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L’evoluzione stellare: l’orologio

L’evoluzione stellare: l’orologio. Evoluzione di stelle di massa piccola, intermedia e alta Features sul HRD particolarmente importanti per il problema Sistematica con la metallicita’ Caveats. 100 M O. ZAMS. 2.5 M O. 20 M O. PAGB0.6 M O. PN. 5 M O. 5 M O. 2.5 M O. 2.5 M O.

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L’evoluzione stellare: l’orologio

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  1. L’evoluzione stellare: l’orologio Evoluzione di stelle di massa piccola, intermedia e alta Features sul HRD particolarmente importanti per il problema Sistematica con la metallicita’ Caveats Lectures on Stellar Populations

  2. 100 MO ZAMS 2.5 MO 20 MO PAGB0.6 MO PN 5 MO 5 MO 2.5 MO 2.5 MO RGB ZAHB To WD 1 MO 1MO Evolutionary Tracks Padova 94 set Z=Zo Y=0.28 Lines of constant radii: R=1,10,100,1000 Ro R=0.008,0.013,0.014 Ro (MWD=1,0.6,0.5 Mo) Lectures on Stellar Populations

  3. 100Ro 2 Mo 0.8 Mo RGB Bump 10 Ro RGB evolution Back to HRD Lectures on Stellar Populations

  4. 1.2 Mo 1 Mo RGB : bump and LF Back to HRD Lectures on Stellar Populations

  5. RGB tip 1 Ro 10 Ro 100 Ro RGB tip P-EAGB RGB base 0.12 0.07 0.03 M tr Flash and After Back to HRD Lectures on Stellar Populations

  6. 15 Age indicator Distance ind Lmax,He 9 Mo 7 6 TRGB Lmin,He 5 4 3 2.2 Mo 10 Ro ZAHB Clump and Loops Back to HRD Lectures on Stellar Populations

  7. BUMP RGB 5 Mo 4 Mo 3 Mo 2.2 Mo BUMP 1.5 Mo with cost=-0.5 RGB 1 Mo with cost=-1 AGB Bump Lectures on Stellar Populations

  8. Clump Clump Bump Bump Bump PMS LFRGBHBAGB Lectures on Stellar Populations

  9. A Field in the Halo of Centaurus A(Rejkuba et al 2005) Lectures on Stellar Populations

  10. TAGB Ist Pulse TRGB First Pulse and TAGB Lectures on Stellar Populations

  11. Massive Stars Evolution affected by MASS LOSS OVERSHOOTING Chiosi and Maeder 1986 Lectures on Stellar Populations

  12. BSG RSG WR C stars Miras Ceph Clump HB RRLyr WD Where the Stars are Back to HRD Dots are equally spaced in There are 1000 dots along each track Lectures on Stellar Populations

  13. 30 Mo 15 Mo 5 Mo AGB Manque’ 3 Mo Clumps Post E-AGB Clumps 0.9 Mo 0.55 Mo 0.6 Mo 0.5 Mo Dependence on Metallicity Lectures on Stellar Populations

  14. RGB phase transition overshooting tot He burning MS rgb Evolutionary Lifetimes Lectures on Stellar Populations

  15. TIP Base RGB Luminosities Lectures on Stellar Populations

  16. Ist Pulse He burn L-band RGB trans Helium Burning and beyond Lectures on Stellar Populations

  17. Isochrones Girardi et al. 2002 • As Z increases: • isochrones get • fainter and redder • loops get shorter • WR stars are more • easily produced Lectures on Stellar Populations

  18. Uncertainties and wish list Core Convection: affects star’s luminosity H and He lifetimes shape of tracks around Mhook first H shell burning and runway for intermediate mass stars MS width location of RGB bump values of Mtr and Mup ratios N(HB)/N(AGB) loops extension Mass Loss: on the RGBaffects Temperature extension of HB on the AGB affects value of Mup and TAGB for massive stars affects surface abundances, upper limit of Red SGs, productions of WR .. Opacity: affects MS width occurrence and extension of loops Blue to Red ratio Mixing Length, rotation, diffusion, meridional circulation, nuclear reactions… Separate dependence on Y and Z is important Lectures on Stellar Populations

  19. What have we learnt To place on the HRD whatever mass at whatever age we want to pay attention to: • Mtr Mup Mhook : lifetimes and tracks discontinuities • Place correctly RGB Tip (as distance indicator) • Describe accurately the evolution in core He burning close to RGB transition (Lum extension during evolution) • Allow spread of envelope masses for HB stars • Describe extension of the loops, location of BSG, Back-to-the-Blue evolution of high mass stars • …………. AND if we include a metallicity spread Correctly describe all these systematics as a function of Metallicity Lectures on Stellar Populations

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