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J/A+A/308/481      Metallic line doubling phenomenon in RR Lyrae (Chadid+, 1996)

Observation of the metallic line doubling phenomenon in the variable star RR Lyrae. Chadid M., Gillet D. <Astron. Astrophys. 308, 481 (1996)> =1996A&A...308..481C (SIMBAD/NED BibCode)
ADC_Keywords: Line Profiles ; Stars, variable Keywords: hydrodynamics - shock waves - stars: pulsation - stars: individual: RR Lyrae Description: For the first time, the observation of the line doubling phenomenon over two metallic absorption lines of a RR Lyrae star (RR Lyr) is reported. A resolving power of 42,000 and a time resolution close to 1% of the pulsating period were necessary. Although a smaller exposure time would be required to completely resolve this phenomenon over the whole spectrum, we interpret it as the consequence of a "two-step" Schwarzschild's mechanism. Thus a strong shock wave propagating throughout the photosphere around phase 0.93 would be at the origin of the observed line doubling. Because the shock undergoes a sudden acceleration phase, a "jump" appears in the line profile evolution. The shock is first receding and then almost stationary. Our qualitative interpretation needs a theoretical confirmation with the help of a nonlinear nonadiabatic pulsational model with an extended atmosphere taking into account the presence of shock waves. Nevertheless it appears from our observations that the dynamics of the atmosphere of RR Lyr is important just above the photosphere and that strong shock exists at this level because the doubling is already present in FeI lines. Ojects: ------------------------------------------ RA (2000) DE Name ------------------------------------------ 19 25 28.3 +42 47 14 RR Lyr = HD 182989 ------------------------------------------ File Summary:
FileName Lrecl Records Explanations
ReadMe 80 . This file table1 52 92 *Journal of the spectrovelocimetric observations of RR Lyr
Note on table1: this table corresponds to table1 and table2 of the printed version
Byte-by-byte Description of file: table1
Bytes Format Units Label Explanations
2- 8 F7.3 --- Phi Phase (1) 10- 22 F13.4 d JD Julian Date 24- 26 I3 s Time Exposure time 28- 29 I2 --- S/N Signal to noise ratio 31- 38 F8.3 km/s HRV Heliocentric radial velocity 40- 45 F6.3 km/s Sigma FWHM/2.35 of the line 47- 52 F6.4 --- Amp Line deep
Note (1): According to the ephemeris: HJD (maximum brightness) = 2444003.8537 + 0.566839*E.

(End) Simona Mei [CDS] 18-Sep-1995
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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