J/A+A/549/A104 Spectroscopy of δ Scuti star KIC 5988140 (Lampens+, 2013)
Low-frequency variations of unknown origin in the Kepler delta Scuti star
KIC 5988140 = HD 188774.
Lampens P., Tkachenko A., Lehmann H., Debosscher J., Aerts C., Beck P.G.,
Bloemen S., Kochiashvili N., Derekas A., Smith J.C., Tenenbaum P.,
Twicken J.D.
<Astron. Astrophys. 549, A104 (2013)>
=2013A&A...549A.104L 2013A&A...549A.104L
ADC_Keywords: Stars, variable ; Radial velocities ; Spectroscopy
Keywords: asteroseismology - stars: variable: delta Scuti -
stars: atmospheres - stars: abundances - stars: rotation -
stars: individual: HD 188774
Abstract:
We used high-quality Kepler photometry and spectroscopic data to
investigate the Kepler binary candidate KIC 5988140. Using the
spectrum synthesis method, we derived the fundamental parameters
(Teff, logg, [M/H], vsini) and the abundances. Frequency analyses
of both the photometric and the spectroscopic data revealed the same
two dominant frequencies. We also detected in the photometry the
signal of nine more, significant frequencies located in the range
10-15c/d. The light and radial velocity curves follow a similar,
stable double-wave pattern.
We considered three different scenarios: binarity, co-existence of
Gamma Doradus and Delta Scuti pulsations and rotational modulation. We
confirm the occurrence of various independent Delta Scuti-type
pressure modes in the Kepler light curve. However, we argue that the
physical cause of low frequencies in the light and radial velocity
variations of this late A-type star remain unexplained by any of the
presently considered scenarios.
Description:
A total of 40 optical spectra taken in 2010 with the HERMES
spectrograph attached to the 1.2-m Mercator telescope (Observatorio
del Roque de los Muchachos, Spain) in the range 380-900nm and in 2011
with the Coude-Echelle spectrograph attached to the 2-m telescope at
the Thueringer Landessternwarte Tautenburg (Germany) in the range
472-740nm is being presented. The spectra were reduced by automated
and standard data reduction pipeline including cosmic ray,
heliocentric and telluric corrections as well as normalization to the
local continuum.
Objects:
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RA (2000) DE Designation(s)
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19 55 10.04 +41 17 10.3 HD 188774 = KIC 5988140
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File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
tablea1.dat 54 40 List of collected spectra
sp/* . 40 Individual spectra
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Byte-by-byte Description of file: tablea1.dat
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Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 2 I2 --- Seq Sequence number
6- 9 I4 s ExpTime Exposure time
12- 21 A10 "YYYY/MM/DD" Date Observation date (2010June to 2011Sep)
25- 35 F11.7 d BJD Barycentric Julian Date (BJD-2455000)
39- 50 A12 --- FileName Name of the spectrum in subdirectory sp
54 A1 --- Inst [1/2] Instrument code (1)
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Note (1): Code as follows:
1 = HERMES spectrograph attached to the 1.2-m Mercator telescope
(Observatorio del Roque de los Muchachos, La Palma, Canary Island)
2 = TLS coude-Echelle spectrograph attached to the 2-m telescope at
the Thuringer Landessternwarte Tautenburg
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Byte-by-byte Description of file: sp/*
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Bytes Format Units Label Explanations
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1- 11 F11.6 0.1nm lambda [3764/9007] Wavelength λ (Å)
16- 23 F8.6 --- Flux Flux (normalized to local continuum)
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Acknowledgements:
Patricia Lampens, patricia.lampens(at)oma.be
(End) Patricia Lampens [Belgium Royal Obs.], Patricia Vannier [CDS] 13-Nov-2012