Asteroseismology The Real Music of the Spheres 1

Asteroseismology The Real Music of the Spheres 1

Sir Arthur Stanley Eddington: The Internal Constitution of the Stars 1926 Sir Arthur Eddington (1882 – 1944) At first sight it would seem that the deep interior of the sun and stars is less accessible to scientific investigation than any other region of the universe. 2

Our telescopes may probe farther and farther into the depths of space; but how can we ever obtain certain knowledge of that which is hidden behind substantial barriers? 3

What appliance can pierce through the outer layers of a star and test the conditions within? 4

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3 D oscillations – stars radial modes Cepheids P 1/P 0= 0. 7 string P 1/P 0= 0. 33 6

Cepheid variables Cepheid Horn by Zoltan Kollath & Geza Kovács, Konkoly Observatory, Budapest; Robert Buchler, Florida 7

A giant solar-like oscillator http: //www. lcse. umn. edu/ 8

Asteroseismology 9

Angular structure of the modes n n = number of radial nodes = total number of surface nodes m = number of surface nodes that are lines of longitude n – m = number of surface nodes that are lines of latitude 10

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Dipole modes l=1, m=-1 l=1, m=0 l=1, m=+1 12

Quadrupole modes l=2, m=-2 l=2, m=-1 l=2, m=0 13

Rotation of the sun 14

p modes and g modes J. P. Cox, 1980, Theory of Stellar Pulsation, Princeton University Press. 15

p modes and g modes p modes (n, ) = (8, 100), (8, 2) g mode (n, ) = (10, 5) Gough et al. , 1996, Science, 272, 1281 16

The sun as a star - Bi. SON 17

The sun as a star - GOLF large separation small separation 18

An asteroseismic HR diagram 19

Solar-like Oscillations in Centauri Bedding, T. , et al. 2004, Ap. J, 614, 380 n UVES & UCLES 42 oscillation frequencies n ℓ = 1 -3 n n n Mode lifetimes only 1 -2 days Noise level = 2 cm s-1! 20

Modelling Cen A and B n n n Stellar model in good agreement with the astrometric, photometric, spectroscopic and asteroseismic data t = 6. 52 ± 0. 30 Gyr Initial Y = 0. 275 ± 0. 010 Initial Z/X = 0. 043 ± 0. 002 Radii of both stars determined with high precision (errors smaller than 0. 3%) compatible with interferometric results of Kervella et al. (differences smaller than 1%) Eggenberger, P. , Charbonnel, C. , Talon, S. , Meynet, G. , Maeder, A. , Carrier, F. , Bourban, G. 2004, A&A, 417, 235 21

Oscillations and planets n Stellar activity, convection and pulsation are “noise” to planet-hunters n Planets are “noise” to asteroseismologists n The two fields are not just complementary n It is mandatory to do both together at cm s-1 precision 22

Arae n V = 5. 15 n G 3 IV-V n Prot = 22 days n 14 M planet; Porb = 9. 55 days n 43 p-modes detected n 8 -day single-site HARPS study Bouchy, F. , Bazot, M. , Santos, N. C. , Vauclair, S. , Sosnowska, D. , 2005, A&A, 440, 609 23

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Arae – the 14 M planet Bouchy, F. , Bazot, M. , Santos, N. C. , Vauclair, S. , Sosnowska, D. , 2005, A&A, 440, 609 26

Arae – ~8 -min pulsations Bouchy, F. , Bazot, M. , Santos, N. C. , Vauclair, S. , Sosnowska, D. , 2005, A&A, 440, 609 27

Arae Bouchy, F. , Bazot, M. , Santos, N. C. , Vauclair, S. , Sosnowska, D. , 2005, A&A, 440, 609 28

Resolving pulsations in the atmospheres of ro. Ap stars Don Kurtz Vladimir Elkin Gautier Mathys 29

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Theoretical expectation = 0. 1 = 0. 7 Saio, 2005, MNRAS, 360, 1022 32

HD 101065 Ba. II Nd. III 33

~ 10 -2 ~ 10 -5 34

HD 99563 35

~ 10 -2 ~ 10 -5 << 10 -5 36

Gautschy, Saio & Harzenmoser, 1998, MNRAS, 301, 31 37

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HD 154708 Hubrig, S. , Nesvacil, N. , Schöller, M. , North, P. , Mathys, G. , Kurtz, D. W. , Wolff, B. , Szeifert, T. , Cunha, M. S. , Elkin, V. G. , 2005, A&A, 440, L 37 41

HD 154708 Kurtz, D. W. , Elkin, V. G. , Mathys, G. , Hubrig, Wolff, B. , Savanov, I. , 2006, MNRAS, submitted 42

We are seeing the ro. Ap star atmospheres in more detail than is possible for any star other than the sun 43

White dwarfs – g-mode pulsators 44

PG 1159 -035 45

PG 1159 -035 n Tsurf = 123, 000 - 124, 000 K; log g 7 n 1000 f 2600 Hz; 385 P 1000 s n 125 frequencies; >100 modes n M = 0. 586 ± 0. 003 M n the star is compositionally stratified 46

BPM 37093 n DAV n M = 1. 09 M n Teff = 11730 K n Partially crystallized C-O core Metcalfe, T. S. , Montgomery, M. H. , Kanaan, A. 2004, Ap. J, 605, 133 Kanaan et al. , 2005, A&A, 432, 219 Brassard & Fontaine, 2005, Ap. J, 622, 572 47

BPM 37093 48

p modes: EC 14026 stars - sd. BV 49

PG 1336 + 018 50

p modes: Cephei stars 51

HD 129929 = V 836 Cen 20 -yr multicolour photometry Core overshooting with a. OV = 0. 1 Non-rigid rotation: 4 times faster near core Aerts et al. , 2003, Science, 300, 926 Asteroseismology of HD 129929: Core overshooting and nonrigid rotation 52

g modes: SPB stars 53

Continuous coverage - MOST n n n HD 163830 SPB star V = 9. 3 B 5 II/III 37 days coverage 20 frequencies detected 54

HD 163830 Aerts, C. ; De Cat, P. ; Kuschnig, R. ; Matthews, J. M. ; Guenther, D. B. ; Moffat, A. F. J. ; Rucinski, S. M. ; Sasselov, D. ; Walker, G. A. H. ; Weiss, W. W. , 2006, Ap. J, 642, L 65 55

HD 163830 Aerts, C. ; De Cat, P. ; Kuschnig, R. ; Matthews, J. M. ; Guenther, D. B. ; Moffat, A. F. J. ; Rucinski, S. M. ; Sasselov, D. ; Walker, G. A. H. ; Weiss, W. W. , 2006, Ap. J, 642, L 65 56

Dome C - Concordia 57

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Seeing 2003 -2004: statistics 50% 0. 5 0. 1 0. 3 0. 5 1 3 Seeing distribution (log-normal) N data 17148 Std deviation 0. 39 Mean seeing (arcsec) 0. 65 Seeing max 5. 22 Median seeing 0. 54 Seeing min 0. 10 60

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What appliance can pierce through the outer layers of a star and test the conditions within? 62

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Stellarmusicno 1 Stellar acoustics as input for music composition Zoltán Kolláth Konkoly Observatory, Budapest, Hungary Jenő Keuler Institute for Musicology, Budapest, Hungary http: //www. konkoly. hu/staff/kollath/stellarmusic/ 64

Photometry - HR 1217 WET Xcov 20 s = 14 mag precision Kurtz et al. , 2005, MNRAS, 358, 651 65

What can you do with the frequencies in ro. Ap stars? – HR 1217 66

A model and prediction Cunha, M. 1999, Ph. D thesis, Cambridge Cunha, M. Gough, D. , 2001, MNRAS, 319, 1020 Bigot et al. 2000, A&A, 356, 218 67

HR 1217 photometric campaigns 68

HR 1217 photometric campaigns 69