. Moreover, new rotational velocity determinations are also derived from the spectroscopic analysis and compared with previous results compiled in the SIMBAD database. All the methods presented give consistent solutions, and the agreement between Templogg and BaSeL for the hottest stars of the sample could be especially useful in view of the well known difficulty of spectroscopic determinations for fast rotating stars. Finally, we present current and future developments of the BaSeL models for a systematic application to all the COROT targets. (Abridged)
08/2001;
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[show abstract]
[hide abstract]
ABSTRACT: The Basel Stellar Library (BaSeL models) is constituted of the merging of various synthetic stellar spectra libraries, with the purpose of giving the most comprehensive coverage of stellar parameters. It has been corrected for systematic deviations detected in respect to UBVRIJHKLM photometry at solar metallicity, and can then be considered as the state-of-the-art knowledge of the broad band content of stellar spectra. In this paper, we consider a sample of 9 F-type stars with detailed spectroscopic analysis to investigate the Basel Stellar Library in two photometric systems simultaneously, Johnson (B-V, U-B) and Stromgren (b-y, m_1, and c_1). The sample corresponds to potential targets of the central seismology programme of the COROT space experiment, which have been recently observed at OHP. The atmospheric parameters T_eff, [Fe/H], and log g obtained from the BaSeL models are compared with spectroscopic determinations as well as with results of other photometric calibrations. For a careful interpretation of the BaSeL solutions, we computed confidence regions around the best $\chi$^2-estimates and projected them on T_eff-[Fe/H], T_eff-log g, and log g-[Fe/H] diagrams. (Abridged)
05/2000;
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[hide abstract]
ABSTRACT: A standard library of theoretical stellar spectra intended for multiple
synthetic photometry applications including spectral evolutionary
synthesis is presented. The grid includes M dwarf model spectra, hence
complementing the first library version established in Paper I (Lejeune
et al., 1997, Cat. <J/A+AS/125/229>). It covers the following wide
ranges of fundamental parameters: Teff: 50,000 to 2000K, logg: 5.5 to
-1.02, and [Fe/H]: +1.0 to -5.0. A correction procedure is also applied
to the theoretical spectra in order to provide color-calibrated flux
distributions over a large domain of effective temperatures. Empirical
Teff-color calibrations are constructed between 11500K and 2000K, and
semi-empirical calibrations for non-solar abundances ([Fe/H]=-3.5 to
+1.0) are established. Model colors and bolometric corrections for both
the original and the corrected spectra, synthesized in the
UBV(RI)c(JHKLL'M) system, are given for the full range of stellar
parameters. Synthetic colors: ---------------- Synthetic UBV(RI)c(JHKLM)
colors have been computed from both the original and the corrected model
flux distributions presented in Paper I (1997A&AS..125..229L; see
catalog <J/A+AS/125/229>), as the files lcb98ori.dat and
lcb98cor.dat respectively; the results are also presented in individual
files lcb98xxx.ori and lcb98xxx.cor, where xxx designates the
metallicity (ex: 'm15' --> [Fe/H]=-1.5). For each file, we give
synthetic colors computed from energy-weighted and photon-weighted
stellar fluxes. Semi-empirical calibrations: ---------------------------
Empirical ([Fe/H]=0.0) and semi-empirical (-3.5<=[Fe/H]<=+1.0)
Teff-colors (UBVRIJHKLM) calibrations are given in Tables 1 to 10. (51
data files).
VizieR Online Data Catalog. 05/1998; 413:00065.
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[hide abstract]
ABSTRACT: The present library provides an extensive and homogeneous grid of
low-resolution theoretical flux distributions for a large range of
stellar parameters : Teff=50,000K to K, logg=5.50 to -1.02 and
[M/H]=-5.0 to +1.0. The library has been constructed from different
grids of blanketed stellar atmosphere models (Bessell et al.
(1989A&AS...77....1B, 1991A&AS...89..335B), Fluks et al. (1994,
Cat. <J/A+AS/105/311>), Kurucz (1995, priv. comm.), Allard &
Hauschildt (1995ApJ...445..433A). The models described in the
accompanying paper (Lejeune et al. (1997A&AS..125..229L) are given
here as part of a more extensive data set including M dwarf model
spectra, which will be presented in a forthcoming paper (Lejeune et al.,
1998, Cat. <J/A+AS/130/65>). A correction procedure has been
applied to the theoretical energy in order to calibrate fluxes on
empirical-temperature relations (see also Lejeune et al., 1998, Cat.
<J/A+AS/130/65>). The library is given here in its two versions :
the first one (files *.ori) containing the "original" flux distributions
-- as given by the original grids of atmosphere models --, but rebinned
on a common wavelength scale (see also Leitherer et al.
1996PASP..108..996L) and the second one (files *.cor) which provides the
"corrected" flux distributions. Each version of the library contains an
ASCII file of models for each of the 19 values of the metallicity
([M/H]=-5.0, -4.5, -4.0, -3.5, -3.0, -2.5, -2.0, -1.5, -1.0, -0.5, -0.3,
-0.2, -0.1, 0.0, +0.1, +0.2, +0.3, +0.5 and +1.0), named as lcbxxx.yyy,
where xxx designates the metallicity (ex: 'm15' --> [M/H]=-1.5), and
yyy identifies the library version. For each model (out of the total of
8315 models), a flux spectrum is given for the (same) set of 1221
wavelength points covering the range 9.1 to 160000 nm, with a mean
resolution of 10Å in the UV and 20Å in the visible. In
addition to the 19 metallicity files, two individual files originating
from the Kurucz (1991, in Precision Photometry: Astrophysics of the
Galaxy, Davis Philip A.G., Upgren A.R. & Janes K.A. (eds.).
Schenectady, NY, L. Davis Press, Inc., 1991, pp. 27-44)) models are
given, lcbsun.ori and lcbvega.ori, which provide theoretical flux
distributions for the Sun and Vega respectively. (1 data file).
VizieR Online Data Catalog. 10/1997; 412:50229.
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[show abstract]
[hide abstract]
ABSTRACT: A standard library of theoretical stellar spectra intended for multiple synthetic photometry applications including spectral evolutionary synthesis is presented. The grid includes M dwarf model spectra, hence complementing the first library version established in Paper I (Lejeune, Cuisinier & Buser 1997). It covers wide ranges of fundamental parameters: Teff : 50,000 K to 2000 K, log g : 5.5 to -1.02, and [M/H] : +1.0 to -5.0. A correction procedure is also applied to the theoretical spectra in order to provide color-calibrated flux distributions over a large domain of effective temperatures. For this purpose, empirical Teff-color calibrations are constructed between 11500 K and 2000 K, and semi-empirical calibrations for non-solar abundances ([M/H] = -3.5 to +1.0) are established. Model colors and bolometric corrections for both the original and the corrected spectra, synthesized in the UBVRcIcJHKLL'M system, are given for the full range of stellar parameters. We find that the corrected spectra provide a more realistic representation of empirical stellar colors, though the method employed is not completely adapted to the lowest temperature models. In particular the original differential colors of the grid implied by metallicity and/or luminosity changes are not preserved below 2500 K. Limitations of the correction method used are also discussed. Comment: Accepted for publication in A&A Supplement Series (LaTex); 22 pages, including 8 postscript figures and 10 tables. Also available at http://www.astro.unibas.ch/~lejeune/
10/1997;
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[show abstract]
[hide abstract]
ABSTRACT: We compare observed color-magnitude diagrams (CMDs) of the three
metal-rich bulge globular clusters NGC 6553, NGC 6528 and Terzan 5, and
integrated spectral energy distributions (SEDs) of NGC 6528 and 47 Tuc,
to theoretical isochrones and model SEDs computed with the code of
Bruzual & Charlot (1997, hereafter BC97). The BC97 models provide
the evolution in time of the spectrophotometric properties of simple
stellar populations (SSPs) for a wide range of stellar metallicity.
These models allow us to compare predictions based on different sets of
evolutionary tracks and various choices of the stellar spectral
libraries with observational data. We conclude that: (a) At least for
solar metallicity models, the semi-empirical flux corrections applied by
Lejeune et al. (1997a,b) to available grids of synthetic stellar spectra
improve the agreement between population model predictions and
observations. (b) The adopted reddening and distance moduli for the
three clusters seem well determined, since the theoretical isochrones
fit quite well the observed CMDs. (c) The overall metallicity of these
clusters is close to solar. (d) Based on our CMD and SED models we
estimate that the ages of NGC 6553 and NGC 6528 must be ~ 12 +/- 2 Gyr.
These are the only two clusters in our sample with main sequence
photometry. From the UV-optical SED of 47-Tuc we estimate an age of ~ 14
+/- 2 Gyr.
The Astronomical Journal 09/1997; 114:1531. · 4.03 Impact Factor
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[show abstract]
[hide abstract]
ABSTRACT: A comprehensive hybrid library of synthetic stellar spectra based on three original grids of model atmosphere spectra by Kurucz (1995), Fluks et al. (1994), and Bessell et al. (1989, 1991) is presented. The combined library is intended for multiple-purpose synthetic photometry applications and is constructed in order (i) to cover the largest possible ranges in Teff, log g, and [M/H]), (ii) to provide flux spectra with useful resolution on the uniform grid of wavelengths, and (iii) to provide realistic synthetic broad-band colors for the largest possible parameter and wavelength ranges. For each value of the effective temperature and for each wavelength, we calculate the correction function that must be applied to a (theoretical) solar-abundance model flux spectrum which yields synthetic UBVRIJHKL colors matching the (empirical) color-temperature calibrations derived from observations. The calibration algorithm is designed to preserve the original differential grid properties implied by metallicity and/or luminosity changes in the new library. The corresponding color calibration is described in some detail. Comment: 17 pages, Latex, 19 Figures (postscript), accepted for publication in A&A. Also available with figures as ps-file at http://www.astro.unibas.ch/structure/papers.html
01/1997;
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[show abstract]
[hide abstract]
ABSTRACT: We present a comprehensive hybrid library of synthetic stellar spectra based on three original grids of model atmosphere spectra by Kurucz (1995), Fluks et al. (1994), and Bessell et al. (1989, 1991), respectively. The combined library has been intended for multiple-purpose synthetic photometry applications and was constructed according to the precepts adopted by Buser & Kurucz (1992): (i) to cover the largest possible ranges in stellar parameters ($ T_{\rm eff}$, $\log g$, and $[M/H]$); (ii) to provide flux spectra with useful resolution on the uniform grid of wavelengths adopted by Kurucz (1995); and (iii) to provide synthetic broad–band colors which are highly realistic for the largest possible parameter and wavelength ranges. Because the most astrophysically relevant step consists in establishing a realistic library, the corresponding color calibration is described in some detail. Basically, for each value of the effective temperature and for each wavelength, we calculate the correction function that must be applied to a (theoretical) solar–abundance model flux spectrum in order for this to yield synthetic $UBVRIJHKL$ colors matching the (empirical) color–temperature calibrations derived from observations. In this way, the most important systematic differences existing between the original model spectra and the observations can indeed be eliminated. On the other hand, synthetic $UBV$ and Washington ultraviolet excesses $\delta_{(U-B)}$ and $\delta_{(C-M)}$ and $\delta_{(C-T_{1})}$ obtained from the original giant and dwarf model spectra are in excellent accord with empirical metal–abundance calibrations (Lejeune & Buser 1996). Therefore, the calibration algorithm is designed in such a way as to preserve the original differential grid properties implied by metallicity and/or luminosity changes in the new library, if the above correction function for a solar–abundance model of a given effective temperature is also applied to models of the same temperature but different chemical compositions $[M/H]$ and/or surface gravities $\log g$. While the new library constitutes a first–order approximation to the program set out above, it will be allowed to develop toward the more ambitious goal of matching the full requirements imposed on a standard library . Major input for refinement and completion is expected from the extensive tests now being made in population and evolutionary synthesis studies of the integrated light of globular clusters (Lejeune 1997) and galaxies (Bruzual et al. 1997).
http://dx.doi.org/10.1051/aas:1997373.
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[show abstract]
[hide abstract]
ABSTRACT: A standard library of theoretical stellar spectra intended for multiple synthetic photometry applications including spectral evolutionary synthesis is presented. The grid includes M dwarf model spectra, hence complementing the first library version established in Paper I ([CITE]). It covers wide ranges of fundamental parameters: $T_{\mathrm{eff}}$: 50 000 K ~ 2000 K, $\log g$: 5.5 $\sim -1.02$, and $[M/H]$: $+1.0 \sim -5.0$. A correction procedure is also applied to the theoretical spectra in order to provide color-calibrated flux distributions over a large domain of effective temperatures. For this purpose, empirical $T_{\mathrm{eff}}$–color calibrations are constructed between 11500 K and 2000 K, and semi-empirical calibrations for non-solar abundances ($[M/H]$ $= -3.5$ to +1.0) are established. Model colors and bolometric corrections for both the original and the corrected spectra, synthesized in the $(UBV)_{\rm J}(RI)_{\rm C}JHKLL'M$ system, are given for the full range of stellar parameters. We find that the corrected spectra provide a more realistic representation of empirical stellar colors, though the method employed is not completely adapted to the lowest temperature models. In particular the original differential colors of the grid implied by metallicity and/or luminosity changes are not preserved below 2500 K. Limitations of the correction method used are also discussed.
http://dx.doi.org/10.1051/aas:1998405.
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[show abstract]
[hide abstract]
ABSTRACT: We extend the colour calibration of the widely used BaSeL standard stellar library (Lejeune et al. 1997, 1998) to non-solar metallicities, down to ${\rm [Fe/H]} \sim -2.0$ dex. Surprisingly, we find that at the present epoch it is virtually impossible to establish a unique calibration of $UBVRIJHKL$ colours in terms of stellar metallicity ${\rm [Fe/H]}$ which is consistent simultaneously with both colour-temperature relations and colour-absolute magnitude diagrams (CMDs) based on observed globular cluster photometry data and on published, currently popular standard stellar evolutionary tracks and isochrones. The problem appears to be related to the long-standing incompleteness in our understanding of convection in late-type stellar evolution, but is also due to a serious lack of relevant observational calibration data that would help resolve, or at least further significant progress towards resolving this issue. In view of the most important applications of the BaSeL library, we here propose two different metallicity calibration versions: (1) the “WLBC 99” library, which consistently matches empirical colour-temperature relations and which, therefore, should make an ideal tool for the study of individual stars; and (2), the “PADOVA 2000” library, which provides isochrones from the Padova 2000 grid (Girardi et al. [CITE]) that successfully reproduce Galactic globular-cluster colour-absolute magnitude diagrams and which thus should prove particularly useful for studies of collective phenomena in stellar populations in clusters and galaxies.
http://dx.doi.org/10.1051/0004-6361:20011493.
