Download presentation
Presentation is loading. Please wait.
Published byふみな こやぎ Modified over 6 years ago
1
Theoretical Interpretation of Power Spectra of Stellar Oscillations
H.Ando National Astronomical Observatory of Japan 9th, December, 2004
2
1. Observed Power Spectra of Stellar Oscillations
Procyon(F5 subg) Kambe (2000) Sun, αCen A, βHyi(G2 subg), η Boo(G0 subg), ξ Hya(G7 g) Bedding and Kjeldsen (2003) PASA, 20,
3
Spectrum of Procyon on 25,26,27,28, and 29, Dec., 2000
4
Summed spectrum of Procyon
on 25, 28, and 29, Dec., 2000
5
Power Spectra
6
Charactristics of Spectra
・shape of envelope (peak freq.) ・Asymptotic Formula Large separation Small Separation
8
Newly recognized points
・Not a simple distribution of amplitudes ・Deviation from equal spacing pattern
9
2. Theoretical background of Oscillations
・Radial Pulsation (l=0) acoustic modes(n=0,1,2,....) fn(r) ・non-radial oscillation(l≠0) acoustic modes (p-mode) (n,l,m) gravity modes (g-mode)(n,l,m) fn(r)Ylm(θ,φ)
10
Propagation diagram in Stars
ex. Procyon M=1.42 M⦿ (Prieto et. al 2002) #1(ZAMS) #51 (Procyon; L=7L⦿, Te=6530) #211(giant; L=7.7L⦿, Te=4490) Observed parameters of Procyon L= 7.04L⦿ , Te= 6530
11
Propagation diagram for #1
E-07 E-07 E-07 E-06 E-06 E-06 E-06 E-06 E-06 E-06 E-06 E-06 E-06 E-06 E-06 E-06 E-06 E-06 E-06 E-06 E-06 E-06 E-06 E-06 E-06 E-06 E-06 E-06 E-06 E-06 E-06 E-06 E-05 E-05 E-04 E-04 E-01 E-01 P G P G
12
E-06 E-06 E-06 E-06 E-06 E-06 E-04 E-06 E-06 E-06 E-06 E-06 E-06 E-06 E-04 E-06 E-06 E-06 E-06 E-03 E-06 E-06 E-03 E-06 E-06 E-03 E-06 E-04 E-05 E-05 E-05 E-04 E-04 E-04 E-04 P G P G
13
E-05 E-06 E-05 E-04 E-05 E-05 E-04 E-05 E-05 E-04 E-04 E-05 E-05 E-04 E-04 E-05 E-04 E-04 E-04 E-05 E-05 E-04 E-03 E-04 E-05 E-04 E-03 E-03 E-04 E-05 E-04 E-03 E-03 E-04 E-04 E-04 E-03 E-03 E-03 E-03 E-04 E-04 G P G P
14
Interaction bet ween Two potential wells
・ZAMS: Almost independent
15
・Advanced Evolution stage:
Mixed character Avoided Crossing
16
Mixed Mode
17
3. Prediction of Power Spectra
Basic assumptions ・Power ∝ (Input Energy)/(Kinetic Energy of mode), where KE is estimated with radial displacement, say(δr/r=1.0), at the surface. ・Input Energy Continuous spectrum by turbulent convection (Kolmogorov spectrum) We give Power ∝ f^n/(KE) n=2 : flat input energy (say, 1m/s at the surface) n=-2: Kolmogorov type input energy
24
Summary ・There are pulsation modes (l=0) beyond Cut-off frequency
・There are practical cut-off in lower end due to existence of g-modes’ territory ・Larger interaction of p-modes and g-modes in l=1 -modes with smaller amplitudes in mixed modes -frequencies of modes(l=1) shifted to modes with l=0 in lower frequency region
25
A possible suggestion Quantitative analysis of the Oscillation spectrum of ηBoo Guenther AJ, 612, , 2004
Similar presentations
© 2025 SlidePlayer.com. Inc.
All rights reserved.