J/A+A/566/A103 Kepler planet host candidates imaging (Lillo-Box+, 2014)
High-resolution imaging of Kepler planet host candidates.
A comprehensive comparison of different techniques.
Lillo-Box J., Barrado D., Bouy H.
<Astron. Astrophys., 566, A103-103 (2014)>
=2014A&A...566A.103L 2014A&A...566A.103L
ADC_Keywords: Stars, double and multiple ; Planets
Keywords: techniques: high angular resolution -
planets and satellites: fundamental parameters - binaries: visual
Abstract:
The Kepler mission has discovered thousands of planet candidates.
Currently, some of them have already been discarded; more than 200
have been confirmed by follow-up observations (most by radial velocity
and few by other methods), and several hundreds have been validated.
However, the large majority of the candidates are still awaiting for
confirmation. Thus, priorities (in terms of the probability of the
candidate being a real planet) must be established for subsequent
radial velocity observations.
The motivation of this work is to provide a set of isolated (good)
host candidates to be further tested by other techniques that allow
confirmation of the planet. As a complementary goal, we aim to
identify close companions of the candidates that could have
contaminated the light curve of the planet host due to the large pixel
size of the Kepler CCD and its typical PSF of around 6 arcsec. Both
goals can also provide robust statistics about the multiplicity of the
Kepler hosts.
We used the AstraLux North instrument located at the 2.2m telescope in
the Calar Alto Observatory (Almeria, Spain) to obtain
diffraction-limited images of 174 Kepler objects of interest. A sample
of demoted Kepler objects of interest (with rejected planet
candidates) is used as a control for comparison of multiplicity
statistics. The lucky-imaging technique used in this work is compared
to other adaptive optics and speckle imaging observations of Kepler
planet host candidates. To that end, we define a new parameter, the
blended source confidence level (BSC), to assess the probability of an
object to have blended non-detected eclipsing binaries capable of
producing the detected transit.
Description:
We applied the lucky imaging technique to the selected targets to
achieve diffraction-limited resolution. We used the AstraLux North
instrument located at the 2.2m telescope at the Calar Alto Observatory
(Almeria, Spain). The targets were observed along three visibility
windows of the Kepler field during 2011, 2012, and 2013. The results
regarding the non-isolated KOIs of observations on 2011 were published
in Lillo-Box et al. (2012A&A...546A..10L 2012A&A...546A..10L, Cat. J/A+A/546/A10). In the
present work, we report the results concerning the isolated candidates
observed in 2011 and the new results for the 2012-2013 observing
runs.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 97 207 *Observational information, completeness, and
detectability magnitudes
table3.dat 116 100 Photometry of the 23 active and 18 demoted KOIs
with detected companions that are closer than
6arcsec in the new sample observed during
2012 and 2013
table4.dat 45 266 Sensitivity limit results (at 5σ level) for
all observed tagets in the 2011, 2012 and 2013
observing seasons.
table7.dat 56 280 Results of the blended source probability prior
and after the AstraLux images for 222 planet
candidates around isolated KOIs from all 3
observing runs (Type=0) and KOIs with detected
companions at 3-6" from the 2012 and
2013 observing runs (Type=1)
table10.dat 27 33 *Comparison between the improvements in the BSC
parameter obtained by using the H11, A12 and
our high-resolution images for all planet
candidates involved (28 in H11 and 27 in A12)
table11.dat 24 167 Comparison between the blended source probabilities
(PBS) obtained by using the L13 (Law et al.
2014ApJ...791...35L 2014ApJ...791...35L) and our high-resolution
images for coincident planet candidates
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Note on table1.dat: for the isolated KOIs observed with the Calar Alto/AstraLux
instrument during the 2011 observational season (62 KOIs in total) and all
targets observed during 2012 and 2013 seasons (20 and 57 KOIs, respectively).
The targets with close companions from 2011 (another 41 KOIs) were already
published in Lillo-Box et al. (2012A&A...546A..10L 2012A&A...546A..10L, Cat. J/A+A/546/A10).
Note on table10.dat: In all cases, the BSC (Blended Source Confidence level)
has been improved with respect to the speckle images and the A12 study.
Note that the common target KOI-0623 to H11 is not presented here because
we detected a stellar companion closer than 3arcsec. The small improvement
of the H11 study is mostly due to the reduced field of view, which avoids
detection of 1.5-3.0arcsec companions, where the probability of having a
background source is maximum in the 0-3arcsec range.
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See also:
V/133 : Kepler Input Catalog (Kepler Mission Team, 2009)
J/ApJ/728/117 : Kepler planetary candidates. I. (Borucki+, 2011)
J/ApJ/736/19 : Kepler planetary candidates. II. (Borucki+, 2011)
J/ApJS/204/24 : Kepler planetary candidates. III. (Batalha+, 2013)
J/ApJS/210/19 : Kepler planetary candidates. IV. 22 months (Burke+, 2014)
J/A+A/555/A58 : New Kepler planetary candidates (Ofir+, 2013)
J/AJ/142/19 : Speckle observations of KOI (Howell+, 2011)
J/AJ/144/42 : Infrared photometry of 90 KOIs (Adams+, 2012)
J/A+A/546/A10 : Multiplicity in transiting planet-host stars (Lillo-Box+, 2012)
Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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1 A1 --- n_KOI [AD] Active or Demoted KOI (G1)
3- 6 I4 --- KOI [1/4512] KOI number
8- 14 A7 --- Iref [HAL, ] Identifier of papers where
high-resolution images are provided (G2)
16- 23 I8 --- KIC KIC number (Cat. V/133)
25- 26 I2 h RAh Right ascension (J2000) (1)
28- 29 I2 min RAm Right ascension (J2000) (1)
31- 35 F5.2 s RAs Right ascension (J2000) (1)
37 A1 --- DE- Declination sign (J2000) (1)
38- 39 I2 deg DEd Declination (J2000) (1)
41- 42 I2 arcmin DEm Declination (J2000) (1)
44- 48 F5.2 arcsec DEs Declination (J2000) (1)
50- 55 F6.3 mag kepmag [7.8/18.8] Kepler magnitude
57- 66 A10 "date" Date Observation date
68 A1 --- Flt [iz] Filter name
70- 75 F6.4 s t.ind [0.02/0.2] Individual exposure time
77- 81 I5 --- Nfr [7580/45000] Number of frames
83- 87 F5.1 s t.eff [34/332] Effective time
89- 92 F4.1 mag iComp [16.5/19]?=- Estimated completeness magnitude
scaled to those found for the 200s image of
the globular cluster M15
94- 97 F4.1 mag iDet [19.8/23]?=- Estimated detectability magnitude
scaled to those found for the 200s image of
the globular cluster M15
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Note (1): Position from Borucki et al. (2011ApJ...736...19B 2011ApJ...736...19B, Cat. J/ApJ/736/19).
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Byte-by-byte Description of file: table3.dat
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Bytes Format Units Label Explanations
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1 A1 --- n_KOI [AD] Active or Demoted KOI (G1)
3- 6 I4 --- KOI [1/4512] KOI number
8 A1 --- m_KOI [ABCDE] Component
10- 15 F6.4 arcsec Sep Angular separation from component A (0 for A)
17- 22 F6.4 arcsec e_Sep ? rms uncertainty on Sep
24- 29 F6.2 deg PA Position angle with component A (0 for A)
31- 34 F4.2 deg e_PA ? rms uncertainty on PA
37- 41 F5.2 mag imag ?=- SDSS i magnitude
43- 46 F4.2 mag e_imag ? rms uncertainty on imag
48- 52 F5.2 mag zmag ?=- SDSS z magnitude
54- 57 F4.2 mag e_zmag ?=- rms uncertainty on zmag
59- 64 F6.3 mag Di ?=- Difference in i magnitude Δi with
component A (0 for A)
66- 70 F5.3 mag e_Di ? rms uncertainty on Di
72- 77 F6.3 mag Dz ?=- Difference in z magnitude Δz with
component A (0 for A)
79- 83 F5.3 mag e_Dz ? rms uncertainty on Dz
85- 90 F6.3 mag i-z ?=- SDSS i-z colour index
92- 96 F5.3 mag e_i-z ? rms uncertainty on i-z
98- 99 A2 --- SpT MK spectral type
101-105 A5 --- SpR Error on SpType (Interval of spectral type)
107-110 I4 yr Season [2012/2013] Season
112-116 A5 --- Iref [HAL, ] Identifier of papers that have
detected the KOI and/or the companion (G2)
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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 A1 --- n_KOI [AD] Active or Demoted KOI (G1)
3- 6 I4 --- KOI [1/4512] KOI number
8- 12 A5 --- Iref [HAL, ] Identifier of papers that have
detected the KOI and/or the companion (G2)
14 A1 --- Flt [iz] SDSS-Filter name
15 A1 --- f_mag [*] KIC magnitude not converted to SDSS (2)
16- 20 F5.2 mag mag ?=- Magnitude in the SDSS filter system
22- 25 F4.2 mag Dm0.2 ?=- Sensitivity limit magnitude at 5σ
Δm(0.2arcsec)
27- 30 F4.2 mag Dm0.5 ?=- Sensitivity limit magnitude at 5σ
Δm(0.5arcsec)
32- 35 F4.2 mag Dm1.0 ?=- Sensitivity limit magnitude at 5σ
Δm(1.0arcsec)
37- 40 F4.2 mag Dm2.0 ?=- Sensitivity limit magnitude at 5σ
Δm(2.0arcsec)
42- 45 F4.2 mag Dm3.0 ?=- Sensitivity limit magnitude at 5σ
Δm(3.0arcsec)
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Note (2): magnitude could not be converted to the SDSS system due to the lack
of some needed magnitudes in equations 3 and 4 of Pinsonneault et al.
(2012ApJS..199...30P 2012ApJS..199...30P).
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Byte-by-byte Description of file: table7.dat
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Bytes Format Units Label Explanations
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1 A1 --- n_KOI [AD] Active or Demoted KOI (G1)
3- 9 F7.2 --- KOI [1/4512] KOI of Planet candidate
11 I1 --- Type [0/1] Isolated (0) or not (1) type (1)
13- 17 F5.2 mag kepmag Kepler magnitude
19- 24 F6.2 mag Dmmax Maximum contrast (with respect to the measured
flux)
26- 29 F4.1 % PBS0 Prior probability of having a blended source
31- 34 F4.1 % PBS14 This paper high-resolution images improvements
in the BSC parameter
36- 40 F5.1 % Imp ?=- Corresponding improvement to PBS0
obtained with our high-resolution observations
42- 48 F7.4 % PEB ?=- Probability of that source being an
appropriate eclipsing binary
50- 56 F7.4 % PBB ?=- Probability of having a blended eclipsing
binary
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Note (1): Type as follows (see Sect. 4.1 for more details):
0 = isolated KOIs (no companions within 6 arcsec from the host star)
1 = KOIs with at least one companion between 3-6 arcsec (see Table 3 for
photometric information about the detected companions).
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Byte-by-byte Description of file: table10.dat
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Bytes Format Units Label Explanations
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1- 6 F6.2 --- KOI [1/4512] KOI of Planet candidate
8- 12 F5.2 % PBS0 Prior probability of having a blended source
14- 17 F4.1 % PBS11 ?=- Howell et al. (2011AJ....142...19H 2011AJ....142...19H) images
improvements in the BSC parameter
19- 22 F4.1 % PBS12 ?=- Adams et al. (2012AJ....144...42A 2012AJ....144...42A) images
improvements in the BSC parameter
24- 27 F4.1 % PBS14 This paper high-resolution images improvements
in the BSC parameter
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Byte-by-byte Description of file: table11.dat
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Bytes Format Units Label Explanations
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1- 7 F7.2 --- KOI [1/4512] KOI of Planet candidate
9- 13 F5.2 % PBS0 Prior probability of having a blended source
15- 19 F5.2 % PBS13 ?=- Law et al. (2014ApJ...791...35L 2014ApJ...791...35L) images
improvements in the BSC parameter
21- 24 F4.1 % PBS14 This paper high-resolution images improvements
in the BSC parameter
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Global notes:
Note (G1): Active KOIs (currently keeping at least one of their planet
candidates) are shown in the upper part of the table and demoted
(rejected) KOIs are shown in the bottom part of the table.
Note (G2): Identifier of papers where high-resolution images as follows:
H = Howell et al. (2011AJ....142...19H 2011AJ....142...19H, Cat. J/AJ/142/19)
A = Adams et al. (2012AJ....144...42A 2012AJ....144...42A, Cat. J/AJ/144/42)
L = Law et al. (2014ApJ...791...35L 2014ApJ...791...35L)
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History:
From electronic version of the journal
(End) Patricia Vannier [CDS] 09-Sep-2014