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J/A+A/613/A70       Be stars in the exofield of CoRoT. II.       (Semaan+, 2018)

Study of a sample of faint Be stars in the exofield of CoRoT. II. Pulsation and outburst events: Time series analysis of photometric variations. Semaan T., Hubert A.M., Zorec J., Gutierrez-Soto J., Fremat Y., Martayan C., Fabregat J., Eggenberger P. <Astron. Astrophys. 613, A70 (2018)> =2018A&A...613A..70S (SIMBAD/NED BibCode)
ADC_Keywords: Stars, early-type ; Stars, Be Keywords: stars: early-type - stars: emission-line, Be - stars: rotation - stars: oscillations Abstract: The class of Be stars are the epitome of rapid rotators in the main sequence. These stars are privileged candidates for studying the incidence of rotation on the stellar internal structure and on non-radial pulsations. Pulsations are considered possible mechanisms to trigger mass-ejection phenomena required to build up the circumstellar disks of Be stars. Time series analyses of the light curves of 15 faint Be stars observed with the CoRoT satellite were performed to obtain the distribution of non-radial pulsation (NRP) frequencies in their power spectra at epochs with and without light outbursts and to discriminate pulsations from rotation-related photometric variations. Standard Fourier techniques were employed to analyze the CoRoT light curves. Fundamental parameters corrected for rapid-rotation effects were used to study the power spectrum as a function of the stellar location in the instability domains of the Hertzsprung-Russell (H-R) diagram. Frequencies are concentrated in separate groups as predicted for g-modes in rapid B-type rotators, except for the two stars that are outside the H-R instability domain. In five objects the variations in the power spectrum are correlated with the time-dependent outbursts characteristics. Time-frequency analysis showed that during the outbursts the amplitudes of stable main frequencies within 0.03c/d intervals strongly change, while transients and/or frequencies of low amplitude appear separated or not separated from the stellar frequencies. The frequency patterns and activities depend on evolution phases: i) the average separations between groups of frequencies are larger in the zero-age main sequence (ZAMS) than in the terminal age main sequence (TAMS) and are the largest in the middle of the MS phase; ii) a poor frequency spectrum with f<1c/d of low amplitude characterizes the stars beyond the TAMS; and iii) outbursts are seen in stars hotter than B4 spectral type and in the second half of the MS. The two main frequency groups are separated by δf=(1.24±0.28).f{rot} in agreement with models of prograde sectoral g-modes (m=-1,-2) of intermediate-mass rapid rotators. The changes of amplitudes of individual frequencies and the presence of transients correlated with the outburst events deserve further studies of physical conditions in the subatmospheric layers to establish the relationship between pulsations and sporadic mass-ejection events. Description: Tables 7 to 22 contain the frequencies that were derived with the FREQFIND code from the CoRoT light curves of 15 Be stars; some of them were observed in two different runs, while star No 9 was observed in three runs. For each Be star is given the CoRoT number, the number of the star attributed in Paper I (Semaan et al., 2013A&A...551A.130S), the frequency number ordered by increasing value of frequencies, the value of the frequency in c/d (cycle/day), the value of the frequency in micro-Hertz, the amplitude of the frequency in ppm, the phase, the signal to noise ratio (S/N), the order number N_FREQ of the frequency as find by the FREQFIND code, the mark S indicates the 20 frequencies with larger amplitude among which the combinations and harmonics were searched. The combinations and harmonics found are indicated. Each group of frequencies is separated by a horizontal line. File Summary:
FileName Lrecl Records Explanations
ReadMe 80 . This file table1.dat 89 19 Some basic characteristics of the CoRoT data table7.dat 84 74 CoRoT 101486436 data from LRC1 run light curve table8.dat 84 10 CoRoT 102595654 data from LRA1 run light curve table9.dat 84 95 CoRoT 102656190 data from LRA1 run light curve table10.dat 84 48 CoRoT 102672979 data from LRA1 run light curve table11.dat 84 84 CoRoT 102686433 data from LRA1 run light curve table12.dat 140 64 CoRoT 102719279 data from LRA1 run (64 frequencies) and IR1 (24 frequencies) run light curves table13.dat 95 70 CoRoT 102719279 data from LRA1 run (64 frequencies), LRA6 run (42 frequencies) and IR1 run (24 frequencies) light curves table14.dat 93 8 CoRoT 102725623 data from LRA1 run (8 frequencies) and IR1 run (2 frequencies) light curves table15.dat 84 62 CoRoT 102728404 data from LRA1 run light curve table16.dat 140 68 CoRoT 102766835 data from LRA1 run (69 frequencies) and IR1 run (23 frequencies) light curves table17.dat 84 30 CoRoT 102785204 data from LRA1 run light curve table18.dat 84 114 CoRoT 102785480 data from IR1 run light curve table19.dat 84 44 CoRoT 102825808 data from IR1 run light curve table20.dat 84 26 CoRoT 102829773 data from IR1 run light curve table21.dat 84 7 CoRoT 102847615 data from IR1 run light curve table22.dat 84 32 CoRoT 102904910 data from IR1 run light curve
See also: B/corot : CoRoT observation log (N2-4.4) (CoRoT 2016) Byte-by-byte Description of file: table1.dat
Bytes Format Units Label Explanations
1- 5 A5 --- --- [CoRoT] 7- 15 I9 --- CoRoT CoRoT number 17- 18 I2 --- Seq [1/22] Sequential number, as in Paper I (Semaan et al., 2013A&A...551A.130S) 20- 24 F5.2 mag Vmag V magnitude 26- 29 A4 --- Run Run 31- 40 F10.5 d t0 CoRoT time of phase 0 (HJD with origin on 01/01/2000 at 12h00 UT) 42- 47 I6 --- Pts Number of data points 49- 53 A5 --- Sample Sampling: S1=512s, S2=32s 55- 61 F7.3 d DT Total duration of CoRoT observations 63- 68 F6.4 c/d Df Frequency accuracy 70- 72 I3 --- Nf number of identified frequencies 74- 77 I4 ppm Amin lower amplitude detected 79- 89 A11 --- FileName Name of the table with frequencies, amplitudes and phases
Byte-by-byte Description of file: table[789].dat table1[015789].dat table2?.dat
Bytes Format Units Label Explanations
1- 5 A5 --- nr Identification frequencies 6- 7 A2 --- n_nr [p fab] p or f for frequencies with uniform period separation 8- 15 F8.5 c/d Freq Frequency in cycle/day 17- 25 F9.5 uHz FreqHz Frequency in micron-Hertz 27- 31 I5 ppm Amm Amplitude of frequency in ppm 33- 35 F3.1 rad Phase Phase from 0 to 2pi 37- 41 F5.1 --- S/N Signal to noise ratio 43- 45 I3 --- Nfreqfind Frequency order of determination with the FREQFIND code 47 A1 --- Power [S] Indication that the frequency is among the 20th with higher amplitude 49- 84 A36 --- Com Combinations and harmonics
Byte-by-byte Description of file: table12.dat table16.dat
Bytes Format Units Label Explanations
1- 4 A4 --- nr1 Identification frequencies 6- 7 A2 --- n_nr1 [f ab] p or f for frequencies with uniform period separation 9- 15 F7.5 c/d Freq1 ? Frequency in cycle/day 17- 24 F8.5 uHz FreqHz1 ? Frequency in micron-Hertz 26- 30 I5 ppm Amm1 ? Amplitude of frequency in ppm 32- 34 F3.1 rad Phase1 ? Phase from 0 to 2pi 36- 39 F4.1 --- S/N1 ? Signal to noise ratio 41- 42 I2 --- Nfreqfind1 ? Frequency order of determination with the FREQFIND code 44 A1 --- Power1 [S] Indication that the frequency is among the 20th with higher amplitude 46- 76 A31 --- Com1 Combinations and harmonics 78- 81 A4 --- nr2 Identification frequencies 83- 89 F7.5 c/d Freq2 ? Frequency in cycle/day 91- 98 F8.5 uHz FreqHz2 ? Frequency in micron-Hertz 100-104 I5 ppm Amm2 ? Amplitude of frequency in ppm 106-108 F3.1 rad Phase2 ? Phase from 0 to 2pi 110-113 F4.1 --- S/N2 ? Signal to noise ratio 115-116 I2 --- Nfreqfind2 ? Frequency order of determination with the FREQFIND code 118 A1 --- Power2 [S] Indication that the frequency is among the 20th with higher amplitude 120-140 A21 --- Com2 Combinations and harmonics
Byte-by-byte Description of file: table13.dat
Bytes Format Units Label Explanations
1- 4 A4 --- nr1 Identification frequencies 6- 12 F7.5 c/d Freq1 ? Frequency in cycle/day 14- 17 A4 --- nr2 Identification frequencies 19- 25 F7.5 c/d Freq2 ? Frequency in cycle/day 27- 34 F8.5 uHz FreqHz2 ? Frequency in micron-Hertz 36- 39 I4 ppm Amm2 ? Amplitude of frequency in ppm 41- 43 F3.1 rad Phase2 ? Phase from 0 to 2pi 45- 48 F4.1 --- S/N2 ? Signal to noise ratio 50- 51 I2 --- Nfreqfind2 ? Frequency order of determination 53- 56 A4 --- nr3 Identification frequencies 58- 64 F7.5 c/d Freq3 ? Frequency in cycle/day 66- 95 A30 --- Com Combinations and harmonics
Byte-by-byte Description of file: table14.dat
Bytes Format Units Label Explanations
1- 3 A3 --- nr1 Identification frequencies 5- 11 F7.5 c/d Freq1 Frequency in cycle/day 13- 20 F8.5 uHz FreqHz1 Frequency in micron-Hertz 22- 24 I3 ppm Amm1 Amplitude of frequency in ppm 26- 28 F3.1 rad Phase1 Phase from 0 to 2pi 30- 32 F3.1 --- S/N1 Signal to noise ratio 34 I1 --- Nfreqfind1 Frequency order of determination with the FREQFIND code 36 A1 --- Power1 [S] Indication that the frequency is among the 20th with higher amplitude 38- 45 A8 --- Com1 Combinations and harmonics 47- 49 A3 --- nr2 Identification frequencies 51- 57 F7.5 c/d Freq2 ? Frequency in cycle/day 59- 66 F8.5 uHz FreqHz2 ? Frequency in micron-Hertz 68- 70 I3 ppm Amm2 ? Amplitude of frequency in ppm 72- 74 F3.1 rad Phase2 ? Phase from 0 to 2pi 76- 78 F3.1 --- S/N2 ? Signal to noise ratio 80 I1 --- Nfreqfind2 ? Frequency order of determination with the FREQFIND code 82 A1 --- Power2 [S] Indication that the frequency is among the 20th with higher amplitude 84- 93 A10 --- Com2 Combinations and harmonics
Acknowledgements: Thierry Semann, thierry.semaan(at)unige.ch References: Semaan et al., Paper I 2013A&A...551A.130S
(End) Thierry Semann [Geneve univ.], Patricia Vannier [CDS] 01-Feb-2018
The document above follows the rules of the Standard Description for Astronomical Catalogues.From this documentation it is possible to generate f77 program to load files into arrays or line by line

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