EVOLUTIONARY TRACKS & ISOCHRONES: CANONICAL MODELS

readme file

last modification: 3 Oct 2006


The models do not include gravitational settling, radiative acceleration, convective overshooting, rotational mixing, but otherwise they are based on up-to-date physics, as described in: in Pietrinferni, Cassisi, Salaris & Castelli (2006, ApJ, 642, 797) - in Pietrinferni, Cassisi, Salaris & Castelli (2004, ApJ, 612, 168) - Cassisi, Salaris, Castelli & Pietrinferni (2004, ApJ, 616, 498) - Cassisi, Pietrinferni, Salaris, Castelli, Cordier & Castellani (2005, MmSAI, 77, 71).

We strongly encourage people interested in a specific set of evolutionary tracks (not yet available in this database) to contact us, either by e_mail or by compiling the request form (present in this web site). We'll try to perform these computations within a week upon receiving the request.

We have presently stored evolutionary models with the following chemical compositions:

Z (metallicity)
Y (initial Helium content)
[Fe/H]
[M/H]
0.0001
0.245
-2.62
-2.27
0.0003
0.245
-2.14
-1.79
0.0006
0.246
-1.84
-1.49
0.0010
0.246
-1.62
-1.27
0.0020
0.248
-1.31
-0.96
0.0040
0.251
-1.02
-0.66
0.0080
0.256
-0.70
-0.35
0.0100
0.259
-0.60
-0.25
0.0198
0.273
-0.29
0.06
0.0300
0.288
-0.09
0.26
0.0400
0.303
0.05
0.40

The values Z=0.0198 (zsun) and Y=0.2734 (ysun) correspond to the abundances obtained from the calibration of the solar model (for more details we refer to Pietrinferni et al. 2004).

All models have been computed by using the following alpha enhanced heavy elements distribution:

Element
number fract.
Mass fract.
C12
0.108211
0.076451
N14
0.028462
0.023450
O16
0.714945
0.672836
Ne20
0.071502
0.084869
Na23
0.000652
0.000882
Mg24
0.029125
0.041639
Al27
0.000900
0.001428
Si28
0.021591
0.035669
P30
0.000086
0.000157
S 32
0.010575
0.019942
Cl35
0.000096
0.000201
Ar40
0.001010
0.002373
K39
0.000040
0.000092
Ca40
0.002210
0.005209
Ti48
0.000137
0.000387
Cr52
0.000145
0.000443
Mn55
0.000075
0.000242
Fe56
0.009642
0.031675
Ni59
0.000595
0.002056

All models include mass loss according to the Reimers (1975) law (eta=0.2 and eta=0.4) and the mass range goes from 0.5Mo to 10.0Mo. Please note that the mass spacing is suitably small: we adopt a mass step equal to, respectively, 0.1Mo in the range (0.5 - 2.6) Mo, 0.2Mo between 2.6Mo and 3.0Mo, and 0.5Mo for more massive models.

Each file contains:

in the fifth line - 1) the number of evolutionary points, 2) the global metallicity [M/H], 3) the abundance by mass of metals (Z), 4) the initial He abundance (Y), 5) the inital mass (in solar unit); starting from the ninth line the following quantities are listed:

  1 column) the logarithm of the age in years;
  2 column) the logarithm of the surface luminosity in solar unit;
  3 column) the logarithm of the effective temperature (K);
  4 column) the present mass in solar unit;
  5 column) the visual absolute magnitude;
  6 column) the (B-V) color;
  7 column) the (U-B) color;
  8 column) the (V-I) color;
  9 column) the (V-R) color;
 10 column) the (V-J) color; 
 11 column) the (V-K) color;
 12 column) the (V-L) color; 
 13 column) the (H-K) color; 
from the Zero Age main Sequence until the first few thermal pulses (for masses larger than 0.7Mo).More details about the adopted color-Teff transformations and bolometric correction can be found in the quoted reference.

The coding of the file names is as follows:


 bcdfZlmnYghiaes.nor
      |
      | evolutionary track for a model with --> initial mass = bc.df Mo
                                            --> metallicity Z= l.m x 10^(-n)
                                            --> initial He abundance Y = 0.ghi
                                            --> mixture = alpha enhanced (ae)

The suffix "s" denotes models computed by adopting a Standard evolutionary scenario (no atomic diffusion, no overshooting). The suffix "nor" indicates that the evolutionary sequence has been "reduced" to a suitable number of points. This has been accomplished by fixing some key stage along the evolutionary path, and distributing for each track the same number of points between two consecutive stages. This allows a straightforward interpolation for producing isochrones of a given age, and for determining tracks and isochrones for other metallicities within the range spanned by the computed grid of models.

  Example:

  0130z402y303aes.nor_c04ae ---> 1.30 Mo canonical model with Z=4.0E-2 and Y=0.303

The evolutionary models have been also transferred from the theoretical plane to the Stroemgren Photometric System. This set of models can be downloaded as a single compressed tar archive. In this case each file displays: in the fifth line - 1) the number of evolutionary points, 2) the global metallicity [M/H], 3) the abundance by mass of metals (Z), 4) the initial He abundance (Y), 5) the inital mass (in solar unit); starting from the ninth line the following quantities are listed:

 
  1 column) the logarithm of the age in years;
  2 column) the actual mass in solar units;  
  3 column) the logarithm of the surface luminosity in solar unit;
  4 column) the logarithm of the effective temperature (K);
  5 column) the y absolute magnitude (My);
  6 column) the (u-b) color;
  7 column) the (u_0-b) color; 
  8 column) the (b-y) color; 
  9 column) the m_1 color index; 
 10 column) the c_1 color index; 
 11 column) the c_1_0 color index;
 12 column) the H_beta color index;
 13 column) the hk color index;
 

from the Zero Age main Sequence until the first few thermal pulses (for masses larger than 0.7Mo).

All color indices have been normalized on Vega, but the hk color index that have been normalized on HD83373 by assuming T_eff=10550K, log(g)=4.0, [M/H]=0.0 and v_t= 2.0 km/s. The index 0 means reduction to airmass equal to 0.0 from indices computed for airmasses equal to 1 and 2 (see Kurucz, R.L. 1979, ApJS, 40, 1). For details about the adopted color - effective temperature relations, bolometric correction scale, we refer to:

Pietrinferni, Cassisi, Salaris & Castelli (2006, ApJ, 642, 797)

Castelli, F. & Kurucz, R.L. 2006, A&A, 454, 333

and to http://wwwuser.oat.ts.astro.it/castelli/colors.html. The coding of the file names is the same adopted for the tracks in the standard Johnson-Cousins photometric system. If requested we can provide also models transferred in the Stroemgren Photometric Systems by using the color - effective temperature relations provided by Clem, J.L., VandenBerg, D.A., Grundahl, F. & Bell, R.A. 2004, AJ, 127, 1227.

As for the choice of the key stages, we provide some information in the following.

In order to accurately sampling the morphology of the evolutionary tracks we have adopted 16 key stages along the evolutionary track, more in detail:

Key point
Evolutionary phase
1
Starting of the central H-burning phase
2
First Minimum in Teff for high-mass or Xc=0.30 for low-mass stars
3
Maximum in Teff along the Main Sequence - TURN OFF POINT
4
Maximum in logL for high-mass or Xc=0.0 for low-mass stars
5
Minimum in logL for high-mass or Base of the RGB for low-mass stars
6
The maximum luminosity during the RGB Bump
7
The minimum luminosity during the RGB Bump
8
Tip of the RGB
9
Start quiescent central He-burning phase
10
Central abundance of He equal to 0.55
11
Central abundance of He equal to 0.50
12
Central abundance of He equal to 0.40
13
Central abundance of He equal to 0.20
14
Central abundance of He equal to 0.10
15
Central abundance of He equal to 0.00
16
When the energy produced by the CNO cycle is larger than that provided by the He burning during the AGB (Lcno > L3alpha)

Low-mass stars denotes in this case all objects which do not develop a convective core during the whole central H-burning phase; the high-mass structures are all the others.

For those structures which do not present the Bump along the RGB, we have - arbitrarily - chosen as representative of the key points 6 and 7, two points whose brightness was intermediate between the luminosities corresponding to the key points 5 and 8.

The correspondence between key stages and rows is the following:

Key stage
Row
1
1
2
200
3
260
4
320
5
390
6
760
7
790
8
1190
9
1200
10
1350
11
1450
12
1550
13
1630
14
1710
15
1850
16
2000

For more details about the adopted key stages, please contact one of the authors.

For each chemical composition, we also provide a large set of horizontal branch (HB) models corresponding to the same RGB star progenitor - whose age at the RGB tip is of the order of 12/13Gyrs - but different assumptions about the total stellar mass of the HB structure.

 The coding of the file names is as follows:

 bcdfMpqZghiYlmnaes.nor_c04aes
      |
      | evolutionary track for a model with --> initial mass = b.cdf Mo
	                                    --> initial mass of the RGB progenitor
	   			                M = p.q Mo
                                            --> metallicity Z= g.h x 10^(i)
                                            --> initial He abundance of the
					        RGB progenitor Y = 0.lmn
                                            --> misture = aplha enhanced (ae)


The suffix "s" indicates models computed by adopting a Standard evolutionary scenario (no atomic diffusion, no overshooting). The suffix "nor" indicates that the evolutionary sequence has been "reduced" to a suitable number of points by fixing some key points - suitable chosen - along the evolutionary track.


  Example:

  0513m08z104y245aes.nor_c04ae ---> 0.513 Mo HB model with a canonical RGB progenitor with
                                    mass equal to 0.8Mo, metallicity Z=1.0E-4 and initial
			            He content equal to Y=0.245.


Each files display: in the fifth line - 1) the number of evolutionary points, 2) the global metallicity [M/H], 3) the abundance by mass of metals (Z), 4) the initial He abundance (Y), 5) the inital mass (in solar unit); starting from the ninth line the following quantities are listed:

  1 column) the logarithm of the age in years (the age of 1Myr corresponds to the ZAHB);
  2 column) the logarithm of the surface luminosity in solar unit;
  3 column) the logarithm of the effective temperature (K);
  4 column) the visual absolute magnitude;
  5 column) the (B-V) color;
  6 column) the (U-B) color;
  7 column) the (V-I) color;
  8 column) the (V-R) color;
  9 column) the (V-J) color; 
 10 column) the (V-K) color; 
 11 column) the (V-L) color; 
 12 column) the (H-K) color; 

from the Zero Age Horizontal Branch (ZAHB) until the advanced evolutionary phase of double shell burning or the beginning of the White dwarf cooling sequence.

The evolutionary models have been also transferred from the theoretical plane to the Stroemgren Photometric System. This set of models can be downloaded as a single compressed tar archive. In this case each file file displays: in the fifth line - 1) the number of evolutionary points, 2) the global metallicity [M/H], 3) the abundance by mass of metals (Z), 4) the initial He abundance (Y), 5) the inital mass (in solar unit); starting from the ninth line the following quantities are listed:

 
  1 column) the logarithm of the age in years (the age of 1Myr corresponds to the ZAHB);
  2 column) the logarithm of the surface luminosity in solar unit;
  3 column) the logarithm of the effective temperature (K);
  4 column) the y absolute magnitude (My);
  5 column) the (u-b) color;
  6 column) the (u_0-b) color; 
  7 column) the (b-y) color; 
  8 column) the m_1 color index; 
  9 column) the c_1 color index; 
 10 column) the c_1_0 color index;
 11 column) the H_beta color index;
 12 column) the Ca (or hk) color index;
 

from the Zero Age Horizontal Branch (ZAHB) until the advanced evolutionary phase of double shell burning or the beginning of the White Dwarf cooling sequence. All color indices have been normalized on Vega, but the Ca (hk) color index that have been normalized on HD83373 by assuming T_eff=10550K, log(g)=4.0, [M/H]=0.0 and v_t= 2.0 km/s. The index 0 means reduction to airmass equal to 0.0 from indices computed for airmasses equal to 1 and 2 (see Kurucz, R.L. 1979, ApJS, 40, 1). For details about the adopted color - effective temperature relations, bolometric correction scale, we refer to:

Pietrinferni, Cassisi, Salaris & Castelli (2006, ApJ, 642, 797)

Castelli, F. & Kurucz, R.L. 2006, A&A, 454, 333

and to http://wwwuser.oat.ts.astro.it/castelli/colors.html. The coding of the file names is the same adopted for the tracks in the standard Johnson-Cousins photometric system. If requested we can provide also the models transferred in the Stroemgren Photometric Systems by using the color - effective temperature relations provided by Clem, J.L., VandenBerg, D.A., Grundahl, F. & Bell, R.A. 2004, AJ, 127, 1227.

As for the choice of the key stages, we provide some information in the following.

In order to accurately sampling the morphology of the HB tracks we have adopted 9 key stages along the evolutionary track, more in detail:

Key point
Evolutionary phase
1
Starting of the central He-burning phase
2
Central abundance of He equal to 0.500
3
Central abundance of He equal to 0.400
4
Central abundance of He equal to 0.200
5
Central abundance of He equal to 0.100
6
Central abundance of He equal to 0.005
7
Maximum in luminosity along the clump on the AGB
8
Minimum in luminosity along the clump on the AGB
9
Maximum in luminosity all along the track

The correspondence between key stages and rows is the following:

Key stage
Row
1
1
2
130
3
180
4
300
5
370
6
450
7
600
8
650
9
900

For more details about the adopted key stages, please contact one of the authors.

In case one is interested in the complete evolutionary track (i.e, a non normalized track) as well as to more information about the models (such as burnings, internal structure and so on) we will be pleased to provide them upon request. All comments/suggestions/requests are welcome. We hope that this database will be useful to your work!

Our best regards!!!

Request Form