J/ApJ/770/69 Kepler planet candidates radii (Petigura+, 2013)
A plateau in the planet population below twice the size of Earth.
Petigura E.A., Marcy G.W., Howard A.W.
<Astrophys. J., 770, 69 (2013)>
=2013ApJ...770...69P 2013ApJ...770...69P
ADC_Keywords: Planets ; Stars, double and multiple ; Stars, diameters ;
Effective temperatures
Keywords: planetary systems; stars: statistics; techniques: photometric
Abstract:
We carry out an independent search of Kepler photometry for small
transiting planets with sizes 0.5-8.0 times that of Earth and orbital
periods between 5 and 50 days, with the goal of measuring the fraction
of stars harboring such planets. We use a new transit search
algorithm, TERRA, optimized to detect small planets around
photometrically quiet stars. We restrict our stellar sample to include
the 12000 stars having the lowest photometric noise in the Kepler
survey, thereby maximizing the detectability of Earth-size planets. We
report 129 planet candidates having radii less than 6RE found in
three years of Kepler photometry (quarters 1-12). Forty-seven of these
candidates are not in Batalha et al. (J/ApJS/204/24), which only
analyzed photometry from quarters 1-6. We gather Keck HIRES spectra
for the majority of these targets leading to precise stellar radii and
hence precise planet radii. We make a detailed measurement of the
completeness of our planet search. We inject synthetic dimmings from
mock transiting planets into the actual Kepler photometry. We then
analyze that injected photometry with our TERRA pipeline to assess our
detection completeness for planets of different sizes and orbital
periods. We compute the occurrence of planets as a function of planet
radius and period, correcting for the detection completeness as well
as the geometric probability of transit, R*/a. The resulting
distribution of planet sizes exhibits a power law rise in occurrence
from 5.7RE down to 2RE, as found in Howard et al.
(2012ApJS..201...15H 2012ApJS..201...15H). That rise clearly ends at 2RE. The occurrence
of planets is consistent with constant from 2RE toward 1RE. This
unexpected plateau in planet occurrence at 2RE suggests distinct
planet formation processes for planets above and below 2RE.
Description:
We obtained spectra for 100 of the 129 stars with planet candidates
detected with the TERRA pipeline using HIRES at the Keck I telescope
with the standard configuration of the California Planet Survey (Marcy
et al. 2008PhST..130a4001M 2008PhST..130a4001M). These spectra have resolution of ∼50000,
at an S/N of 45/pixel at 5500Å.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table2.dat 89 129 Planet candidates identified with TERRA
table3.dat 38 162 Union of Batalha et al. 2013 (J/ApJS/204/24)
and TERRA Planet Candidate Catalogs
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See also:
V/133 : Kepler Input Catalog (Kepler Mission Team, 2009)
J/ApJS/207/35 : Kepler pipeline signal-to-noise studies (Christiansen+, 2013)
J/ApJS/204/24 : Kepler planetary candidates. III. (Batalha+, 2013)
J/ApJ/763/41 : Kepler multiple-candidate systems radii (Ciardi+, 2013)
J/ApJ/738/170 : False positive Kepler planet candidates (Morton+, 2011)
J/ApJ/736/19 : Kepler planetary candidates. II. (Borucki+, 2011)
J/ApJ/728/117 : Kepler planetary candidates. I. (Borucki+, 2011)
J/AJ/142/112 : KIC photometric calibration (Brown+, 2011)
J/ApJS/197/8 : Kepler's candidate mult. transiting planets (Lissauer+, 2011)
J/other/Sci/330.653 : Detected planets in the Eta-Earth Survey (Howard+, 2010)
Byte-by-byte Description of file: table2.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 8 I8 --- KIC [2142522/12737015] Kepler identifier (V/133)
10- 15 F6.3 d Per [5/49.6] Orbital period (1)
17- 23 F7.3 d T0 Time of transit center (BJD-2454900) (1)
25- 28 F4.2 % Rp/R* [0.5/5.7] Planet-to-star radius ratio (1)
30- 33 F4.2 % e_Rp/R* [0.05/0.7] Rp/R* uncertainty
35- 38 F4.2 h tau [0.4/8.1] Time for the planet to travel R*
during transit (τ) (1)
40- 43 F4.2 h e_tau [0.02/4] tau uncertainty
45 A1 --- l_b Limit flag on b
47- 50 F4.2 --- b [0.2/1] Transit impact parameter b (1)
52- 55 F4.2 --- e_b [0.01/0.3]? b uncertainty
57- 60 I4 K Teff [4692/6179] Effective temperature (2)
62- 65 F4.2 [cm/s2] logg [3.8/4.7] Surface gravity (2)
67- 70 F4.2 Rsun R* [0.6/2.5] Stellar radius (2)
72- 75 F4.2 Rgeo Rp [0.5/5.6] Planet radius
77- 80 F4.2 Rgeo e_Rp [0.06/1.1] Rp uncertainty
82- 83 A2 --- Src Source of stellar parameters (3)
85 A1 --- FP [YN] False positive?
87 A1 --- B12 Candidate present in Batalha et al. 2013
(J/ApJS/204/24)?
89 A1 --- n_KIC [n] new candidate identified with TERRA
(column added by CDS) (4)
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Note (1): Parameters determined from the Mandel & Agol (2002ApJ...580L.171M 2002ApJ...580L.171M)
light curve fit.
Note (2): By default, stellar parameters R*, Teff, and logg come from the
SpecMatch routine (A. W. Howard et al. 2013, in preparation).
If SpecMatch parameters do not exist, parameters are taken from the
corrected KIC values, described in Section 4.
Note (3): Source as follows:
S = SpecMatch-derived parameters using Keck HIRES spectra,
P1 = photometrically-derived parameters from Batalha et al. (2013,
J/ApJS/204/24),
P2 = photometrically-derived parameters computed by the authors.
See Section 4 for more details.
Note (4): The 37 TERRA candidates not in Batalha et al. (J/ApJS/204/24) and
not listed as false positives by the Kepler team (table 4).
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Byte-by-byte Description of file: table3.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 8 I8 --- KIC [2142522/12737015] Kepler identifier
10- 16 F7.2 --- KOI [5.02/2582.01]? KOI planet identifier (1)
18- 22 F5.2 d PerB [5.2/49.2]? Period from Batalha et al. (1)
24- 27 F4.2 Rgeo RpB [0.5/6.3]? Planet radius from Batalha et al.(1)
29- 33 F5.2 d Per [5/49.6]? TERRA period
35- 38 F4.2 Rgeo Rp [0.5/5.6]? TERRA planet radius
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Note (1): From Batalha et al. 2013 (J/ApJS/204/24)
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History:
From electronic version of the journal
(End) Emmanuelle Perret [CDS] 08-Jan-2015