J/MNRAS/469/3802 Compact binary systems around Kepler red giants (Colman+, 2017)
Evidence for compact binary systems around Kepler red giants.
Colman I.L., Huber D., Bedding T.R., Kuszlewicz J.S., Yu J., Beck P.G.,
Elsworth Y., Garcia R.A., Kawaler S.D., Mathur S., Stello D., White T.R.
<Mon. Not. R. Astron. Soc., 469, 3802-3812 (2017)>
=2017MNRAS.469.3802C 2017MNRAS.469.3802C (SIMBAD/NED BibCode)
ADC_Keywords: Stars, double and multiple ; Stars, giant ; Asteroseismology
Keywords: binaries: close - stars: oscillations
Abstract:
We present an analysis of 168 oscillating red giants from NASA's
Kepler mission that exhibit anomalous peaks in their Fourier amplitude
spectra. These peaks result from ellipsoidal variations that are
indicative of binary star systems, at frequencies such that the orbit
of any stellar companion would be within the convective envelope of
the red giant. Alternatively, the observed phenomenon may be due to a
close binary orbiting a red giant in a triple system, or chance
alignments of foreground or background binary systems contaminating
the target pixel aperture. We identify 87 stars in the sample as
chance alignments using a combination of pixel Fourier analysis and
difference imaging. We find that in the remaining 81 cases, the
anomalous peaks are indistinguishable from the target star to within 4
arcsec, suggesting a physical association. We examine a GALAXIA model
of the Kepler field of view to estimate background star counts and
find that it is highly unlikely that all targets can be explained by
chance alignments. From this, we conclude that these stars may
comprise a population of physically associated systems.
Description:
The 168 stars studied were all discovered among Kepler red giants by
visual inspection of power spectra. Many were included in the samples
of Huber et al. (2010ApJ...723.1607H 2010ApJ...723.1607H, 2011ApJ...743..143H 2011ApJ...743..143H) or Stello
et al. (2013, Cat. J/ApJ/765/L41). Additional stars were taken from Yu
et al. (2017MNRAS.465.1297H 2017MNRAS.465.1297H) or found in the APOKASC sample
(Pinsonneault et al., 2014, Cat. J/ApJS/215/19).
We found that, of the 168 red giants with anomalous peaks, 87 could be
identified as chance alignments, listed in Table 1. For 19 of these
chance alignments, listed in Table 2, we confirmed their status with
the analysis of Kepler light curves of nearby stars which we
identified as the sources of contamination. We could not spatially
resolve the 81 other stars (Table 3), and we refer to these as
possibly associated systems.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 72 68 Details of the 68 presumed chance alignments
table2.dat 81 19 Details of the 19 confirmed chance alignments
with a known entry in the KIC
table3.dat 72 81 *Details of the 81 possible physical associations
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Note on table3.dat: Stellar parameters are taken from the NASA Exoplanet
Archive, data release 25 (Mathur et al., 2017, Cat. J/ApJS/229/30).
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See also:
V/133 : Kepler Input Catalog (Kepler Mission Team, 2009)
J/ApJ/765/L41 : Asteroseismic classification of KIC objects (Stello+, 2013)
J/ApJS/215/19 : APOKASC catalog of Kepler red giants (Pinsonneault+, 2014)
J/ApJS/229/30 : Revised stellar properties of Q1-17 Kepler targets
(Mathur+, 2017)
Byte-by-byte Description of file: table1.dat table2.dat table3.dat
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Bytes Format Units Label Explanations
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1- 8 I8 --- KIC KIC number
10- 20 F11.7 deg RAdeg Right ascension (J2000)
22- 30 F9.6 deg DEdeg Declination (J2000)
32- 36 F5.2 [cm/s2] log(g) Surface gravity
38- 41 F4.2 mag Kpmag Kepler magnitude
43- 46 I4 K Teff Effective temperature
48- 52 F5.2 [-] [Fe/H] Metallicity
54- 59 F6.2 uHz numax Frequency at maximum
61 A1 --- n_nupeak [+*] Note on nupeak (1)
62- 67 F6.2 uHz nupeak Peak frequency
69- 72 F4.2 d Ppeak Peak period
74- 81 I8 --- Cont ? Contaminated KIC number (only in table2)
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Note (1): Notes as follows:
* = anomalous peak to be part of δ Scuti oscillations
+ = anomalous peak to be part of γ Doradus oscillations
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History:
From electronic version of the journal
(End) Patricia Vannier [CDS] 16-Apr-2020