J/A+A/449/305 Geneva photometry time series of HD 203664 (Aerts+, 2006)
Multiperiodicity in the large-amplitude rapidly-rotating beta Cephei star
HD 203664.
Aerts C., De Cat P., De Ridder J., Van Winckel H., Raskin G.,
Davignon G., Uytterhoeven K.
<Astron. Astrophys. 449, 305 (2006)>
=2006A&A...449..305A 2006A&A...449..305A
ADC_Keywords: Stars, early-type ; Stars, variable ; Photometry, Geneva
Keywords: stars: oscillations - stars: variables: general - stars: early-type -
stars: individual: HD 203664 - stars: interiors
Abstract:
We made a seismic study of the young massive beta Cephei star
HD 203664 with the goal of constraining its interior structure. Our
study is based on a time series of 328 new Geneva 7-colour photometric
data of the star spread over 496.8 days. The data confirm the
frequency of the dominant mode of the star, which we refined to
f1=6.02885c/d. The mode has a large amplitude of 37mmag in V and is
unambiguously identified as a dipole mode (l=2) from its amplitude
ratios and non-adiabatic computations. Besides f1, we discovered two
additional new frequencies in the star with amplitudes above 4σ:
f2=6.82902c/d and f3=4.81543c/d, or one of their daily aliases.
The amplitudes of these two modes are only between 3 and 4mmag, which
explains why they were not detected before. Their amplitude ratios are
too uncertain for mode identification. We show that the observed
oscillation spectrum of HD 203664 is compatible with standard stellar
models but that we have insufficient information for asteroseismic
inferences. Among the large-amplitude beta Cephei stars, HD 203664
stands out as the only one rotating at a significant fraction of its
critical rotation velocity (∼40%).
Description:
Time series of seven colour Geneva photometry in the filters U B1 B B2
V1 V G of the star HD 203664
Objects:
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RA (2000) DE Designation(s)
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21 23 28.8 +09 55 55 HD 203664 = V* SY Equ
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File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 68 328 Time series
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Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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1- 13 F13.5 d HJD Heliocentric Julian Date of mid exposure
16- 20 F5.3 mag Umag Geneva U magnitude
24- 28 F5.3 mag B1mag Geneva B1 magnitude
32- 36 F5.3 mag Bmag Geneva B magnitude
40- 44 F5.3 mag B2mag Geneva B2 magnitude
48- 52 F5.3 mag V1mag Geneva V1 magnitude
56- 60 F5.3 mag Vmag Geneva V magnitude
64- 68 F5.3 mag Gmag Geneva G magnitude
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Acknowledgements: Conny Aerts, conny(at)ster.kuleuven.be
(End) Patricia Vannier [CDS] 01-Dec-2005