J/AJ/158/109 Occurrence rates of planets orbiting FGK stars (Hsu+, 2019)
Occurrence rates of planets orbiting FGK stars: combining Kepler DR25, Gaia DR2,
and Bayesian inference.
Hsu D.C., Ford E.B., Ragozzine D., Ashby K.
<Astron. J., 158, 109-109 (2019)>
=2019AJ....158..109H 2019AJ....158..109H (SIMBAD/NED BibCode)
ADC_Keywords: Exoplanets ; Stars, F-type ; Stars, G-type ; Stars, K-type ;
Models
Keywords: catalogs - methods: data analysis - methods: statistical -
planetary systems - stars: statistics
Abstract:
We characterize the occurrence rate of planets, ranging in size from
0.5 to 16 R⊕, orbiting FGK stars with orbital periods from 0.5
to 500 days. Our analysis is based on results from the "DR25" catalog
of planet candidates produced by NASA's Kepler mission and stellar radii
from Gaia "DR2" (Cat. I/345). We incorporate additional Kepler data
products to accurately characterize the efficiency of planets being
recognized as "threshold crossing events" by Kepler's Transiting Planet
Search pipeline and labeled as planet candidates by the robovetter.
Using a hierarchical Bayesian model, we derive planet occurrence rates
for a wide range of planet sizes and orbital periods. For planets with
sizes 0.75-1.5 R⊕ and orbital periods of 237-500 days, we find
a rate of planets per FGK star of <0.27 (84.13th percentile). While
the true rate of such planets could be lower by a factor of ∼2 (primarily
due to potential contamination of planet candidates by false alarms),
the upper limits on the occurrence rate of such planets are robust to
∼10%. We recommend that mission concepts aiming to characterize
potentially rocky planets in or near the habitable zone of Sun-like
stars prepare compelling science programs that would be robust for a true
rate in the range fR,P=0.03-0.40 for 0.75-1.5 R⊕ planets with
orbital periods in 237-500 days, or a differential rate of
Γ⊕=(d2f)/[d(lnP)d(lnRp)]=0.06-0.76.
Description:
We report occurrence rates inferred using a hierarchical Bayesian
model and Approximate Bayesian Computation (ABC), and incorporating
several improvements relative to previous studies, including the DR25
catalog of planet candidates, updates to the host star properties from
Gaia, and an improved model for the Kepler efficiency for detecting
and vetting of planet candidates.
In Table 4, we present our DR25 occurrence rates for F, G, and K stellar
types as defined by the Study Analysis Group (SAG) 13 of the NASA Exoplanet
Exploration Program Analysis Group (ExoPAG).
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table2.dat 81 130 Inferred planet occurrence rates
table4.dat 101 48 ExoPaG occurrence rates
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See also:
I/345 : Gaia DR2 (Gaia Collaboration, 2018)
J/ApJ/795/64 : A catalog of exoplanet physical parameters
(Foreman-Mackey+, 2014)
J/ApJ/814/130 : Planet occurrence rates calculated for KOIs (Mulders+, 2015)
J/AJ/152/158 : Final Kepler transiting planet search (DR25) (Twicken+, 2016)
J/AJ/155/205 : Occurrence rates for Q1-Q16 KOI catalog planet cand.
(Hsu+, 2018)
J/ApJS/235/38 : Kepler planetary cand. VIII. DR25 reliability (Thompson+, 2018)
Byte-by-byte Description of file: table2.dat
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Bytes Format Units Label Explanations
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1- 6 F6.2 d b_Per [0.5/256] Period range, lower value
8- 13 F6.2 d B_Per [1/500] Period range, upper value
15- 19 F5.2 Rgeo b_Rad [0.5/12] Planet radius range, lower value
21- 25 F5.2 Rgeo B_Rad [0.75/16] Planet radius range, upper value
27 A1 --- l_fVett [<] Limit flag on fVett
28- 35 E8.4 --- fVett [0.00015/0.93] Occurrence rate based on combined
detection and vetting efficiency model (1)
37- 43 E7.3 --- e_fVett [0.0001/0.096]? Lower limit uncertainty in fVett
45- 52 E8.4 --- E_fVett [0.00014/0.119]? Upper limit uncertainty in
fVett
54 A1 --- l_fNoVett [<] Limit flag on fNoVett
55- 63 E9.5 --- fNoVett [0.00016/0.95] Occurrence rate based on
no vetting efficiency model (1)
65- 72 E8.4 --- e_fNoVett [0.00013/0.075]? Lower limit uncertainty
in fNoVett
74- 81 E8.4 --- E_fNoVett [9.5e-05/0.089]? Upper limit uncertainty
in fNoVett
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Note (1): Estimated occurrence rates for DR25 KOI catalog planet candidates
associated with FGK stars using two different vetting efficiency schemes.
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Byte-by-byte Description of file: table4.dat
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Bytes Format Units Label Explanations
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1- 6 F6.2 d b_Per [10/320] Period range, lower value
8- 13 F6.2 d B_Per [20/640] Period range, upper value
15- 19 F5.2 Rgeo b_Rad [0.67/11.39] Planet radius range, lower value
21- 25 F5.2 Rgeo B_Rad [1/17.09] Planet radius range, upper value
27 A1 --- l_fTypeF [<] Limit flag on fTypeF
28- 35 E8.4 --- fTypeF [0.0037/1] Occurrence rate for F stellar type (1)
37- 43 E7.3 --- e_fTypeF [0.0063/0.37]? Lower limit uncertainty in fTypeF
45- 51 E7.3 --- E_fTypeF [0.0057/0.35]? Upper limit uncertainty in fTypeF
53 A1 --- l_fTypeG [<] Limit flag on TypeG
54- 60 E7.3 --- fTypeG [0.00146/0.97] Occurrence rate for G stellar type
(1)
62- 68 E7.3 --- e_fTypeG [0.00086/0.24]? Lower limit uncertainty in fTypeG
70- 76 E7.3 --- E_fTypeG [0.0012/0.26]? Upper limit uncertainty in fTypeG
78 A1 --- l_fTypeK [<] Limit flag on fTypeK
79- 85 E7.3 --- fTypeK [0.0021/1] Occurrence rate for K stellar type (1)
87- 93 E7.3 --- e_fTypeK [0.0022/0.2]? Lower limit uncertainty in fTypeK
95-101 E7.3 --- E_fTypeK [0.0023/0.28]? Upper limit uncertainty in fTypeK
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Note (1): ExoPAG grid estimated occurrence rates for DR25 KOI catalog planet
candidates associated with FGK stars, using the combined detection and vetting
efficiency.
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History:
From electronic version of the journal
(End) Tiphaine Pouvreau [CDS] 18-Oct-2019