On the validity of the core-mass luminosity relation for TP-AGB stars with efficient dredge-up
نویسنده
چکیده
We investigate the validity of the core mass – luminosity relation (CMLR), originally described by Paczyński (1970), for asymptotic giant branch stars under the presence of third dredge-up events. We find, that models with efficient third dredge-up with less massive cores than those associated with hot bottom burning (Blöcker and Schönberner, 1991) do not obey the linear CMLR. Complete evolutionary calculations of thermal pulse stellar models which consider overshoot according to an exponential diffusive algorithm show systematically larger third dredge-up for lower core masses (0.55M <∼ MH <∼ 0.8M ) than any other existing models. We present and discuss the luminosity evolution of these models.
منابع مشابه
Is the core mass-luminosity relation violated by the occurrence of the third dredge-up?
The core mass-luminosity (Mc −L) relation of thermally pulsing asymptotic giant branch (TP-AGB) stars is a key ingredient in synthetic calculations of their evolution. Recently, Herwig et al. (1998) have presented full calculations of TPAGB models with strong dredge-up occurring already during early thermal pulses. The resulting luminosity evolution differs appreciably from the simple linear Mc...
متن کاملThird Dredge-up in Low Mass Stars: Solving the LMC Carbon Star Mystery
A long standing problem with asymptotic giant branch (AGB) star models has been their inability to produce the low-luminosity carbon stars in the Large and Small Magellanic Clouds. Dredge-up must begin earlier and extend deeper. We find this for the first time in our models of LMC metallicity. Such features are not found in our models of SMC metallicity. The fully implicit and simultaneous stel...
متن کاملThe evolution of AGB stars with convective overshoot
The influence of extended convective mixing (overshoot) on asymptotic giant branch stellar evolution is investigated in detail. The extended mixing is treated timedependently, and the efficiency declines exponentially with the geometric distance from the convective boundary. It has been considered at all convective boundaries, including the He-flash convection zone in the intershell region whic...
متن کاملOn the third dredge-up phenomenon in asymptotic giant branch stars
The third dredge-up phenomenon in asymptotic giant branch (AGB) stars is analyzed through evolutionary model calculations of a 3M⊙, solar metallicity star. The Schwarzschild criterion is used to test the stability of a given layer against convection, and the calculations are performed either with or without extra-mixing below the convective envelope. Based on these calculations, several questio...
متن کاملLINEAR PULSATION CHARACTERISTICS OF MIRA VARIABLE STARS
The linear adiabatic pulsation-periods of Mira variable stars have been derived. Approximately 2701[1]models were calculated for M = 0.7 MΘ to 2 MΘ stars with radii from 180 RΘ to 340 RΘ and luminosities from 2800 LΘ to 10,000 LΘ. The chemical composition of all models is (X,Z) = (0.7,0.02). From the result of this study, linear relations on Luminosity-Period-Mass relationship and luminosity-pe...
متن کاملذخیره در منابع من
با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید
عنوان ژورنال:
دوره شماره
صفحات -
تاریخ انتشار 1998