J/ApJ/790/31 Transit times and durations of three KOIs (Nesvorny+, 2014)
Photo-dynamical analysis of three Kepler Objects of Interest with significant
transit timing variations.
Nesvorny D., Kipping D., Terrell D., Feroz F.
<Astrophys. J., 790, 31 (2014)>
=2014ApJ...790...31N 2014ApJ...790...31N (SIMBAD/NED BibCode)
ADC_Keywords: Stars, double and multiple ; Planets ; Ephemerides
Keywords: planets and satellites: detection -
planets and satellites: dynamical evolution and stability -
planets and satellites: individual: (KOI-227, KOI-319, KOI-884)
Abstract:
KOI-227, KOI-319 and KOI-884 are identified here as (at least) two
planet systems. For KOI-319 and KOI-884, the observed Transit Timing
Variations (TTVs) of the inner transiting planet are used to detect an
outer non-transiting planet. The outer planet in KOI-884 is ≃2.6
Jupiter masses and has the orbital period just narrow of the 3:1
resonance with the inner planet (orbital period ratio 2.93). The
distribution of parameters inferred from KOI-319.01's TTVs is bimodal
with either a ≃1.6 Neptune-mass (MN) planet wide of the 5:3
resonance (period 80.1 days) or a ≃1 Saturn-mass planet wide of the
7:3 resonance (period 109.2 days). The radial velocity measurements
can be used in this case to determine which of these parameter modes
is correct. KOI-227.01's TTVs with large ≃10 hr amplitude can be
obtained for planetary-mass companions in various major resonances.
Based on the Bayesian evidence, the current TTV data favor the outer
2:1 resonance with a companion mass ≃1.5 MN, but this solution
implies a very large density of KOI-227.01. The inner and outer 3:2
resonance solutions with sub-Neptune-mass companions are physically
more plausible, but will need to be verified.
Description:
Briefly, our analysis consists of two steps. In the first step, we fit
a transit model to the Kepler photometry. This gives us time,
duration, and other basic parameters of each transit, and their
relative uncertainties. In the second step, we attempt to model the
inferred transit times and durations as being caused by the
gravitational interaction with a planetary, stellar or lunar
companion. Note that we do not require that the companion itself to be
transiting, although cases with multiple transiting bodies can be
accommodated as well (e.g., Kipping et al. 2014ApJ...784...28K 2014ApJ...784...28K). This
two-step method is a useful alternative to a general photo-dynamical
method, where a N-body integration scheme is used to directly fit the
Kepler photometry (e.g., Carter et al. 2012Sci...337..556C 2012Sci...337..556C). The main
advantage of the general method is that it fits for a smaller number
of parameters and more directly links computed uncertainties to the
photometry. The main advantage of the two-step method is its
transparency, which makes it easier to understand of how different
dynamical parameters relate to the measured properties of transits.
Objects:
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RA (ICRS) DE Designation(s)
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18 57 24.49 +41 31 09.1 KOI-227 = KIC 6185476
19 20 28.20 +44 52 22.5 KOI-319 = KIC 8684730
19 14 34.21 +43 02 21.5 KOI-884 = KIC 7434875
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File Summary:
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FileName Lrecl Records Explanations
--------------------------------------------------------------------------------
ReadMe 80 . This file
table2.dat 92 134 Transit times and durations of KOI-227.01,
KOI-319.01 and KOI-884.02
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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/821/47 : KOI transit probabilities of multi-planet syst.
(Brakensiek+, 2016)
Byte-by-byte Description of file: table2.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
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1- 10 A10 --- ID Kepler identifier
(KOI-227.01, KOI-319.01, KOI-884.02)
12- 14 I3 --- Cycle Cycle
16- 33 F18.12 d tau Modified Julian Date of mid-transit
35- 50 F16.14 d e_tau Error in tau
52- 70 F19.17 d T Transit duration
72- 92 F21.19 d e_T Error in T
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History:
From electronic version of the journal
(End) Prepared by [AAS], Tiphaine Pouvreau [CDS] 17-Mar-2017