J/A+A/544/A106 p-mode frequencies of the solar twin 18 Sco (Bazot+, 2012)
Estimating the p-mode frequencies of the solar twin 18 Sco.
Bazot M., Campante T.L., Chaplin W.J., Carfantan H., Bedding T.R.,
Dumusque X., Broomhall A.-M., Petit P., Theado S., Van Grootel V.,
Arentoft T., Castro M., Christensen-Dalsgaard J., do Nascimento Jr J.-D.,
Dintrans B., Kjeldsen H., Monteiro M.J.P.F.G., Santos N.C., Sousa S.,
Vauclair S.
<Astron. Astrophys. 544, A106 (2012)>
=2012A&A...544A.106B 2012A&A...544A.106B
ADC_Keywords: Stars, G-type ; Spectroscopy ; Models
Keywords: stars: individual: 18 Sco - stars: oscillations -
techniques: radial velocities - methods: data analysis
Abstract:
Solar twins have been a focus of attention for more than a decade,
because their structure is extremely close to that of the Sun. Today,
thanks to high-precision spectrometers, it is possible to use
asteroseismology to probe their interiors. Our goal is to use time
series obtained from the HARPS spectrometer to extract the oscillation
frequencies of 18 Sco, the brightest solar twin. We used the tools of
spectral analysis to estimate these quantities. We estimate 52
frequencies using a Markov Chain Monte-Carlo (MCMC) algorithm. After
examination of their probability densities and comparison with results
from direct MAP optimization, we obtain a minimal set of 21 reliable
modes. The identification of each pulsation mode is straightforwardly
accomplished by comparing to the well-established solar pulsation
modes. We also derived some basic seismic indicators using these
values. These results offer a good basis to start a detailed seismic
analysis of 18 Sco using stellar models.
Description:
Results from the estimation of the parameter of the spectrum model
using the Markov Chain Monte-Carlo (MCMC) algorithm described in
Sect.4. A burn-in sequence has been removed. The data is stored
in the form of an array [1975001x54] The first 52 columns give the
frequencies of the modes order by degree (13 l=0 modes, 13 l=1 modes,
13 l=2 modes, 13 l=3 modes). For each mode, they are sorted in
ascending order. The last two columns of each line give the parameters
Gamma1 and Gamma2.
Objects:
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RA (2000) DE Designation(s)
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16 15 37.27 -08 22 10.0 18 Sco = HR 6060
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File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
mcmc.dat 701 1975001 Markov Chain obtain from our MCMC simulation.
A burn-in sequence has been removed.
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Byte-by-byte Description of file: mcmc.dat
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Bytes Format Units Label Explanations
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1- 12 F12.10 Hz nu1 Frequency 1 (l=0)
14- 25 F12.10 Hz nu2 Frequency 2 (l=0)
27- 38 F12.10 Hz nu3 Frequency 3 (l=0)
40- 51 F12.10 Hz nu4 Frequency 4 (l=0)
53- 64 F12.10 Hz nu5 Frequency 5 (l=0)
66- 77 F12.10 Hz nu6 Frequency 6 (l=0)
79- 90 F12.10 Hz nu7 Frequency 7 (l=0)
92-103 F12.10 Hz nu8 Frequency 8 (l=0)
105-116 F12.10 Hz nu9 Frequency 9 (l=0)
118-129 F12.10 Hz nu10 Frequency 10 (l=0)
131-142 F12.10 Hz nu11 Frequency 11 (l=0)
144-155 F12.10 Hz nu12 Frequency 12 (l=0)
157-168 F12.10 Hz nu13 Frequency 13 (l=0)
170-181 F12.10 Hz nu14 Frequency 14 (l=1)
183-194 F12.10 Hz nu15 Frequency 15 (l=1)
196-207 F12.10 Hz nu16 Frequency 16 (l=1)
209-220 F12.10 Hz nu17 Frequency 17 (l=1)
222-233 F12.10 Hz nu18 Frequency 18 (l=1)
235-246 F12.10 Hz nu19 Frequency 19 (l=1)
248-259 F12.10 Hz nu20 Frequency 20 (l=1)
261-272 F12.10 Hz nu21 Frequency 21 (l=1)
274-285 F12.10 Hz nu22 Frequency 22 (l=1)
287-298 F12.10 Hz nu23 Frequency 23 (l=1)
300-311 F12.10 Hz nu24 Frequency 24 (l=1)
313-324 F12.10 Hz nu25 Frequency 25 (l=1)
326-337 F12.10 Hz nu26 Frequency 26 (l=1)
339-350 F12.10 Hz nu27 Frequency 27 (l=2)
352-363 F12.10 Hz nu28 Frequency 28 (l=2)
365-376 F12.10 Hz nu29 Frequency 29 (l=2)
378-389 F12.10 Hz nu30 Frequency 30 (l=2)
391-402 F12.10 Hz nu31 Frequency 31 (l=2)
404-415 F12.10 Hz nu32 Frequency 32 (l=2)
417-428 F12.10 Hz nu33 Frequency 33 (l=2)
430-441 F12.10 Hz nu34 Frequency 34 (l=2)
443-454 F12.10 Hz nu35 Frequency 35 (l=2)
456-467 F12.10 Hz nu36 Frequency 36 (l=2)
469-480 F12.10 Hz nu37 Frequency 37 (l=2)
482-493 F12.10 Hz nu38 Frequency 38 (l=2)
495-506 F12.10 Hz nu39 Frequency 39 (l=2)
508-519 F12.10 Hz nu40 Frequency 40 (l=3)
521-532 F12.10 Hz nu41 Frequency 41 (l=3)
534-545 F12.10 Hz nu42 Frequency 42 (l=3)
547-558 F12.10 Hz nu43 Frequency 43 (l=3)
560-571 F12.10 Hz nu44 Frequency 44 (l=3)
573-584 F12.10 Hz nu45 Frequency 45 (l=3)
586-597 F12.10 Hz nu46 Frequency 46 (l=3)
599-610 F12.10 Hz nu47 Frequency 47 (l=3)
612-623 F12.10 Hz nu48 Frequency 48 (l=3)
625-636 F12.10 Hz nu49 Frequency 49 (l=3)
638-649 F12.10 Hz nu50 Frequency 50 (l=3)
651-662 F12.10 Hz nu51 Frequency 51 (l=3)
664-675 F12.10 Hz nu52 Frequency 52 (l=3)
677-688 F12.10 Hz Gamma1 Linewidth Γ1 of Lorentzian at 2800µHz
690-701 F12.10 Hz Gamma2 Linewidth Γ2 of Lorentzian at 3600µHz
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Acknowledgements:
Michael Bazot, bazot(at)astro.up.pt
(End) Michael Bazot [CAUP, Portugal], Patricia Vannier [CDS] 16-Jul-2012