The Linear Oscillation Zoo Within Giant Stars: A Probe Of Their Deep Interiors

Transcription

1 The Linear Oscillation Zoo Within Giant Stars: A Probe Of Their Deep Interiors Andrea Miglio School of Physics and Astronomy University of Birmingham

2 the zoo of red giants: a unique snapshot of stellar evolution Sun

3 the zoo of red giants determines oscillation spectrum 1.2 M sun

4 Miglio Montalban Noels Eds. 1 Astrophysics and Space Science Proceedings Andrea Miglio Josefina Montalban Arlette Noels Editors Red Giants as Probes of the Structure and Evolution of the Milky Way Red Giants as Probes of the Structure and Evolution of the Milky Way Red Giants as Probes of the Structure and Evolution of the Milky Way Series: Astrophysics and Space Science Proceedings Miglio, Andrea; Montalban, Josefina; Noels, Arlette (Eds.) 212, ISBN , Hardcover

5 Miglio Montalban Noels Eds. 1 Red Giants as Probes of the Structure and Evolution of the Milky Way Astrophysics and Space Science Proceedings Andrea Miglio Josefina Montalban Arlette Noels Editors Red Giants as Probes of the Structure and Evolution of the Milky Way Red Giants as Probes of the Structure and Evolution of the Milky Way Series: Astrophysics and Space Science Proceedings Miglio, Andrea; Montalban, Josefina; Noels, Arlette (Eds.) 212, ISBN , Hardcover PART 2: Internal structure, atmosphere, and evolution of red giants: current models and their uncertainties Evolution and internal structure of red giants Maurizio Salaris Uncertainties and systematics in stellar evolution models of Red Giant Stars Santi Cassisi Convection modelling and the morphology of RGBs in stellar clusters Paolo Ventura Helium burning in moderate-mass stars Achim Weiss Impact of rotational mixing on the global and asteroseismic properties of red giants Patrick Eggenberger 3D picture of the convective envelope of a rotating RGB star Ana Palacios Effects of rotation and thermohaline mixing in red giant stars Corinne Charbonnel 3D Model Atmospheres of Red Giant Stars Hans-Günter Ludwig

6 the zoo of red giants Oscilla/on frequencies Features in stellar interior - global stellar parameters specificity of seismic diagnostics: few examples

7 Mode Inertia Acoustic glitches in giants First evidence for a sharp-structure variation in a red giant CoRoT target HR7349 ν [µhz] Fig. 4. Mode inertias of radial modes (full dots), l = 1modes(asterisks) and l = 2modes(opentriangles)fora1.2M red-giant model. Δν detrended [µhz] ν [µhz] Fig. 5. Miglio Open squares et al. 21, represent A&A ν n,l computed from l =, 1, 2adiabatic frequencies in a 1.2 M red giant model. The solid line shows a sinusoidal component with amplitude decreasing with frequency (see Monteiro & Thompson 1998; Houdek & Gough 27) fitted to the l =, 1largeseparationdeterminedbyCarrieretal.21(dotswith error bars). 5. Conclusions l=2 Sun and solar-like stars, the amplitude of the periodic component depends on the envelope helium abundance (see e.g. Basu et al. 24; Houdek & Gough 27, and references therein). While CoRoT and Kepler observations will provide other targets and further reduce the uncertainty on the oscillation frequencies, a thorough study on the required precision in terms of seismic and non-seismic observational constraints, as well as and in terms of models, should be undertaken to aim for reliable seismic estimate of the envelope helium abundance in giants. Acknowledgements. JM acknowledges the Belgian Prodex-ESA for support (contract C931). FC is a postdoctoral fellow of the Funds for Scientific Research, Flanders (FWO). References Baglin, A., Michel, E., Auvergne, M., & The COROT Team. 26, in ESA Special Publication, Vol. 624, Proceedings of SOHO 18/GONG 26/HELAS I, Beyond the spherical Sun Ballot, J., Turck-Chièze, S., & García, R. A. 24, A&A, 423, 151 Basu, S., Mazumdar, A., Antia, H. M., & Demarque, P. 24, MNRAS, 35, 277 Bedding, T. R., Huber, D., Stello, D., et al. 21a, ApJ, 713, L176 Bedding, T. R., Kjeldsen, H., Campante, T. L., et al. 21b, ApJ, 713, 935 Borucki, W. J., Koch, D., Basri, G., et al. 21, Science, 327, 977 Carrier, F., De Ridder, J., Baudin, F., et al. 21, A&A, 59, A73 Catelan, M. 29, Ap&SS, 32, 261 Christensen-Dalsgaard, J. 22, Reviews of Modern Physics, 74,173 Christensen-Dalsgaard, J. 24, Sol. Phys., 22, 137 De Ridder, J., Barban, C., Baudin, F., et al. 29, Nature, 459, 398 Dupret, M., Belkacem, K., Samadi, R., et al. 29, A&A, 56, 57 Dziembowski, W. A., Gough, D. O., Houdek, G., & Sienkiewicz, R. 21, MNRAS, 328, 61 Eggenberger, P., Miglio, A., Montalban, J., et al. 21, A&A,59,A72 Frandsen, S., Carrier, F., Aerts, C., et al. 22, A&A, 394, L5 Gilliland, R. L., Brown, T. M., Christensen-Dalsgaard, J., et al. 21, PASP, 122, 131 Girardi, L. & Salaris, M. 21, MNRAS, 323, 19 Gough, D. O. 199, Lecture Notes in Physics, Berlin Springer Verlag, 367, 283 Hatzes, A. P. & Zechmeister, M. 27, ApJ, 67, L37 Hekker, S., Kallinger, T., Baudin, F., et al. 29, A&A, 56, 465 Houdek, G. & Gough, D. O. 27, MNRAS, 375, 861 Kippenhahn, R. & Weigert, A. 199, Stellar Structure and Evolution (Springer- Verlag) Kjeldsen, H. & Bedding, T. R. 1995, A&A, 293, 87

8 Mode Inertia Acoustic glitches in giants First evidence for a sharp-structure variation in a red giant CoRoT target HR7349 ν [µhz] Fig. 4. Mode inertias of radial modes (full dots), l = 1modes(asterisks) and l = 2modes(opentriangles)fora1.2M red-giant model. Δν detrended [µhz] ν [µhz] Fig. 5. Miglio Open squares et al. 21, represent A&A ν n,l computed from l =, 1, 2adiabatic frequencies in a 1.2 M red giant model. The solid line shows a sinusoidal component with amplitude decreasing with frequency (see Monteiro & Thompson 1998; Houdek & Gough 27) fitted to the l =, 1largeseparationdeterminedbyCarrieretal.21(dotswith error bars). 5. Conclusions l=2 Sun and solar-like stars, the amplitude of the periodic component depends on the envelope helium abundance (see e.g. Basu et al. 24; Houdek & Gough 27, and references therein). While CoRoT and Kepler observations will provide other targets and further reduce the uncertainty on the oscillation frequencies, a thorough study on the required precision in terms of seismic and non-seismic observational constraints, as well as and in terms of models, should be undertaken to aim for reliable seismic estimate of the envelope helium abundance in giants. Acknowledgements. JM acknowledges the Belgian Prodex-ESA for support (contract C931). FC is a postdoctoral fellow of the Funds for Scientific Research, Flanders (FWO). References Baglin, A., Michel, E., Auvergne, M., & The COROT Team. 26, in ESA Special Publication, Vol. 624, Proceedings of SOHO 18/GONG 26/HELAS I, Beyond the spherical Sun Ballot, J., Turck-Chièze, S., & García, R. A. 24, A&A, 423, 151 Basu, S., Mazumdar, A., Antia, H. M., & Demarque, P. 24, MNRAS, 35, 277 Bedding, T. R., Huber, D., Stello, D., et al. 21a, ApJ, 713, L176 Bedding, T. R., Kjeldsen, H., Campante, T. L., et al. 21b, ApJ, 713, 935 Borucki, W. J., Koch, D., Basri, G., et al. 21, Science, 327, 977 Carrier, F., De Ridder, J., Baudin, F., et al. 21, A&A, 59, A73 Catelan, M. 29, Ap&SS, 32, 261 Christensen-Dalsgaard, J. 22, Reviews of Modern Physics, 74,173 Christensen-Dalsgaard, J. 24, Sol. Phys., 22, 137 De Ridder, J., Barban, C., Baudin, F., et al. 29, Nature, 459, 398 Dupret, M., Belkacem, K., Samadi, R., et al. 29, A&A, 56, 57 Dziembowski, W. A., Gough, D. O., Houdek, G., & Sienkiewicz, R. 21, MNRAS, 328, 61 Eggenberger, P., Miglio, A., Montalban, J., et al. 21, A&A,59,A72 Frandsen, S., Carrier, F., Model Aerts, C., 1.2 et Mal. sun 22, A&A, 394, L5 Gilliland, R. L., Brown, T. M., Christensen-Dalsgaard, J., et al. 21, PASP, 122, 131 Girardi, L. & Salaris, M. 21, MNRAS, 323, 19 Gough, D. O. 199, Lecture Notes in Physics, Berlin Springer Verlag, 367, 283 Hatzes, A. P. & Zechmeister, M. 27, ApJ, 67, L37 Hekker, S., Kallinger, T., Baudin, F., et al. 29, A&A, 56, 465 Houdek, G. & Gough, D. O. 27, MNRAS, 375, 861 Kippenhahn, R. & Weigert, A. 199, Stellar Structure and Evolution (Springer- Verlag) Kjeldsen, H. & Bedding, T. R. 1995, A&A, 293, 87

9 Acoustic glitches in giants Sun: low-degree modes a. Red giant Base of the convective envelope Second helium ionization zone b. Sun Houdek & Gough, 27 Ballot et al. 24 Base of the convective envelope Second helium ionization zone

10 Acoustic glitches in giants Δν [µhz] Kepler data - field stars Δν [µhz] can we estimate envelope Y? first steps: H&H exercises ν max [µhz] ν max [µhz] test robustness in Kepler giants belonging to old open clusters thanks to B. Mosser

11 Period spacing: evolutionary state = 2π 2 l(l +1) ( r2 r 1 N dr ) 1 r Bedding et al. 211 Kepler He-burning RGB Mosser et al. 211 CoRoT

12 Period spacing: evolutionary state Kepler Bedding et al Msun 2. Msun 2.3 Msun 2.4, 2.5 Msun ATON stellar models + Adiabatic frequency computations (LOSC) Montalban, Miglio, Noels,Ventura, 211 in prep

13 Period spacing: Mass of the He core Y=.28 Z=.2 No overshooting 2.5 M 2.3 M 2.1 M in the secondary clump M(He core) vs Mstar depends on overshooting during the MS (Girardi et al. 1999, Castellani et al. 2) 3. M test of core-mixing during the MS evolutionary phase Montalban, Miglio, Noels, Ventura, 211 in prep

14 Mosser et al. in preparation Goupil et al. in preparation

15 the zoo of red giants: global parameters Mass and radius estimate: ( ) R = R ( νmax ν max, ) ( ) ( ν 2 Teff ν T eff, ).5, ( ) M = M ( νmax ν max, ) 3 ( ) ( ν 4 Teff ν T eff, ) 1.5. the paper were estimated by the direct method. W

16 Testing scaling relations 1 1 R/R sun R/R sun (seismo) Miglio. 211, ApSS

17 Testing scaling relations.3.2 (R R seismo )/R Miglio. 211, ApSS R/R sun

18 Testing scaling relations Stetson et al. photometry RGB stars used in this study RC stars used in this study empirical calibrations: clusters Kepler clusters e.g. NGC6791 Basu et al. 211, Stello et al. 211 V V NGC B V Miglio et al. 211, MNRAS in press Figure 1. Colour-magnitude diagram of NGC6791 (left panel) and NGC6819 al. (23) and Hole et al (29), respectively. RGB (RC) stars used in this wo

19 Testing scaling relations R seismo /R CMD R CMD Miglio et al. 211 MNRAS, in press RCMD using distance modulus from EB: (m-m)v=13.51±.6 Brogaard et al. 211 warning: need for 2-3% relative correction on RGB vs RC stars scaling

20 Distances Radii + Teff L + BC, de-reddened Ks apparent mag Distances (err ~15%)

21 Distances Radii + Teff L + BC, de-reddened Ks apparent mag 9 d (pc) Distances (err ~15%) 15 Kepler LRc1, a1: ~ 2 stars Sun 18 Mosser et al. 21 Kepler public data: ~ 1 stars Hekker et al. 211 gal. longitude 21 LRa1 LRc1 5 pc Galactic Centre

22 Distances LRa1 Miglio et al. 211, in preparation

23 CoRoT LRa1 vs. LRc1 Radius Mass.5.4 Fraction LRc1 LRa1 Fraction.3.2 LRc1 LRa1 observed R/R sun M/M sun.5.4 Fraction LRc1 LRa1 Fraction.3.2 LRc1 LRa1 simulated TRILEGAL R/R sun M/M sun

24 CoRoT LRa1 vs. LRc1 Radius Mass.5.4 Fraction LRc1 LRa1 Fraction.3.2 LRc1 LRa1 observed.1.1 Fraction R/R sun LRc1 LRa1 Fraction M/M sun LRc1 LRa1 Fraction Age Lrc1 Lra R/R sun M/M sun log(age [yr])

25 from Mass to Age log(g) < log(age [yr]) [Fe/H] 8.8 AGB mass good proxy for the age of RGB stars 8.6 He B RGB M [M ] sun.5.6

26 from Mass to Age why is it relevant to determine ev. state of a ~1 Rsun giant?

27 from Mass to Age why is it relevant to determine ev. state of a ~1 Rsun giant? constraints: [Fe/H], Teff,,, ev. state from age estimates using PARAM (as in Da Silva et al. 26, Nordstrom et al. 24).4.3 ev. state RC RGB Unknown PDF log(age [yr])

28 asteroseismic diagnostics in red giants global parameters M, R, ev. state (age) 9 local features in stellar interior e.g. signature of He ionisation info on detailed properties of the g-mode cavity Kepler Sun 18 LRc1 5 pc Galactic Centre LRa

29 thanks to M. Barbieri, Nice A.-M. Broomhall, W. Chaplin, Birmingham P. Eggenberger, Genève L. Girardi, Padova J. Montalbán, A. Noels, R. Scuflaire, MAD, Liège T. Morel, M. Valentini, Liège B. Mosser, Paris P. Ventura, F. D Antona, Roma G. Verner, London KASC WG 2, 8