J/AJ/157/143 Kepler GK dwarf planet candidate samples (Burke+, 2019)
Re-evaluating small long-period confirmed planets from Kepler.
Burke C.J., Mullally F., Thompson S.E., Coughlin J.L., Rowe J.F.
<Astron. J., 157, 143 (2019)>
=2019AJ....157..143B 2019AJ....157..143B (SIMBAD/NED BibCode)
ADC_Keywords: Stars, dwarfs ; Stars, G-type ; Stars, K-type ; Exoplanets
Keywords: methods: statistical - planetary systems -
planets and satellites: detection -
planets and satellites: terrestrial planets - surveys -
techniques: photometric
Abstract:
We re-examine the statistical confirmation of small long-period Kepler
planet candidates in light of recent improvements in our understanding
of the occurrence of systematic false alarms in this regime. Using the
final Data Release 25 (DR25, Twicken et al. 2016, J/AJ/152/158) Kepler
planet candidate catalog statistics, we find that the previously confirmed
single-planet system Kepler-452b no longer achieves a 99% confidence
in the planetary hypothesis and is not considered statistically validated
in agreement with the finding of Mullally et al. (2018AJ....155..210M 2018AJ....155..210M).
For multiple planet systems, we find that the planet prior enhancement for
belonging to a multiple-planet system is suppressed relative to previous
Kepler catalogs, and we also find that the multiple-planet system member,
Kepler-186f, no longer achieves a 99% confidence level in the planetary
hypothesis. Because of the numerous confounding factors in the data
analysis process that leads to the detection and characterization of a
signal, it is difficult to determine whether any one planetary candidate
achieves a strict criterion for confirmation relative to systematic false
alarms. For instance, when taking into account a simplified model of
processing variations, the additional single-planet systems Kepler-443b,
Kepler-441b, Kepler-1633b, Kepler-1178b, and Kepler-1653b have a
non-negligible probability of falling below 99% confidence in the planetary
hypothesis. The systematic false alarm hypothesis must be taken into
account when employing statistical validation techniques in order to
confirm planet candidates that approach the detection threshold of a
survey. We encourage those performing transit searches of K2, TESS, and
other similar data sets to quantify their systematic false alarm rates.
Alternatively, independent photometric detection of the transit signal
or radial velocity measurements can eliminate the false alarm hypothesis.
Description:
In this study, we follow the procedure for statistical validation of
transiting planet signals using a Bayesian framework (Fressin et al.
2011ApJS..197....5F 2011ApJS..197....5F; Morton & Johnson 2011, J/ApJ/738/170; Torres et al.
2011ApJ...727...24T 2011ApJ...727...24T; Morton 2012ApJ...761....6M 2012ApJ...761....6M). In summary, the
validation calculation proceeds by specifying the likelihood that a
signal of interest matches what is expected of a bona fide planet (LPL),
an astrophysical false positive (LAFP), and a systematic false alarm
(LSFA), as well as a prior probability for each scenario (π(PL),
π(AFP), π(SFA)). In order to calculate π(PL) and π(SFA), we
use a subset of the Kepler targets that are optimized for studying planet
occurrence rates for GK dwarfs. See Burke et al. (2015, J/ApJ/809/8),
Christiansen (2017ksci.rept...18C), and Burke & Catanzarite
(2017ksci.rept...19B) for a full discussion, but in summary, in addition
to selecting targets based upon their spectral type, targets are selected
for their suitability as relatively quiet, well-behaved targets with
well-modeled recoverability of transit signals with the Kepler pipeline.
The target selection criteria were based upon studying a database of
1.2x108 transit injection and recovery trials over the Kepler targets
in order to reject targets with noise properties making them unsuitable
for an accurate quantification of their recovery for transit signals
(Burke & Catanzarite 2017ksci.rept...17B).
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 46 397 Kepler GK dwarf planet candidate samples
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See also:
V/133 : Kepler Input Catalog (Kepler Mission Team, 2009)
J/ApJ/738/170 : False positive Kepler planet candidates (Morton+, 2011)
J/ApJ/809/8 : Terrestrial planet occurrence rates for KOI stars
(Burke+, 2015)
J/AJ/152/158 : Final Kepler transiting planet search (DR25) (Twicken+, 2016)
J/ApJS/229/30 : Revised stellar properties of Q1-17 Kepler targets
(Mathur+, 2017)
J/ApJS/235/38 : Kepler planetary cand. VIII. DR25 reliability (Thompson+, 2018)
Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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1- 3 A3 --- Data Data identifier (1)
5- 11 F7.2 --- KOI [70.05/8275.01]? Kepler Object of Interest
identifier
13- 21 I9 --- KIC [1849702/12885212] Kepler Input Catalog identifier
23 I1 --- PNum [1/6] Planet number (2)
25- 31 F7.3 d Porb [12.163/636.52] Orbital period
33- 36 F4.2 Rgeo Rad [0.61/4.14] Planet radius
38- 41 F4.1 --- MES [7.1/15] Multiple Event Statistic (3)
43- 44 I2 --- TNum [3/99] Number of transits detected
46 I1 --- Quiet [0/1] Quiet Kepler detection flag (4)
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Note (1): Data identifier as follows:
OBS = Planet candidate identified in the unmodified DR25 Kepler data release
(Twicken et al. 2016, J/AJ/152/158);
INV = Planet candidate identified in the inversion modified data;
SC1 = Planet candidate identified in the scrambling one data set;
SC2 = Planet candidate identified in the scrambling two data set;
SC3 = Planet candidate identified in the scrambling three data set.
Note (2): Planet number is assigned in the order that they are found in the
Kepler pipeline search and it is used to identify the Kepler data products for
the specific candidate. In general, planets are identified in the pipeline in
order of decreasing SNR, which can differ from increasing in Porb order.
Note (3): Multiple Event Statistic is the detection significance.
Note (4): Flag as follows:
1 = Quiet detector analysis.
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History:
From electronic version of the journal
(End) Prepared by [AAS], Tiphaine Pouvreau [CDS] 08-Jul-2019