J/MNRAS/379/647 SuperWASP-North extrasolar planet candidates (Lister+, 2007)
SuperWASP-North extrasolar planet candidates: candidates from fields 17h<RA<18h.
Lister T.A., West R.G., Wilson D.M., Cameron A.C., Clarkson W.I.,
Street R.A., Enoch B., Parley N.R., Christian D.J., Kane S.R., Evans A.,
Fitzsimmons A., Haswell C.A., Hellier C., Hodgkin S.T., Horne K., Irwin J.,
Keenan F.P., Norton A.J., Osborne J., Pollacco D.L., Ryans R., Skillen I.,
Wheatley P.J., Barnes J.R.
<Mon. Not. R. Astron. Soc., 379, 647-662 (2007)>
=2007MNRAS.379..647L 2007MNRAS.379..647L
ADC_Keywords: Planets ; Photometry ; Stars, diameters
Keywords: methods: data analysis - techniques: photometric - surveys -
planetary systems
Abstract:
We have performed photometric observations of nearly seven million
stars with 8<V<15 with the SuperWASP-North instrument from La
Palma between 2004 May to September. Fields in the right ascension
range 17-18h, yielding over 185000 stars with sufficient quality
data, have been searched for transits using a modified box
least-squares (BLS) algorithm. We find a total of 58 initial
transiting candidates which have high signal-to-noise ratio in the
BLS, show multiple transit-like dips and have passed visual
inspection. Analysis of the blending and the inferred planetary radii
for these candidates leave, a total of seven transiting planet
candidates which pass all the tests plus four which pass the majority.
We discuss the derived parameters for these candidates and their
properties and comment on the implications for future transit
searches.
Description:
The photometric data were obtained with the SuperWASP-North (SW-N)
instrument at the Observatorio del Roque de los Muchachos, La Palma,
Canary Islands, during 2004 May to September. Follow-up spectroscopic
observations of a small number of transit candidates were obtained by
one of us (JRB) as part of another observing program using the 3.6-m
CanadaFranceHawaii Telescope (CFHT) and ESPaDOnS echelle spectrograph
on Mauna Kea, Hawaii, on the nights of 2005 September 23-24.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table3.dat 114 61 Low-amplitude candidate extrasolar planets
table4.dat 92 63 Radius and blending results
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See also:
J/MNRAS/372/1117 : SuperWASP exoplanetary transit survey (Christian+, 2006)
J/A+A/467/785 : SuperWASP/ROSAT periodic variable stars (Norton+, 2007)
J/MNRAS/379/816 : SuperWASP-North extrasolar planet candidates (Street+, 2007)
Byte-by-byte Description of file: table3.dat
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Bytes Format Units Label Explanations
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1- 5 A5 --- --- [Field]
7- 17 A11 --- Field Field designation (SWHHMM+DDMM)
19- 37 A19 --- 1SWASP 1SWASP designation (JHHMMSS.ss+DDMMSS.s)
38 A1 --- n_1SWASP [c] Selection note (G1)
40- 47 F8.6 d Per Period
49- 54 F6.4 mag Delta Transit depth
56- 60 F5.3 h Dur Transit duration
62- 73 F12.4 d Epoch Epoch, in JD
75- 76 I2 --- Ntr Number of transits
78- 87 F10.4 --- Delta.chi2 Transit depth (Delta) multiplied by
goodness of fit statistic (chi2)
89- 95 F7.4 --- Rchi2 Ratio of Δχ2 with a transit
model to the /Δχ2 of an
antritransit model
97-102 F6.3 --- S/Nell Signal-to-noise ratio of the ellipsoidal
variation (2)
104-109 F6.3 --- Sred Signal-to-noise red ratio (3)
111-114 I4 --- LCcode LC four-digit code (4)
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Note (2): S/N of the ellipsoidal variation (S/Nell)<8
(based on a cosine fit to the out-of-transit data .
Note (3): Ratio of the best-fitting transit depth to the rms scatter when
binned on the expected transit duration and gives a measure of
the reliability of a transit detection.
Note (4): Four-digit coding scheme is:
* First digit: shape and visibility of the transit:
1 = clear transit-shaped signal of credible width and depth
2 = shallow/noisy but clearly visible transit signal
3 = transit barely visible, either very shallow, lost in noise
or ill-shaped
4 = partial transit or gaps around phase 0 but still showing clear
transit morphology
5 = signs of a dip at phase 0 but no clear in/egress
* Second digit: out-of-transit light curve:
1 = clean and flat, no other variations
2 = noisy but flat
3 = signs of ellipsoidal variation or suspected secondary eclipses
(includes some candidates which have been folded on twice the period)
4 = shows low-amplitude sinusoidal variation on short time-scales,
giving a knotty appearance (can indicate that the light curve
is folded on the wrong period)
5 = realistic variability of some other form out of transit
6 = multi-level or jumpy light curves (can indicate the wrong
period or photometry artefacts)
* Third digit: distribution of points in the folded light curve:
1 = smoothly sampled with a similar density of points throughout
2 = some minor regions with slightly lower density of points,
retaining a clear signal
3 = significant clumpiness of data points (can indicate a
pathological period)
* Fourth digit: credibility of determined period
1 = no reason to doubt measured period, clear peak in D.chi2 periodogram
2 = period gives a secure signal visible in the folded light
curve, but peak lies close to a known alias. Sometimes
associated with gaps in the folded light curve
3 = signal visible in folded light curve but period is a known
alias or peak lies at a commonly occurring frequency
4 = light curve suggests that the measured period is wrong
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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- 5 A5 --- --- [Field]
7- 17 A11 --- Field Field designation (SWHHMM+DDMM)
19- 37 A19 --- 1SWASP 1SWASP designation (JHHMMSS.ss+DDMMSS.s)
38 A1 --- n_1SWASP [c] Selection note (G1)
40- 45 F6.3 mag Vmag SW V magnitude
47- 50 F4.2 mag V-K ?=- V(SW)-K colour index
52- 55 F4.2 mag J-H J-H colour index
57- 61 F5.2 mag H-K H-K colour index
63- 66 F4.2 solRad Rs Star radius
67 A1 --- n_Rs [d] d: Based on J-H colour not a V-K colour
69- 72 F4.2 --- Rp Planet radius, in units of Jupier radius
73 A1 --- n_Rp [d] d: Based on J-H colour not a V-K colour
75- 78 F4.2 --- etap Exoplanet diagnostic (1)
79 A1 --- n_etap [d] d: Based on J-H colour not a V-K colour
81 I1 --- Nbr Number of brighter objects within aperture
83- 84 I2 --- Nft Number of objects less than 5mag fainter
within aperture
86 A1 --- rad Radius code (2)
88 A1 --- eta Eta code (3)
90- 92 A3 --- bl Blending code (4)
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Note (1): Exoplanet diagnostic defined as etap=Dobs/D where Dobs is the
observed transit duration and D is the theoretical transit duration.
Note (2): Radius code as follows:
A = Rp<1.6
B = 1.6≥Rp>1.75
C = Rp≥1.75
Note (3): Eta code as follows:
A = 0.5≥etap≥1.5
B = etap<0.5
C = etap>1.5
Note (4): Blending code as follows:
A = OK
B = 1 or 2 fainter objects in aperture
C = >2 fainter objects in aperture
D = brighter objects in aperture
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Global notes:
Note (G1): 'c' indicates a star not selected as a candidate,
but which has spectroscopic data.
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History:
From electronic version of the journal
References:
Christian et al., 23h<RA<03h 2006MNRAS.372.1117C 2006MNRAS.372.1117C, Cat. J/MNRAS/372/1117
Street et al., 18h<RA<21h 2007MNRAS.379..816S 2007MNRAS.379..816S, Cat. J/MNRAS/379/816
Clarkson et al., 03h<RA<06h 2007MNRAS.381..851C 2007MNRAS.381..851C
(End) Patricia Vannier [CDS] 26-Nov-2007