The SSPs DataBase
The SSPs are based on the new release by Girardi (2003, private communication)
of the Padova Library of stellar models and companion isochrones. The details
are described in Salasnich
et al. (2000) and Girardi
et al. (2000) (see also the Padova
Isochrones DataBase)
Suffice it to mention that: (i) the stellar models extend from the ZAMS up to either the start of the TP-AGB phase or carbon ignition; (ii) in low mass stars passing from the tip of red giant branch (T-RGB) to the HB or clump, mass-loss by stellar winds is included according to the Reimers (1975) rate with h=0.45; (iii) the whole TP-AGB phase is included in isochrones older than 0.1 Gyr according to the algoritm of Girardi & Bertelli (1998) and the mass-loss rate of Vassiliadis & Wood (1993).
SSPs are presented for six different prescriptions for the IMF : four power-lows (Salpeter 1955, Arimoto & Yoshii 1987, Kennicutt 1983, and Kroupa 1998) and three exponential-laws (Larson 1998, for solar neighbourhood and steeper, and Chabrier 2001).
The initial metallicity (Z) of the stellar models range from 0.0001 to 0.100, whereas the initial helium content goes from 0.23 to 0.455 according to the enrichment law DY/DZ=2.25:
| Z |
0.0001 |
0.0004 |
0.001 |
0.004 |
0.008 |
0.019 |
0.040 |
0.070 |
|
| Y |
0.230 |
0.230 |
0.230 |
0.240 |
0.250 | 0.273 |
0.320 |
0.390 |
0.455 |
| X |
0.770 |
0.770 |
0.769 |
0.756 |
0.742 |
0.708 |
0.640 |
0.540 |
0.445 |
The Spectral Energy Distribution
of each SSPs has been computed adopting the library of stellar spectra
assembled by
Girardi et al. (2002).
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Last update: Set 26, 2007