************************************************************ ************************************************************ ** TABLES OF EVOLUTIONARY TRACKS AND ISOCHRONES ** ** FOR ZERO-METALLICITY STARS I. ** ************************************************************ ************************************************************ This directory contain the data files of the paper "Zero-metallicity stars I. Evolution at constant mass" by Paola Marigo, Leo Girardi, Cesare Chiosi, and Peter R. Wood (2001), Astronomy and Astrophysics 371, 152. Please refer to this paper for a complete description of the models. ************************************************************ TABLES OF EVOLUTIONARY TRACKS ************************************************************ They are in the files ms*z0.dat and hb*z0.dat. Files with name starting with ms (e.g. ms00300z0.dat) contain the tracks computed from the ZAMS on, whereas those starting with hb (e.g. hb00100z0.dat) contain tracks evolved from the ZAHB on. The stellar mass is indicated in the filename, in units of hundredths of solar mass. For instance: ms00300z0.dat --> track for a 3.0 Msun, Z=0 star, from the ZAMS up to the TP-AGB. hb00100z0.dat --> track for a 1.0 Msun, Z=0 star, from the ZAHB up to the TP-AGB. EACH DATA FILE CONTAINS THE FOLLOWING INFORMATION: Column (1) age/yr --> stellar age in yr; Column (2) logL --> logarithm of surface luminosity (in solar units), log(L/Lsun); Column (3) logTef --> logarithm of effective temperature (in K), log(Teff/K); Column (4) grav --> logarithm of surface gravity (in cgs units); Column (5) logTc --> logarithm of central temperature (in K); Column (6) logrho --> logarithm of central density (in cgs units); Column (7) Xc,Yc --> mass fraction of either hydrogen (up to the central H-exhaustion) or helium (later stages) in the stellar centre; Column (8) Xc_C --> mass fraction of carbon in the stellar centre; Column (9) Xc_O --> mass fraction of oxygen in the stellar centre; Column (10) Q_conv --> fractional mass of the convective core; Column (11) Q_disc --> fractional mass of the first mesh point where the chemical composition differs from the surface value; Column (12) L_H/L --> the luminosity provided by H-burning reactions as a fraction of the surface luminosity; Column (13) Q1_H --> fractional mass of the inner border of the H-rich region; Column (14) Q2_H --> fractional mass of the outer border of the H-burning region; Column (15) L_He/L --> the luminosity provided by He-burning reactions as a fraction of the surface luminosity; Column (16) Q1_He --> fractional mass of the inner border of the He-burning region; Column (17) Q2_He --> fractional mass of the outer border of the He-burning region; Column (18) L_C/L --> the luminosity provided by C-burning reactions as a fraction of the surface luminosity; Column (19) L_nu/L --> the luminosity lost by neutrinos (hence negative) as a fraction of the surface luminosity; Column (20) Q_Tmax --> fractional mass of the point with the highest temperature inside the star; Column (21) stage --> label indicating particular evolutionary stages (see the paper for details). ************************************************************ TABLES OF ISOCHRONES ************************************************************ The isochrones are in the file isocz0.dat . It contains a complete series of isochrones with log(age/yr) values going from 6.60 to 10.25 (i.e. from 0.002 to 17.8 Gyr), at equally spaced intervals of Delta(log age)=0.05 (i.e., two consecutive isochrones differ by only 12 percent in their ages.) FOR EACH ISOCHRONE, THE FOLLOWING INFORMATION IS PRESENTED: HEADER LINE: contains the exact age and metallicity value of the isochrone; Column (1) log(age/yr) --> logarithm of the age; Column (2) M_ini --> initial mass of the star; Column (3) M_act --> actual mass of the star, i.e., the mass obtained considering the previous history of mass-loss; Column (4) logL/Lo --> logarithm of surface luminosity (in solar units), log(L/Lsun); Column (5) logTef --> logarithm of effective temperature (in K), log(Teff/K); Column (6) logG --> logarithm of surface gravity (in cgs units); Column (7) Mbol --> absolute bolometric magnitude; Column (8) Mu --> absolute magnitude in the U pass-band; Column (9) Mb --> absolute magnitude in the B pass-band; Column (10) Mv --> absolute magnitude in the V pass-band; Column (11) Mr --> absolute magnitude in the R pass-band; Column (12) Mi --> absolute magnitude in the I pass-band; Column (13) Mj --> absolute magnitude in the J pass-band; Column (14) Mh --> absolute magnitude in the H pass-band; Column (15) Mk --> absolute magnitude in the K pass-band; Column (16) FLUM --> indefinite integral of the Salpeter IMF by number (see the paper for more details); From the above quantities, broad-band colours can be easily derived. We also remark that the initial mass M_ini (and not M_act) is the useful quantity for population synthesis calculations, since together with the initial mass function it determines the relative number of stars in different sections of the isochrones. Also the quantity FLUM can be used for this purpose. SUMMARY TABLE OF THE ISOCHRONES A summary table of the isochrones can be found in the file isocsummz0.dat It contains a list of some significant stages along the complete series of isochrones presented in isocz0.dat. FOR EACH ISOCHRONE, THE FOLLOWING INFORMATION IS PRESENTED: HEADER LINE: contains the exact age and metallicity value of the isochrone; Column (1) log(age/yr) --> logarithm of the age; Column (2) M_ini --> initial mass of the star; Column (3) M_act --> actual mass of the star, i.e., the mass obtained considering the previous history of mass-loss; Column (4) logL/Lo --> logarithm of surface luminosity (in solar units), log(L/Lsun); Column (5) logTef --> logarithm of effective temperature (in K), log(Teff/K); Column (6) logG --> logarithm of surface gravity (in cgs units); Column (7) Mv --> absolute magnitude in the V pass-band; Column (8) U-B --> the U-B colour; Column (9) B-V --> the B-V colour; Column (10) V-I --> the V-I colour; Column (11) stage --> the stage along the isochrone; The stages represented in the tables are, in this sequence: TO --> the turn-off point, i.e. the point of highest Teff during the core-H burning phase. Te-m, Te-M, L-M --> If present, Te-m and Te-M signal the coolest and hottest points, respectively, of stars in the overall contraction phase at the end of core-H burning. RGBb and RGBt--> the base and tip of the RGB, respectively. BHeb --> the beginning of the CHeB phase. Te-m, Te-M --> If present, Te-m and Te-M signal the coolest and hottest points, respectively, for CHeB stars. For the youngest isochrones, Te-M represents the maximum extension of the Cepheid loop. EHeb --> the end of the CHeB phase. L-M, L-m --> In the oldest isochrones, L-M and L-m limit the luminosity range of early-AGB stars; this interval corresponds to the clump of early-AGB stars in colour-magnitude diagrams. 1TP --> the beginning of the thermally pulsing AGB phase. Cb --> the stage of C-ignition in the cases the AGB phase do not occur. ************************************************************ INTEGRATED BROAD-BAND COLOURS OF SSPs ************************************************************ Integrated Johnson-Cousins broad-band colours of single-burst stellar populations (SSP), are contained in the file sspcolor_z0.dat The integrated colours, as well as the absolute V magnitude, are tabulated as a function of age. They are computed assuming a simple Salpeter IMF over the complete mass interval from 100 down to 0.7 Msun. The IMF is normalized to 1 Msun, and its low-mass cut is such as to reproduce a mass-to-light ratio of about M/L_V=0.2 at an age of 10^8 yr (see eg. Girardi & Bica, 1993, A&A 274, 279). We remark that the integrated colours depend little on the choice of IMF. The velocity of fading in the V-band, on the contrary, is primarily determined by the IMF slope.