J/ApJS/213/31 Blazhko effect from 4yr of Kepler data (Benko+, 2014)
Long-timescale behavior of the Blazhko effect from rectified Kepler data.
Benko J.M., Plachy E., Szabo R., Molnar L., Kollath Z.
<Astrophys. J. Suppl. Ser., 213, 31 (2014)>
=2014ApJS..213...31B 2014ApJS..213...31B
ADC_Keywords: Stars, variable ; Photometry
Keywords: space vehicles; stars: oscillations; stars: variables: RR Lyrae;
techniques: photometric
Abstract:
In order to benefit from the four year unprecedented precision of the
Kepler data, we extracted light curves from the pixel photometric data
of the Kepler space telescope for 15 Blazhko RR Lyrae stars. To
collect all the flux from a given target as accurately as possible, we
defined tailor-made apertures for each star and quarter. In some
cases, the aperture finding process yielded sub-optimal results,
because some flux have been lost even if the aperture contains all
available pixels around the star. This fact stresses the importance of
those methods that rely on the whole light curve instead of focusing
on the extrema (O-C diagrams and other amplitude independent methods).
We carried out detailed Fourier analysis of the light curves and the
amplitude independent O-C diagram. We found 12 (80%) multiperiodically
modulated stars in our sample. This ratio is much higher than
previously found. Resonant coupling between radial modes, a recent
theory for explaining the Blazhko effect, allows single,
multiperiodic, or even chaotic modulations. Among the stars with two
modulations, we found three stars (V355 Lyr, V366 Lyr, and V450 Lyr)
where one of the periods dominates in amplitude modulation, but the
other period has a larger frequency modulation amplitude. The ratio
between the primary and secondary modulation periods is almost always
very close to the ratios of small integer numbers. It may indicate the
effect of undiscovered resonances. Furthermore, we detected the
excitation of the second radial overtone mode f2 for three stars
where this feature was formerly unknown. Our data set comprises the
longest continuous, most precise observations of Blazhko RR Lyrae
stars ever published. These data are made publicly available and will
be unrivaled for years to come.
Description:
The Kepler commissioning phase data (Q0) between 2009 May 2 to 11
(9.7 days) included only one Blazhko star: KIC 11125706. The
observations of other targets began with Q1 on 2009 May 13. Here we
analyzed light curve (LC) data to the end of the last full quarter
(Q16, until 2013 April 8). The total length of the data covers 3.9yr.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 88 771858 Rectified Kepler data for the 15 Blazhko stars
table3.dat 88 15 Basic properties of the Kepler Blazhko stars
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See also:
B/gcvs : General Catalogue of Variable Stars (Samus+ 2007-2013)
V/133 : Kepler Input Catalog (Kepler Mission Team, 2009)
II/264 : ASAS Variable Stars in Southern hemisphere (Pojmanski+, 2002-2005)
J/A+A/562/A90 : Times of maximum light of Blazhko RRab stars (Skarka, 2014)
J/A+A/549/A101 : Known Galactic field Blazhko stars (Skarka, 2013)
J/AJ/144/39 : RRab stars from the GEOS RR Lyr Survey (Le Borgne+, 2012)
J/MNRAS/427/1517 : XY And and UZ Vir light curves (Sodor+, 2012)
J/MNRAS/420/1333 : NGC 5024 RR Lyrae VI light curves (Arellano Ferro+, 2012)
J/MNRAS/415/1577 : CoRoT 105288363 Blazhko modulation (Guggenberger+, 2011)
J/MNRAS/411/1585 : CZ Lac multiperiodic Blazhko modulation (Sodor+, 2011)
J/A+A/510/A39 : CoRoT light curves of V1127 Aql (Chadid+, 2010)
J/A+A/454/257 : First overtone RR Lyrae in LMC (Nagy+, 2006)
Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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1- 8 I8 --- KIC Kepler Input Catalog identifier (1)
10- 18 A9 --- GCVS General Catalog of Variable Stars identifier
20- 23 I4 --- Num [1/4588] Serial number (1)
25- 36 F12.7 d BJD Barycentric Julian Date; -2454833.0
38- 45 F8.1 ct/s SFlux [1192.2/351159] Flux summed up in a tailor-made
aperture; e-/s
47- 54 F8.2 ct/s ZPO [-2302/1922] Zero point offset; e-/s
56- 60 F5.3 --- Scl [0.8/1.2] Scaling factor; 1 = no scaling
62- 76 F15.8 ct/s CFlux [1190/350500] Shifted, scaled & detrended flux;
in e-/s
78- 88 F11.8 mag Kpmag [-0.9/0.5] The CFlux value in Kepler magnitude
scale
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Note (1): Individual source information.
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KIC Stepsize Boxcars width Factor of the sigma
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3864443 0.0500016515 214.9571 500.
4484128 0.0500016534 34.9511557 500.
5559631 0.0500016568 44.9514895 500.
6183128 0.0500016603 152.955079 500.
6186029 0.0500016599 152.955078 500.
7257008 0.0500033496 49.9533463 500.
7505345 0.0500016097 504.966256 500.
7671081 0.0500016651 504.966816 500.
9001926 0.0500016713 504.966879 500.
9578833 0.0500016737 44.9515047 500.
9697825 0.0500016742 44.9515051 500.
9973633 0.0500033519 6.95046591 500.
10789273 0.0500016796 246.958296 500.
11125706 0.0500010355 149.953105 500.
12155928 0.0500016873 149.95506 500.
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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- 8 I8 --- KIC KIC number (Cat. V/133)
10- 18 A9 --- GCVS General Catalog of Variable Stars identifier
20- 28 F9.7 d Per0 [0.4/0.7] Pulsation period (P0)
30- 35 F6.4 mag A(f0) [0.1/0.4] Fourier amplitude of the main
pulsation frequency
37- 44 F8.4 d PerB [27/849] Primary modulation period (PB)
46- 52 F7.4 d e_PerB [0.0005/59] PerB uncertainty
54 A1 --- l_PerS [≳? ] Limit or uncertainty flag on PerS
56- 62 F7.2 d PerS [16/1000]? Secondary modulation period (PS)
64- 67 F4.2 d e_PerS [0.01/2]? PerS uncertainty
69- 80 A12 --- Freq Additional frequencies (1)
82- 88 A7 --- Rk Remarks (2)
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Note (1): The pattern of additional frequencies are
(brackets indicate marginal effects):
PD = period doubling;
F1 = first overtone frequency and its linear combination
with the fundamental one;
F2 = as F1, but with the second radial overtone;
F' = frequencies with unidentified modes;
Note (2): Remarks as follows:
scal = scaled,
m = missing quarters,
Q10- = data from Q10.
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History:
From electronic version of the journal
(End) Greg Schwarz [AAS], Emmanuelle Perret [CDS] 11-Sep-2014