J/A+A/506/111Frequency analysis of HD 180642 (V1449 Aql) (Degroote+, 2009)

Evidence for nonlinear resonant mode coupling in the beta Cep star HD 180642 (V1449 Aql) from CoRoT space-based photometry. Degroote P., Briquet M., Catala C., Uytterhoeven K., Lefever K., Morel T., Aerts C., Carrier F., Auvergne M., Baglin A., Michel E. <Astron. Astrophys. 506, 111 (2009)> =2009A&A...506..111DADC_Keywords: Stars, variable ; Stars, early-typeKeywords: stars: oscillations - stars: variables: general - stars: individual: HD 180642 (V1449 Aql)Abstract: We present the CoRoT light curve of the beta Cep star HD 180642, assembled during the first long run of the space mission, as well as archival single-band photometry. Our goal is to analyse the detailed behaviour present in the light curve and interpret it in terms of excited-mode frequencies. After describing the noise properties in detail, we use various time series analyses and fitting techniques to model the CoRoT light curve, for various physical assumptions. We apply statistical goodness-of-fit criteria that allow us to select the most appropriate physical model fit to the data. We conclude that the light-curve model based on nonlinear resonant frequency and phase locking provides the best representation of the data. Interpretation of the residuals is dependent on the chosen physical model used to prewhiten the data. Our observational results constitute a fruitful starting point for detailed seismic stellar modelling of this large-amplitude and evolved beta Cep star.Description: The tables represent the results of the frequency analysis of various models: under assumption of stable, long-lasting and independent frequencies with constant amplitudes and phases, we arrive at the list in table1.dat. When assuming dependency in the form of combination frequencies, we arrive at the list presented in table2.dat. When allowing for time-dependent amplitudes and phases, we finally get tables3-10.Objects: --------------------------------------------------- RA (2000) DE Designation(s) --------------------------------------------------- 19 17 14.8 +01 03 34 HD 180642 = V* V1449 Aql ---------------------------------------------------File Summary:

FileName Lrecl Records Explanations

ReadMe 80 . This file table1.dat 99 200 Results of frequency analysis of the first 200 frequencies table2.dat 84 33 Frequency table with fixed combinations between parent and daughter modes tables.dat 53 62 Variable amplitude/phase model for a1, a2, a3, a4, phi1, phi2, phi3 and phi4 (tables 3-10 of the paper)

See also: B/corot : CoRoT observation log (CoRoT, 2009) J/A+A/361/245 : 6 new Beta Cep stars (Aerts, 2000)Byte-by-byte Description of file: table1.dat

Bytes Format Units Label Explanations

1- 3 I3 --- Seq Frequency ID number 5- 13 F9.6 d-1 f1 Frequency value 15- 22 F8.6 d-1 e_f1 Error on frequency value 24- 33 F10.6 uHz f2 Frequency value (identical to f1) 35- 42 F8.6 uHz e_f2 Error on frequency value (identical to e_f1) 44- 50 F7.5 --- A Ratio amplitude/average flux 52- 58 F7.5 --- e_A Error on amplitude 60- 66 F7.4 --- P ]-0.5,0.5] Phase (rad/2π) 68- 73 F6.4 --- e_P Error on phase 75- 79 F5.1 --- SNR Signal-to-noise ratio over 6d-1 interval 81- 85 F5.2 % VR Variance reduction 87- 92 F6.2 --- AIC Value of Akaike's Information Criterion 94- 99 F6.2 --- BIC Value of Bayesian Information Criterion

Byte-by-byte Description of file: table2.dat

Bytes Format Units Label Explanations

1- 8 F8.6 --- A Ratio amplitude/average flux 10- 18 F9.6 d-1 f1 Frequency value 20- 28 F9.5 uHz f2 Frequency value (same as f1) 30- 36 F7.4 --- P ]-0.5,0.5] Phase (rad/2π) 38- 42 F5.2 --- Ar ?=0.0 Relative amplitude (logarithmic) 44- 47 F4.2 --- e_Ar ?=0.0 Error on amplitude ratio 49- 53 F5.2 --- Pr ]-0.5,0.5]?=0.0 Relative phase (rad/2π) 55- 58 F4.2 --- e_Pr ]-0.5,0.5]?=0.0 Error on relative phase 60- 64 F5.1 --- SNR Signal-to-noise ratio over 6d-1 interval 66- 70 F5.2 % VR Variance reduction 72- 77 F6.2 --- AIC Value of Akaike's Information Criterion 79- 84 F6.2 --- BIC Value of Bayesian Information Criterion

Byte-by-byte Description of file: tables.dat

Bytes Format Units Label Explanations

1- 4 A4 --- Param [a1, a2, a3, a4, phi1, phi2, phi3, phi4] 6- 12 F7.5 --- A Ratio amplitude/average flux 14- 20 F7.5 --- e_A Error on amplitude 22- 27 F6.4 d-1 f1 Frequency value 29- 34 F6.4 d-1 e_f1 Error on frequency value 36- 42 F7.4 uHz f2 Frequency value (same as f1) 44- 48 F5.2 --- P ]-0.5,0.5] Phase (rad/2π) 50- 53 F4.2 --- e_P Error on phase

Acknowledgements: Pieter Degroote, pieterd(at)ster.kuleuven.ac.be(End)Pieter Degroote [IvS, Belgium], Patricia Vannier [CD] 17-Aug-2009

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