The Kepler photometer focal plane array

Argabright, Vic S.; VanCleve, Jeffrey E.; Bachtell, E. E.; Hegge, M. J.; McArthur, Scot; Dumont, F. C.; Rudeen, A.; Pullen, J. L; Teusch, Dennis A.; Tennant, D. S.; Atcheson, Paul

doi:10.1117/12.789913

Cited by 20 publications

(12 citation statements)

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“…Van Cleve & Caldwell (2009) and Argabright et al (2008) give an overview of the Kepler instrument, and Caldwell et al (2010) and Jenkins et al (2010b) provide a summary of its performance since launch. The Kepler observations of Kepler-19 that we present in this work were gathered from 2009 May 5 to 2011 March 5.…”

Section: Kepler Observationsmentioning

confidence: 99%

THE KEPLER-19 SYSTEM: A TRANSITING 2.2R_⊕PLANET AND A SECOND PLANET DETECTED VIA TRANSIT TIMING VARIATIONS

Ballard

Fabrycky

Fressin

et al. 2011

ApJ

146

109

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We present the discovery of the Kepler-19 planetary system, which we first identified from a 9.3 day periodic transit signal in the Kepler photometry. From high-resolution spectroscopy of the star, we find a stellar effective temperature T eff = 5541 ± 60 K, a metallicity [Fe/H] = −0.13 ± 0.06, and a surface gravity log(g) = 4.59 ± 0.10. We combine the estimate of T eff and [Fe/H] with an estimate of the stellar density derived from the photometric light curve to deduce a stellar mass of M = 0.936 ± 0.040 M and a stellar radius of R = 0.850 ± 0.018 R (these errors do not include uncertainties in the stellar models). We rule out the possibility that the transits result from an astrophysical false positive by first identifying the subset of stellar blends that reproduce the precise shape of the light curve. Using the additional constraints from the measured color of the system, the absence of a secondary source in the high-resolution spectrum, and the absence of a secondary source in the adaptive optics imaging, we conclude that the planetary scenario is more than three orders of magnitude more likely than a blend. The blend scenario is independently disfavored by the achromaticity of the transit: we measure a transit depth with Spitzer at 4.5 μm of 547 +113 −110 ppm, consistent with the depth measured in the Kepler optical bandpass of 567 ± 6 ppm (corrected for stellar limb darkening). We determine a physical radius of the planet Kepler-19b of R p = 2.209 ± 0.048 R ⊕ ; the uncertainty is dominated by uncertainty in the stellar parameters. From radial velocity observations of the star, we find an upper limit on the planet mass of 20.3 M ⊕ , corresponding to a maximum density of 10.4 g cm −3 . We report a significant sinusoidal deviation of the transit times from a predicted linear ephemeris, which we conclude is due to an additional perturbing body in the system. We cannot uniquely determine the orbital parameters of the perturber, as various dynamical mechanisms match the amplitude, period, and shape of the transit timing signal and satisfy the host star's radial velocity limits. However, the perturber in these mechanisms has a period 160 days and mass 6 M Jup , confirming its planetary nature as . We place limits on the presence of transits of in the available Kepler data.

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Section: Kepler Observationsmentioning

confidence: 99%

THE KEPLER-19 SYSTEM: A TRANSITING 2.2R_⊕PLANET AND A SECOND PLANET DETECTED VIA TRANSIT TIMING VARIATIONS

Ballard

Fabrycky

Fressin

et al. 2011

ApJ

146

109

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“…Cross talk from the FGS clocks to the science CCD video signals injects a complex pattern into the bias image of every science channel with an amplitude up to 20 DN read −1 . 3 Because the FGS and science CCDs share the same master clock, the pattern is spatially fixed; however, the amplitude of the cross talk is dependent on the temperature of the Local Detector Electronics (LDE). The cross talk has three distinct components based on the state of the FGS CCDs as the science pixel is read out (see Figure 2a): FGS CCD frame transfer, parallel transfer, and serial transfer.…”

Section: Description Of Artifactsmentioning

confidence: 99%

“…Previously, authors have described mission design and overall performance 2 , photometer design 3,4 , in-flight instrument performance 5,8 , and the overall data processing scheme 6 . Caldwell et al 4 describes several nonstationary image artifacts that are present in Kepler data and discusses their impact on photometric precision.…”

Section: Introductionmentioning

confidence: 99%

Flagging and correction of pattern noise in the Kepler focal plane array

et al. 2010

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In order for Kepler to achieve its required <20 PPM photometric precision for magnitude 12 and brighter stars, instrument-induced variations in the CCD readout bias pattern (our "2D black image"), which are either fixed or slowly varying in time, must be identified and the corresponding pixels either corrected or removed from further data processing. The two principle sources of these readout bias variations are crosstalk between the 84 science CCDs and the 4 fine guidance sensor (FGS) CCDs and a high frequency amplifier oscillation on <40% of the CCD readout channels. The crosstalk produces a synchronous pattern in the 2D black image with time-variation observed in <10% of individual pixel bias histories. We will describe a method of removing the crosstalk signal using continuously-collected data from masked and over-clocked image regions (our "collateral data"), and occasionally-collected full-frame images and reverse-clocked readout signals. We use this same set to detect regions affected by the oscillating amplifiers. The oscillations manifest as time-varying moiré pattern and rolling bands in the affected channels. Because this effect reduces the performance in only a small fraction of the array at any given time, we have developed an approach for flagging suspect data. The flags will provide the necessary means to resolve any potential ambiguity between instrument-induced variations and real photometric variations in a target time series. We will also evaluate the effectiveness of these techniques using flight data from background and selected target pixels.

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“…3 The measured gain values for each are given in the Kepler Instrument Handbook and range from 93.5 e − /DN to 120 e − /DN. 4 Using this ground-based data, we have derived a pixel-level linearity correction that is applied during calibration.…”

Section: Gain and Linearitymentioning

confidence: 99%

“…Details of the instrument design, construction and testing are given elsewhere. 1,3,4 Early results from Kepler indicate that the instrument is performing as designed 5 and that we are getting both the photometric precision and the instrument stability necessary to meet Kepler's goals. 6,7 However, the presence of several image artifacts put some parts of the focal plane at risk to achieving the precision needed to find Earth-size transits 5 Detailed descriptions of the image artifacts as well as mitigation steps that have been developed are given elsewhere.…”

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confidence: 99%

Kepler instrument performance: an in-flight update

et al. 2010

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The Kepler Mission is designed to detect the 80 parts per million (ppm) signal from an Earth-Sun equivalent transit. Such precision requires superb instrument stability on time scales up to 2 days and systematic error removal to better than 20 ppm. The sole scientific instrument is the Photometer, a 0.95 m aperture Schmidt telescope that feeds the 94.6 million pixel CCD detector array, which contains both Science and Fine Guidance Sensor (FGS) CCDs. Since Kepler's launch in March 2009, we have been using the commissioning and science operations data to characterize the instrument and monitor its performance. We find that the in-flight detector properties of the focal plane, including bias levels, read noise, gain, linearity, saturation, FGS to Science crosstalk, and video crosstalk between Science CCDs, are essentially unchanged from their pre-launch values. Kepler's unprecedented sensitivity and stability in space have allowed us to measure both short-and long-term effects from cosmic rays, see interactions of previously known image artifacts with starlight, and uncover several unexpected systematics that affect photometric precision. Based on these results, we expect to attain Kepler's planned photometric precision over 90% of the field of view.

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The Kepler photometer focal plane array

Cited by 20 publications

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THE KEPLER-19 SYSTEM: A TRANSITING 2.2R_⊕PLANET AND A SECOND PLANET DETECTED VIA TRANSIT TIMING VARIATIONS

THE KEPLER-19 SYSTEM: A TRANSITING 2.2R_⊕PLANET AND A SECOND PLANET DETECTED VIA TRANSIT TIMING VARIATIONS

Flagging and correction of pattern noise in the Kepler focal plane array

Kepler instrument performance: an in-flight update

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The Kepler photometer focal plane array

Cited by 20 publications

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THE KEPLER-19 SYSTEM: A TRANSITING 2.2R⊕PLANET AND A SECOND PLANET DETECTED VIA TRANSIT TIMING VARIATIONS

THE KEPLER-19 SYSTEM: A TRANSITING 2.2R⊕PLANET AND A SECOND PLANET DETECTED VIA TRANSIT TIMING VARIATIONS

Flagging and correction of pattern noise in the Kepler focal plane array

Kepler instrument performance: an in-flight update

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Product

Resources

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THE KEPLER-19 SYSTEM: A TRANSITING 2.2R_⊕PLANET AND A SECOND PLANET DETECTED VIA TRANSIT TIMING VARIATIONS

THE KEPLER-19 SYSTEM: A TRANSITING 2.2R_⊕PLANET AND A SECOND PLANET DETECTED VIA TRANSIT TIMING VARIATIONS