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J/MNRAS/463/1332     Anomalous RRd stars in Magellanic Clouds (Soszynski+, 2016)

Anomalous double-mode RR Lyrae stars in the Magellanic Clouds. Soszynski I., Smolec R., Dziembowski W.A., Udalski A., Szymanski M.K., Wyrzykowski L., Ulaczyk K., Poleski R., Pietrukowicz P., Kozlowski S., Skowron D., Skowron J., Mroz P., Pawlak M. <Mon. Not. R. Astron. Soc., 463, 1332-1341 (2016)> =2016MNRAS.463.1332S (SIMBAD/NED BibCode)
ADC_Keywords: Magellanic Clouds ; Stars, variable ; Asteroseismology Keywords: stars: oscillations - stars: variables: RR Lyrae - Magellanic Clouds Abstract: We report the discovery of a new subclass of double-mode RR Lyrae stars in the Large and Small Magellanic Clouds. The sample of 22 pulsating stars has been extracted from the latest edition of the Optical Gravitational Lensing Experiment collection of RR Lyrae variables in the Magellanic System. The stars pulsating simultaneously in the fundamental (F) and first-overtone (1O) modes have distinctly different properties than regular double-mode RR Lyrae variables (RRd stars). The P1O/PF period ratios of our anomalous RRd stars are within a range of 0.725-0.738, while 'classical' double-mode RR Lyrae variables have period ratios in the range of 0.742-0.748. In contrast to the typical RRd stars, in the majority of the anomalous pulsators, the F-mode amplitudes are higher than the 1O-mode amplitudes. The light curves associated with the F-mode in the anomalous RRd stars show different morphology than the light curves of, both, regular RRd stars and single-mode RRab stars. Most of the anomalous double-mode stars show long-term modulations of the amplitudes (Blazhko-like effect). Translating the period ratios into the abundance parameter, Z, we find for our stars Z∈(0.002, 0.005) - an order of magnitude higher values than typical for RR Lyrae stars. The mass range of the RRd stars inferred from the WI versus PF diagram is (0.55-0.75)M. These parameters cannot be accounted for with single star evolution assuming a Reimers-like mass-loss. Much greater mass-loss caused by interaction with other stars is postulated. We blame the peculiar pulsation properties of our stars to the parametric resonance instability of the 1O-mode to excitation of the F- and 2O-modes as with the inferred parameters of the stars 2ω1O~=ωF2O. Description: The sample of anomalous RRd stars has been extracted from the OGLE collection of 45451 RR Lyrae variables in the Magellanic Clouds (Soszyski et al., 2016AcA....66..131S). File Summary:
FileName Lrecl Records Explanations
ReadMe 80 . This file table1.dat 70 22 Basic properties of anomalous RRd stars tablea.dat 81 133 Identifications of all detected frequencies (tables A1-A22 of the paper)
Byte-by-byte Description of file: table1.dat
Bytes Format Units Label Explanations
1- 20 A20 --- Name Star name 22- 29 F8.6 d P1O 1O mode period 31- 38 F8.6 d PF F mode period 40- 45 F6.4 --- F1O/PF P1O/PF period ratio 47- 51 F5.3 mag AF Fourier amplitude of the fundamental mode 53- 56 F4.2 --- A1O/AF A1O/AF amplitude ratio 58- 63 F6.3 mag <Imag> Mean I-band magnitude 65- 70 F6.3 mag <Vmag> ? Mean V-band magnitude
Byte-by-byte Description of file: tablea.dat
Bytes Format Units Label Explanations
1- 20 A20 --- Name Star name 22- 41 A20 --- FreqID Frequency identification 44- 51 F8.6 d-1 Freq Frequency 54- 60 F7.6 d-1 e_Freq ? rms uncertainty on Freq 64- 66 I3 mmag A ? Amplitude 68 I1 mmag e_A ? rms uncertainty on A 70- 73 F4.2 rad phi ? Phase 75- 78 F4.2 rad e_phi ? rms uncertainty on rad 80- 81 A2 --- Rem [bl ] Remarks (1)
Note (1): bl indicates a frequency of the Blazhko modulation, In case no significant peak was detected in the frequency spectrum directly at ν=νm. Amplitude and phase are not given then.
History: From electronic version of the journal
(End) Patricia Vannier [CDS] 03-May-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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