A sensitivity analysis of the WFCAM Transit Survey for short-period giant planets around M dwarfs

Kovács, G.; Hodgkin, S. T.; Sipőcz, Brigitta; Pinfield, D. J.; Barrado, D.; Birkby, Jayne; Cappetta, M.; Cruz, P.; Koppenhoefer, J.; Martín, E. L.; Murgas, F.; Nefs, B.; Saglia, R.; Zendejas, J.

doi:10.1093/mnras/stt571

Cited by 14 publications

(30 citation statements)

References 69 publications

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“…This is a significantly lower result than found in previous surveys where small sample sizes counteracted higher detection efficiencies. Splitting up the results for M0-M2 and M2-M4 sub groups as done in Kovács et al (2013) and Zendejas Dominguez et al (2013), we derive upper limits of 0.49% and 1.1%, respectively. However, we possess several plausible M dwarf hot Jupiter candidates.…”

Section: Detection Efficiencymentioning

confidence: 89%

“…k = 0. In order to compare our results to Kovács et al (2013) and Zendejas Dominguez et al (2013), we also use a confidence interval of 95%. Solving…”

Section: Detection Efficiencymentioning

confidence: 99%

“…This significantly decreased the detection efficiency. The change in observing time Kovács et al (2013), showing the hot Jupiter fractions determined by different surveys. We added our new results, marked in dark blue (upper limit) and light blue dotted line (fraction in case of a successful detection).…”

Section: Comparison To the Expected Number Of Detectionsmentioning

confidence: 99%

“…We added our new results, marked in dark blue (upper limit) and light blue dotted line (fraction in case of a successful detection). Orange shows the limits derived from radial velocity surveys , red from the Kepler survey (extracted by Kovács et al 2013), red in dotted lines from our own simulations for Kepler and green from the WFCAM transit survey (Zendejas Dominguez et al 2013). was shown to have a non-linear impact, e.g. doubling the amount of observing time increased the number of detected planets by a factor of three (see Tables 8 and 9 in Koppenhoefer et al 2009) for periods longer than 3 days.…”

Section: Comparison To the Expected Number Of Detectionsmentioning

confidence: 99%

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Pan-Planets: Searching for hot Jupiters around cool dwarfs

Obermeier

Koppenhoefer

Saglia

et al. 2016

A&A

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The Pan-Planets survey observed an area of 42 sq deg. in the galactic disk for about 165 h. The main scientific goal of the project is the detection of transiting planets around M dwarfs. We establish an efficient procedure for determining the stellar parameters T eff and log g of all sources using a method based on SED fitting, utilizing a three-dimensional dust map and proper motion information. In this way we identify more than 60 000 M dwarfs, which is by far the largest sample of low-mass stars observed in a transit survey to date. We present several planet candidates around M dwarfs and hotter stars that are currently being followed up. Using Monte Carlo simulations we calculate the detection efficiency of the Pan-Planets survey for different stellar and planetary populations. We expect to find 3.0 +3.3 −1.6 hot Jupiters around F, G, and K dwarfs with periods lower than 10 days based on the planet occurrence rates derived in previous surveys. For M dwarfs, the percentage of stars with a hot Jupiter is under debate. Theoretical models expect a lower occurrence rate than for larger main sequence stars. However, radial velocity surveys find upper limits of about 1% due to their small sample, while the Kepler survey finds a occurrence rate that we estimate to be at least 0.17( +0.67 −0.04 )%, making it even higher than the determined fraction from OGLE-III for F, G and K stellar types, 0.14( +0.15 −0.076 )%. With the large sample size of Pan-Planets, we are able to determine an occurrence rate of 0.11( +0.37 −0.02 )% in case one of our candidates turns out to be a real detection. If, however, none of our candidates turn out to be true planets, we are able to put an upper limit of 0.34% with a 95% confidence on the hot Jupiter occurrence rate of M dwarfs. This limit is a significant improvement over previous estimates where the lowest limit published so far is 1.1% found in the WFCAM Transit Survey. Therefore we cannot yet confirm the theoretical prediction of a lower occurrence rate for cool stars.

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Section: Detection Efficiencymentioning

confidence: 89%

“…k = 0. In order to compare our results to Kovács et al (2013) and Zendejas Dominguez et al (2013), we also use a confidence interval of 95%. Solving…”

Section: Detection Efficiencymentioning

confidence: 99%

Section: Comparison To the Expected Number Of Detectionsmentioning

confidence: 99%

Section: Comparison To the Expected Number Of Detectionsmentioning

confidence: 99%

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Pan-Planets: Searching for hot Jupiters around cool dwarfs

Obermeier

Koppenhoefer

Saglia

et al. 2016

A&A

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“…All observations for the WTS are done in the J-band (λ eff ≈ 1200 nm). For more details about the WTS, we refer to Kovács et al (2013). The image reduction procedure is described in the next section.…”

Section: The Wide Field Camera Transit Surveymentioning

confidence: 99%

Searching for transits in the Wide Field Camera Transit Survey with difference-imaging light curves

Dominguez

Koppenhoefer

Saglia

et al. 2013

A&A

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The Wide Field Camera Transit Survey is a pioneer program aiming at for searching extra-solar planets in the near-infrared. The images from the survey are processed by a data reduction pipeline, which uses aperture photometry to construct the light curves. We produce an alternative set of light curves using the difference-imaging method for the most complete field in the survey and carry out a quantitative comparison between the photometric precision achieved with both methods. The results show that differencephotometry light curves present an important improvement for stars with J > 16. We report an implementation on the box-fitting transit detection algorithm, which performs a trapezoid-fit to the folded light curve, providing more accurate results than the boxfitting model. We describe and optimize a set of selection criteria to search for transit candidates, including the V-shape parameter calculated by our detection algorithm. The optimized selection criteria are applied to the aperture photometry and difference-imaging light curves, resulting in the automatic detection of the best 200 transit candidates from a sample of ∼475 000 sources. We carry out a detailed analysis in the 18 best detections and classify them as transiting planet and eclipsing binary candidates. We present one planet candidate orbiting a late G-type star. No planet candidate around M-stars has been found, confirming the null detection hypothesis and upper limits on the occurrence rate of short-period giant planets around M-dwarfs presented in a prior study. We extend the search for transiting planets to stars with J ≤ 18, which enables us to set a stricter upper limit of 1.1%. Furthermore, we present the detection of five faint extremely-short period eclipsing binaries and three M-dwarf/M-dwarf binary candidates. The detections demonstrate the benefits of using the difference-imaging light curves, especially when going to fainter magnitudes.

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