J/AJ/157/171 Visual analysis and demographics of Kepler TTVs (Kane+, 2019)
Visual analysis and demographics of Kepler transit timing variations.
Kane M., Ragozzine D., Flowers X., Holczer T., Mazeh T., Relles H.M.
<Astron. J., 157, 171 (2019)>
=2019AJ....157..171K 2019AJ....157..171K (SIMBAD/NED BibCode)
ADC_Keywords: Binaries, eclipsing ; Exoplanets ; Stars, diameters ;
Effective temperatures ; Stars, masses ; Magnitudes
Keywords: planetary systems -
planets and satellites: dynamical evolution and stability
Abstract:
We visually analyzed the transit timing variation (TTV) data of 5930 Kepler
Objects of Interest (KOIs) homogeneously. Using data from Rowe et al.
(2014, J/ApJ/784/45) and Holczer et al. (2015, J/ApJ/807/170; 2016,
J/ApJS/225/9), we investigated TTVs for nearly all KOIs in Kepler's Data
Release 24 catalog. Using TTV plots, periodograms, and phase-folded
quadratic plus sinusoid fits, we visually rated each KOI's TTV data in
five categories. Our ratings emphasize the hundreds of planets with TTVs
that are weaker than the ∼200 that have been studied in detail. Our
findings are consistent with statistical methods for identifying strong
TTVs, though we found some additional systems worth investigation. Between
about 3-50 days and 1.3-6 Earth radii, the frequency of strong TTVs
increases with period and radius. As expected, strong TTVs are very common
when period ratios are near a resonance, but there is not a one-to-one
correspondence. The observed planet-by-planet frequency of strong TTVs
is only somewhat lower in systems with one or two known planets (7%±1%)
than in systems with three or more known planets (11%±2%). We attribute
TTVs to known planets in multitransiting systems but find ∼30 cases where
the perturbing planet is unknown. Our conclusions are valuable as an
ensemble for learning about planetary system architectures and individually
as stepping stones toward more-detailed mass-radius constraints. We also
discuss Data Release 25 TTVs, investigate ∼100 KOIs with transit duration
and/or depth variations, and estimate that the Transiting Exoplanet Survey
Satellite will likely find only ∼10 planets with strong TTVs.
Description:
We combined transit timing data from two sources: Holczer et al. (2016,
J/ApJS/225/9; H+16) and Rowe et al. (2014, J/ApJ/784/45) as updated by
Rowe & Thompson (2015arXiv150400707R 2015arXiv150400707R). Both sets of transit times are
based on all 17 quarters of Kepler Presearch Data Conditioning Maximum
A Posteriori (PDC-MAP) Long Cadence data retrieved from Milkuski Archive
for Space Telescopes (MAST) in 2013-2014. H+16 (an update of Mazeh et al.
2013, J/ApJS/208/16) focused on TTVs for 2599 planet candidate KOIs that
passed some basic tests described therein, but provided TTVs for 3164 KOIs.
As a product of the Kepler mission, the data from Rowe & Thompson
(2015arXiv150400707R 2015arXiv150400707R) were produced more automatically, homogeneously, and
for 4914 KOIs (including large numbers of known false positives). Most
of these overlap, and we inspected a total of 5930 KOIs.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table2.dat 565 5930 Combined exoplanet data table
table4.dat 44 44 Analyzed eclipsing binaries
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See also:
V/133 : Kepler Input Catalog (Kepler Mission Team, 2009)
J/ApJS/197/2 : Transit timing observations from Kepler. I. (Ford+, 2011)
J/ApJ/750/113 : Kepler TTVs. II. Confirmed multiplanet systems
(Ford+, 2012)
J/ApJS/208/16 : Kepler transit timing observations. VIII. (Mazeh+, 2013)
J/ApJ/784/45 : Kepler's multiple planet candidates. III. (Rowe+, 2014)
J/ApJ/787/80 : 139 Kepler planets transit time variations (Hadden+, 2014)
J/ApJ/807/170 : Prograde vs retrogade motions. II. KOIs (Holczer+, 2015)
J/ApJ/809/77 : Transiting Exoplanet Survey Satellite (TESS)
(Sullivan+, 2015)
J/AJ/152/158 : Final Kepler transiting planet search (DR25)
(Twicken+, 2016)
J/ApJS/225/9 : Kepler TTVs. IX. The full long-cadence data set
(Holczer+, 2016)
J/AJ/154/5 : Transit timing variations of 145 Kepler planets
(Hadden+, 2017)
J/A+A/615/A79 : KOINet. Study of exoplanet systems via TTVs
(von Essen+, 2018)
J/ApJS/234/9 : A spectral approach to transit timing variations
(Ofir+, 2018)
J/ApJS/235/38 : Kepler planetary cand. VIII. DR25 reliability
(Thompson+, 2018)
J/other/RAA/19.41 : TTVs + linear ephemerides of Kepler exoplanets
(Gajdos+, 2019)
Byte-by-byte Description of file: table2.dat
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Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 7 F7.2 --- KOI [1.01/5978.01] Kepler Object of Interest (KOI)
number
9- 18 E10.4 d PerSP [0.032613/109390] SinePoly best-fit period (1)
20- 29 E10.4 rad PhsSP [0.0004937/6.2828] SinePoly best-fit phase (1)
31- 40 E10.4 min AmpSP [2.4212e-05/6810500] SinePoly best-fit amplitude
(1)
42- 52 E11.4 min/d LinSP [-11007/2829.3] SinePoly best-fit linear
coefficient (1)
54- 64 E11.4 min/d2 QuadSP [-1.6195/5.242] SinePoly best-fit quadratic
coefficient (1)
66- 75 E10.4 --- Chi2SP [5.5467e-31/3.4689e+13] SinePoly best-fit
chi-square (1)
77- 84 I8 --- KIC [757450/12935144] Kepler Input Catalog number
(aka KID)
86- 97 A12 --- Planet Kepler planet name (2)
99-111 A13 --- EADisp Exoplanet Archive Disposition (2)
113 I1 --- ClRat [0/9] Cleanliness visual rating (9=fewest
outliers)
115 I1 --- SPFRat [0/9] SinePoly fit visual rating (9=outstanding
fit)
117 I1 --- PPRat [0/9] Periodogram peak visual rating (9=very
strong periodicity)
119 I1 --- SPPRat [0/9] SinePoly peak visual rating (9=very strong
periodicity)
121 I1 --- OvRat [0/9] Overall interest visual rating (9=very
strong TTV signal)
123 I1 --- Multi [0/7] Number of candidate/confirmed planets
in system
125-138 E14.8 d PerKOI [0.241842544/129995.778] KOI orbital period (2)
140-150 E11.5 d E_PerKOI [0/0.1568] Upper uncertainty in PerKOI (2)
152-162 E11.5 d e_PerKOI [0/0.1568] Lower uncertainty in PerKOI (2)
164-177 E14.8 d T0KOI [120.565925/746.196647] KOI transit epoch (BKJD)
(2)
179-189 E11.5 d E_T0KOI [0/0.579] Upper uncertainty in T0KOI (2)
191-201 E11.5 d e_T0KOI [0/0.579] Lower uncertainty in T0KOI (2)
203-210 E8.2 h DurKOI [0.34/93.2] KOI transit duration (2)
212-219 E8.2 h E_DurKOI [0/9.3] Upper uncertainty in DurKOI (2)
221-228 E8.2 h e_DurKOI [0/9.3] Lower uncertainty in DurKOI (2)
230-237 E8.2 --- KOIror [0/100] KOI planet/star radius ratio (2)
239-246 E8.2 --- E_KOIror [0/63.7] Upper uncertainty in KOIror (2)
248-255 E8.2 --- e_KOIror [0/69.9] Lower uncertainty in KOIror (2)
257-264 E8.2 Rgeo Rad [0/109000] KOI planet radius (2)
266-273 E8.2 Rgeo E_Rad [0/23400] Upper uncertainty in Rad (2)
275-282 E8.2 Rgeo e_Rad [0/32600] Lower uncertainty in Rad (2)
284-291 E8.2 --- SESKOI [0/18500] KOI maximum Single Event Statistic;
similar to signal-to-noise ratio of a single
transit (2)
293-300 E8.2 --- MESKOI [0/168000] KOI maximum Multiple Event Statistic;
similar to signal-to-noise ratio of all
transits combined (2)
302-306 I5 K Teff [2661/11068]? Stellar effective temperature (2)
308-311 I4 K E_Teff [0/1067]? Upper uncertainty in Teff (2)
313-315 I3 K e_Teff [0/798]? Lower uncertainty in Teff (2)
317-324 E8.2 Msun M* [0/3.55] Stellar mass (2)
326-333 E8.2 Msun E_M* [0/1.38] Upper uncertainty in M* (2)
335-342 E8.2 Msun e_M* [0/2.38] Lower uncertainty in M* (2)
344-347 F4.1 mag Kpmag [7/19.3] Target magnitude in Kepler bandpass (2)
349-357 E9.3 Mjup Mp [0.0002/100000] Planet mass (3)
359-367 E9.3 Mjup E_Mp [0.00019/100000] Upper uncertainty in Mp (3)
369-377 E9.3 Mjup e_Mp [0.00012/100000] Lower uncertainty in Mp (3)
379-387 E9.3 min TTVErr [0.06/100000] Median uncertainty on TTV
measurements (4)
389-397 E9.3 min TTVSct [0.08/100000] Robust scatter of TTV measurements
(4)
399-408 E10.3 [-] p-Rat [-16/100000] log10(p-value) for TTVSct/TTVErr
ratio (4)
410-418 E9.3 d PerH16 [1.55/100000] Period of highest TTV periodogram
peak (4)
420-429 E10.3 d2 PowH16 [-9.54/100000] Power of highest TTV periodogram
peak (4)
431-440 E10.3 [-] p-PS [-4/100000] log10(p-value) for highest TTV
periodogram peak (4)
442-451 E10.3 --- AlmH16 [-1.273/100000] Alarm score for TTV series (4)
453-462 E10.3 [-] p-Alm [-4/100000] log10(p-value) for TTV alarm score
(4)
464-472 E9.3 --- pdH16 [1/100000] Polynomial degree chosen for TTV fit
(4)
474-483 E10.3 [-] p-poly [-16/100000] log10(p-value) for TTV polynomial
fit (4)
485-495 E11.4 d LSPHR [-1/1968] Peak of Lomb-Scargle periodogram for
independent TTVs (5)
497-507 E11.4 d PerHR [-1/2415] Period from the independent TTV
sinusoidal curve-fit (5)
509-518 E10.4 d e_PerHR [1/1158] Uncertainty in PerHR (5)
520-530 E11.4 min AmpHR [-1/2900.2] Amplitude from independent TTV
sinusoidal curve-fit (5)
532-541 E10.4 min e_AmpHR [0.1/407] Uncertainty in AmpHR (5)
543-549 F7.2 --- KOIprt [-1/4913.02] KOI attributed to the cause of TTV
perturbations
551-552 I2 --- f_KOIprt [-1/6]? Flag determining perturbing KOI for
KOIprt (6)
554-555 I2 --- TDPV [-1/55] Flag describing transit duration/depth
variations (7)
557-560 I4 --- numH16 [0/2442] Number of transit times from
Holczer et al. (2016, J/ApJS/225/9)
562-565 I4 --- numRT [0/4734] Number of transit times from
Rowe & Thompson (2015arXiv150400707R 2015arXiv150400707R)
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Note (1): SinePoly is a quadratic+sinusoid fit to the Transit Timing Variation
data. It does not always reach the global minimum and not all of the
parameters are meaningful.
Note (2): Taken from the NASA Exoplanet Archive Cumulative KOI Table
(http://exoplanetarchive.ipac.caltech.edu/) downloaded on June 6, 2016. These
values were generally taken from the Kepler Data Release 24 pipeline. The
transiting object is called a "planet" since planet-based fits are used to
derive parameters listed here (e.g., radius), even though many KOIs are not
planets.
Note (3): Taken from the NASA Exoplanet Archive Confirmed Planets Table on
June 6, 2016.
Note (4): Taken from Holczer et al. 2016, J/ApJS/225/9 (H+16), see therein for
more information. Some p-values are truncated as in H+16.
Note (5): Taken from independent Transit Timing calculations and TTV fits. Plots
and discussion at http://exoplanetscience.org. Many KOIs do not have these
fits.
Note (6): Flag as follows (parentheses denote how many planets (not KOIs) have
the corresponding f_KOIprt):
-1 = Overall rating of 7 or below (3197);
0 = Overall rating of 8-9, but not in a multitransiting system (122);
1 = TTVs clearly caused by the planet listed in KOIprt (67);
2 = TTVs probably caused by the planet listed in KOIprt (11);
3 = TTVs could be caused by the planet listed in KOIprt (16);
4 = TTV signal inconsistent with neighboring planets (8);
5 = No planet within period ratio of 2.5 (27);
6 = Does not fit into any of the above categories (2).
Note (7): The inspection placed every potentially interesting signal into one of
three categories: noise/spurious, a slope worth further investigation, and an
oscillation worth further investigation. In particular, one or more of the
following values were assigned for all 97 KOIs:
1 = TDV noise/spurious;
2 = TDV slope worth further investigation;
4 = TDV oscillation worth further investigation;
10 = TPV noise/spurious;
20 = TPV slope worth further investigation;
40 = TPV oscillation worth further investigation;
-1 = KOI with no TDV/TPV measurements in Holczer et al. (2016, J/ApJS/225/9).
These values were summed to provide the final TDPV value.
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Byte-by-byte Description of file: table4.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 7 F7.2 --- KOI [225.01/5976.01] KOI number
9- 16 I8 --- KIC [1725193/12645761] KIC number
18- 22 F5.1 d Per [0.6/214.7] Period
24- 28 F5.2 mag Kpmag [10.15/16.35] Magnitude in Kepler bandpass
30- 34 I5 K Teff [4185/8750]? Effective temperature
36 I1 --- ClRat [4/9] Cleanliness visual rating (9=fewest outliers)
38 I1 --- SPFRat [5/9] SinePoly fit visual rating (9=outstanding
fit)
40 I1 --- PPRat [5/9] Periodogram peak visual rating (9=very strong
periodicity)
42 I1 --- SPPRat [0/9] SinePoly peak visual rating (9=very strong
periodicity)
44 I1 --- OvRat [5/9] Overall interest visual rating (9=very strong
TTV signal)
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History:
From electronic version of the journal
(End) Prepared by [AAS], Tiphaine Pouvreau [CDS] 18-Jul-2019