J/A+A/413/293 Radial velocities of RZ Cas (Lehmann+, 2004)
The eclipsing binary star RZ Cas.
I. First spectroscopic detection of rapid pulsations in an Algol system.
Lehmann H., Mkrtichian D.E.
<Astron. Astrophys., 413, 293-299 (2004)>
=2004A&A...413..293L 2004A&A...413..293L
ADC_Keywords: Binaries, eclipsing ; Binaries, spectroscopic ; Radial velocities
Keywords: stars: binaries: eclipsing: variables: oscillations -
stars: individual: RZ Cas
Abstract:
In a first report on the results of a multi-site campaign in 2001 of
photometric and spectroscopic observations of the active
semi-detached Algol-type system RZ Cas, we concentrate on the radial
velocity (RV) variations. Using weak absorption lines we obtain an
improved orbital solution for both components. In the orbital RV curve
we observe a strong, asymmetric rotation effect. For the first time we
detect rapid spectroscopic multi-mode pulsations in an Algol system.
Whereas the photometrically observed oscillations were dominated by
monoperiodic pulsations at frequency 64.19c/d until the year 2000, we
find in 2001 a multiperiodic behaviour with two dominant frequencies
of f1=56.600c/d and f2=64.189c/d. Both modes show amplitude variations
over the orbital phase with a minimum at orbital phases phi=0.6-0.8
and a maximum just after the primary minimum (f2) and at phi=0.25
(f1). The different shape of amplitude modulation of the f1 and f2
modes points to different (l,m) mode structures.
The modulation itself can be explained by assuming a variable
extinction due to gas streams and an inhomogeneous accretion annulus
that weakens the light from different regions of the primary depending
on its orbital position.
Description:
Heliocentric radial velocities (RVs) for the primary and secondary
components of the eclipsing binary RZ Cas are presented. RVs of the
primary are derived from a cross-correlation of metallic lines in the
range 4970 to 5550 Angstroem. RVs of the secondary are measured from
Gaussian fits to the five strongest metal lines of the secondary which
are Ca I (6103, 6122 Angstroem) and Fe I (4957, 5616, 5659 Angstroem).
For the primary we also list the Hα and Hβ RVs derived from
line profile fitting. RV values are given only for lines from spectra
with sufficiently high S/N (for the secondary, mainly from
outside-the-eclipses spectra). Error values of 0.000 indicate missing
measurements.
Objects:
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RA (2000) DE Designation(s)
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02 48 55.5 +69 38 03 RZ Cas = HD 17138
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File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table3.dat 85 960 Radial velocities
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Byte-by-byte Description of file: table3.dat
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Bytes Format Units Label Explanations
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1- 13 F13.5 --- HJD Heliocentric Julian date
15- 22 F8.3 km/s HRVm1 Radial velocity from metallic lines (primary)
24- 31 F8.3 km/s e_HRVm1 ?=0.00 Error of HRV1m (error = 0 => unknown)
33- 40 F8.3 km/s HRVm2 Radial velocity from metallic lines (secondary)
42- 49 F8.3 km/s e_HRVm2 ?=0.00 Error of HRV2m (error = 0 => unknown)
51- 58 F8.3 km/s HRVa1 Radial velocity from Halpha (primary)
60- 67 F8.3 km/s e_HRVa1 ?=0.00 Error of HRV1a (error = 0 => unknown)
69- 76 F8.3 km/s HRVb1 Radial velocity from Hbeta (primary)
78- 85 F8.3 km/s e_HRVb1 ?=0.00 Error of HRV1b (error = 0 => unknown)
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Acknowledgements:
Holger Lehmann
(End) Holger Lehmann [TLS, Germany] 05-Jan-2004