J/ApJS/224/37 White-light flares on close binaries from Kepler (Gao+, 2016)
White-light flares on close binaries observed with Kepler.
Gao Q., Xin Y., Liu J.-F., Zhang X.-B., Gao S.
<Astrophys. J. Suppl. Ser., 224, 37-37 (2016)>
=2016ApJS..224...37G 2016ApJS..224...37G (SIMBAD/NED BibCode)
ADC_Keywords: Stars, flare ; Stars, double and multiple ; Binaries, eclipsing
Keywords: binaries: close; stars: activity; stars: flare
Abstract:
Based on Kepler data, we present the results of a search for white
light flares on 1049 close binaries. We identify 234 flare binaries,
of which 6818 flares are detected. We compare the flare-binary
fraction in different binary morphologies ("detachedness"). The
result shows that the fractions in over-contact and ellipsoidal
binaries are approximately 10%-20% lower than those in detached and
semi-detached systems. We calculate the binary flare activity level
(AL) of all the flare binaries, and discuss its variations along the
orbital period (Porb) and rotation period (Prot, calculated for
only detached binaries). We find that the AL increases with decreasing
Porb or Prot, up to the critical values at Porb∼3 days or
Prot∼1.5 days, and thereafter the AL starts decreasing no matter how
fast the stars rotate. We examine the flaring rate as a function of
orbital phase in two eclipsing binaries on which a large number of
flares are detected. It appears that there is no correlation between
flaring rate and orbital phase in these two binaries. In contrast,
when we examine the function with 203 flares on 20 non-eclipse
ellipsoidal binaries, bimodal distribution of amplitude-weighted flare
numbers shows up at orbital phases 0.25 and 0.75. Such variation could
be larger than what is expected from the cross section modification.
Description:
The Kepler spacecraft was launched by NASA in 2009 March. The typical
photometry precision is 0.1mmag for a star of 12mag, and the
photometry was continuously processed and recorded for a period of
four years.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 69 234 Fundamental parameters of 234 flare binaries
table2.dat 48 6815 Parameters of the flares
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See also:
V/133 : Kepler Input Catalog (Kepler Mission Team, 2009)
J/ApJS/224/12 : Kepler planetary candidates. VII. 48-month (Coughlin+, 2016)
J/MNRAS/447/2714 : Flare stars across the H-R diagram (Balona+, 2015)
J/ApJS/211/2 : Revised properties of Q1-16 Kepler targets (Huber+, 2014)
J/MNRAS/437/3473 : Temperatures of Kepler eclipsing binaries (Armstrong+, 2014)
J/PASP/126/914 : Kepler eclipsing binary stars. V. (Conroy+, 2014)
J/AJ/147/45 : Kepler mission. IV. Close binaries (Conroy+, 2014)
J/ApJS/209/5 : Superflares of Kepler stars. I. (Shibayama+, 2013)
J/A+A/557/L10 : Rotation periods of 12000 Kepler stars (Nielsen+, 2013)
J/MNRAS/431/2240 : Activity in A-type stars from Kepler (Balona, 2013)
J/MNRAS/428/1656 : Time of minima of HD 181068 (Borkovits+, 2013)
J/other/Nat/485.478 : Superflares on solar-type stars (Maehara+, 2012)
J/ApJ/728/117 : Kepler planetary candidates. I. (Borucki+, 2011)
J/AJ/142/160 : Kepler Mission. II. eclipsing binaries (Slawson+, 2011)
J/AJ/141/50 : White-light flares on stars from Kepler (Walkowicz+, 2011)
J/A+A/529/A89 : Kepler satellite variability study (Debosscher+, 2011)
http://archive.stsci.edu/kepler/ : MAST Kepler home page
http://keplerebs.villanova.edu/ : Kepler Eclipsing Binaries online catalog
Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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1 I1 --- --- [0]
2- 9 I08 --- KIC Kepler Input Catalog identifier
11- 14 I4 K Teff [3354/9981] Effective Temperature, from KIC
16- 20 F5.3 cm/s2 logg [2.4/5.1] Surface Gravity, from KIC
22- 28 F7.3 d Porb [0.4/570] Orbital period (1)
30- 33 F4.2 --- c [0/1] Morphology value (1) (2)
35- 39 F5.3 mag Amp [0.001/0.3] Light curve amplitude (1)
41- 49 E9.3 --- AL Flare activity level (3)
51- 55 F5.3 d-1 f [0.001/0.3] Flare Frequency (f(flares/day))
57- 59 I3 --- Nf [1/345] Total number of flares
61- 66 F6.3 [-] dF/F [-3.3/-0.2] Log Relative flare intensity (4)
68- 69 I2 --- Notes [21/24] Kepler LC-PDC data release version
adopted for each flare binary (5)
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Note (1): From the Kepler eclipsing binary (KEB) catalog,
Kirk et al. 2016, J/AJ/151/68.
Note (2): Morphology of binaries:
detached = c≲0.5
semi-detached = 0.5≲c≲0.7
over-contact = 0.7≲c≲0.8
ellipsoidal = c≳0.8
See section 3.2 and figure 7 for more explanations.
Note (3): For one binary system, the summation of the equivalent widths (EWs)
of all the flares divided by the total observation time can provide a
measurement of the flaring intensity, which is defined as the flare
"activity leve" (AL) in the work as in Equation (3):
AL=(ΣNfi=1EWi)/Tobs∼Ef/Eq
where EWi is the EW of the ith observed flare on a binary.
Tobs is the entire observation time of the binary.
Eq is the total energy of the quiescent radiation and
Ef is the total energy of all the flares.
See section 3 for further explanations.
Note (4): The peak relative flux of flares (log({ΔFmax/{bar}F)) are
calculated in the work. ΔFmax is calculated by substituting
F of the highest energy flare into Equation (1).
Note (5): There are different release versions of the Kepler LC-PDC data.
See http://archive.stsci.edu/kepler/data_release.html for the release
notes.
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Byte-by-byte Description of file: table2.dat
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Bytes Format Units Label Explanations
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1 I1 --- --- [0]
2- 9 I08 --- KIC Kepler Input Catalog identifier
11- 20 F10.5 d BJD Barycentric Julian date for each mean flare time;
BJD-2450000
22- 29 F8.6 d EW [0/0.11] Total integrated flux of the flare (1)
31- 38 F8.6 --- dF/F [0.0001/0.9] Relative flare intensity
40- 48 F9.6 h dt [0.9/34] Total flare duration
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Note (1): For each flare, we integrate the points that are tagged as part of
the flare, which is essentially a photometric equivalent width (EW)
of the flare (Walkowicz et al. 2011, J/AJ/141/50), i.e.,
Equation (2): EW=∫((Ff-Fq)/Fq)dt
where Ff and Fq are the flaring and the quiescent flux,
respectively. See section 3.
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History:
From electronic version of the journal
(End) Prepared by [AAS], Emmanuelle Perret [CDS] 20-Jul-2016