Theoretical isochrones in several photometric systems I. Johnson-Cousins-Glass, HST/WFPC2, HST/NICMOS, Washington, and ESO Imaging Survey filter sets

SIGLEAvailable from: http://www.mpa-garching.mpg.de / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekDEGerman

The third dredge-up and the carbon star luminosity functions in the Magellanic Clouds

We investigate the formation of carbon stars as a function of the stellar mass and parent metallicity. Theoretical modelling is based on an improved scheme for treating the third dredge-up in synthetic calculations of thermally pulsing asymptotic giant branch (TP-AGB) stars. In this approach, the usual criterion based on a constant minimum core mass for the occurrence of dredge-up, M_c"m"i"n, is replaced by one on the minimum temperature at the base of the convective envelope, T_b"d"r"e"d, at the stage of the post-flash luminosity maximum. Envelope integrations allow then to determine M_c"m"i"n as a function of stellar mass, metallicity, and pulse strength (cf. Wood 1981), thus inferring if and when dredge-up first occurs. Moreover, the final possible shut down of the process is predicted. Extensive grids of TP-AGB models were computed by Marigo (1998) using this scheme. In this paper, we present and discuss the calibration of the two dredge-up parameters (i.e. efficiency #lambda# and T_b"d"r"e"d) aimed at reproducing the carbon star luminosity function (CSLF) in the LMC, using TP-AGB models with original metallicity Z = 0.008. In addition to this, the effects of different input quantities on the theoretical CSLF are analysed. It turns out that the faint tail is almost insensitive to the history of star formation rate (SFR) in the parent galaxy, contrarily to the bright wing which may be more affected by the details of the recent history. Actually, we find that the faint end of the CSLF is essentially determined by the temperature parameter T_b"d"r"e"d81 refs.Available from TIB Hannover: RR 4697(1116) / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekSIGLEDEGerman

Evolutionary tracks and isochrones for low- and intermediate-mass stars: from 0.15 to 7 M_sun, and from Z=0.0004 to 0.03

SIGLEAvailable from: http://www.mpa-garching.mpg.de / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekDEGerman