1. The Real Music of the Spheres
Asteroseismology
The Real Music of the Spheres

2. Sir Arthur Stanley Eddington: The Internal Constitution of the Stars
1926
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.
Sir Arthur Eddington
(1882 – 1944)

3. 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?

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

5. Asteroseismology

6. 3D oscillations – stars radial modes
Cepheids P1/P0= 0.7
string P1/P0= 0.33

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

8. A giant solar-like oscillator

9. Asteroseismology

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

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

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

14. Rotation of the sun

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

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

17. The sun as a star - BiSON

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

19. An asteroseismic HR diagram

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

21. Modelling  Cen A and B
Stellar model in good agreement with the astrometric, photometric, spectroscopic and asteroseismic data
t = 6.52 ± 0.30 Gyr
Initial Y = ± 0.010
Initial Z/X = ± 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

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

23.  Arae V = 5.15 G3IV-V Prot = 22 days 14 M planet; Porb = 9.55 days
43 p-modes detected
8-day single-site HARPS study
Bouchy, F., Bazot, M., Santos, N. C., Vauclair, S., Sosnowska, D., 2005, A&A, 440, 609

24.  Ara b : giant
Msini = 1.67 Jupiter masses
a = 1.5 AU
Porb = days
e = 0.31
 Ara c : giant
Msini = 3.1 Jupiter masses
a = 4.17 AU
Porb = 2986 days
e = 0.57
 Ara d : ??
Msini = 14 Earth masses
a = AU
Porb = 9.55 days
e = 0

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

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

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

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

32. Theoretical expectation
 = 0.7
 = 0.1
Saio, 2005, MNRAS, 360, 1022

33. HD
BaII
NdIII

34.  ~ 10-5
 ~ 10-2

35. HD99563

36.  ~ 10-5
 ~ 10-2
 << 10-5

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

41. HD154708
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, L37

42. HD154708
Kurtz, D. W., Elkin, V. G., Elkin, V. G., Mathys, G., Hubrig,  Wolff, B., Savanov, I., 2006, MNRAS, submitted

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

44. White dwarfs – g-mode pulsators

45. PG

46. PG
Tsurf = 123, ,000 K; log g  7
1000  f  2600 Hz; 385  P  1000 s
125 frequencies; >100 modes
M = ± M
the star is compositionally stratified

47. BPM 37093
DAV
M = 1.09 M
Teff = K
Partially crystallized C-O core
Metcalfe, T. S., Montgomery, M. H., Kanaan, A. 2004, ApJ, 605, 133
Kanaan et al., 2005, A&A, 432, 219
Brassard & Fontaine, 2005, ApJ, 622, 572

48. BPM 37093

49. p modes: EC stars - sdBV

50. PG

51. p modes:  Cephei stars

52. HD 129929 = V836 Cen 20-yr multicolour photometry
Core overshooting with aOV = 0.1
Non-rigid rotation: 4 times faster near core
Aerts et al., 2003, Science, 300, 926 Asteroseismology of HD129929: Core overshooting and nonrigid rotation

53. g modes: SPB stars

54. Continuous coverage - MOST
HD163830
SPB star
V = 9.3
B5II/III
37 days coverage
20 frequencies detected

55. HD
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, ApJ, 642, L65

56. HD
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, ApJ, 642, L65

57. Dome C - Concordia

60. Seeing 2003-2004: statistics 0.10 Seeing min 0.54 Median seeing 5.22
50%
0.5
0.1
0.3
0.5 1 3
Seeing distribution (log-normal)
0.10
Seeing min
0.54
Median seeing
5.22
Seeing max
0.65
Mean seeing (arcsec)
0.39
Std deviation
17148
N data

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

64. Stellarmusicno1 Stellar acoustics as input for music composition
Zoltán Kolláth Konkoly Observatory, Budapest, Hungary
Jenő Keuler Institute for Musicology, Budapest, Hungary

65. Photometry - HR 1217 WET Xcov20
= 14 mag
precision
Kurtz et al., 2005, MNRAS, 358, 651

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

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

68. HR 1217 photometric campaigns

69. HR 1217 photometric campaigns