2009A&A...500L..21C


Query : 2009A&A...500L..21C

2009A&A...500L..21C - Astronomy and Astrophysics, volume 500, L21-24 (2009/6-3)

Mode lifetimes of stellar oscillations. Implications for asteroseismology.

CHAPLIN W.J., HOUDEK G., KAROFF C., ELSWORTH Y. and NEW R.

Abstract (from CDS):

Successful inference from asteroseismology relies on at least two factors: that the oscillations in the stars have amplitudes large enough to be clearly observable, and that the oscillations themselves be stable enough to enable precise measurements of mode frequencies and other parameters. Solar-like p modes are damped by convection, and hence the stability of the modes depends on the lifetime. We seek a simple scaling relation between the mean lifetime of the most prominent solar-like p modes in stars, and the fundamental stellar parameters. We base our search for a relation on the use of stellar equilibrium and pulsation computations of a grid of stellar models, and the first asteroseismic results on lifetimes of main-sequence, sub-giant and red-giant stars. We find that the mean lifetimes of all three classes of solar-like stars scale like Teff–4 (where Teff is the effective temperature). When this relation is combined with the well-known scaling relation of Kjeldsen & Bedding (1995A&A...293...87K) for mode amplitudes observed in narrow-band intensity observations, we obtain the unexpected result that the height (the maximum power spectral density) of mode peaks in the frequency power spectrum scales as g–2 (where g is the surface gravity). As it is the mode height (and not the amplitude) that fixes the S/N at which the modes can be measured, and as g changes only slowly along the main sequence, this suggests that stars cooler than the Sun might be as good targets for asteroseismology as their hotter counterparts. When observations are instead made in Doppler velocity, our results imply that mode height does increase with increasing effective temperature.

Abstract Copyright:

Journal keyword(s): convection - stars: oscillations - methods: data analysis

Simbad objects: 11

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Number of rows : 11
N Identifier Otype ICRS (J2000)
RA
ICRS (J2000)
DEC
Mag U Mag B Mag V Mag R Mag I Sp type #ref
1850 - 2022
#notes
1 * bet Hyi PM* 00 25 45.07036 -77 15 15.2860 3.52 3.41 2.79 2.28 1.94 G0V 576 0
2 * tau Cet PM* 01 44 04.0831371922 -15 56 14.927607677 4.43 4.22 3.50 2.88 2.41 G8V 1171 1
3 HD 49933 PM* 06 50 49.8309774552 -00 32 27.167495244   6.147 5.771 7.04   F3V 360 2
4 * alf CMi SB* 07 39 18.11950 +05 13 29.9552 0.82 0.79 0.37 -0.05 -0.28 F5IV-V+DQZ 1819 0
5 * ksi Hya ** 11 33 00.1150559 -31 51 27.443449 5.17 4.47 3.54 2.84 2.36 G7IIIb 247 0
6 * alf Boo RG* 14 15 39.67207 +19 10 56.6730 2.46 1.18 -0.05 -1.03 -1.68 K1.5IIIFe-0.5 2223 0
7 * alf Cen B PM* 14 39 35.06311 -60 50 15.0992 2.89 2.21 1.33     K1V 958 1
8 * alf Cen A SB* 14 39 36.49400 -60 50 02.3737 0.96 0.72 0.01     G2V 1203 0
9 * bet UMi V* 14 50 42.32580 +74 09 19.8142 5.32 3.55 2.08 0.97 0.21 K4-III 316 0
10 * eps Oph PM* 16 18 19.2897431 -04 41 33.034466 4.95 4.21 3.23 2.54 2.05 G9.5IIIbFe-0.5 229 0
11 * nu. Ind ** 22 24 36.8853892493 -72 15 19.488237466   5.94 5.29     G9VFe-3.1CH-1.5 263 0

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2022.05.24-17:59:44

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