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A light curve of the eclipsing binary CM Draconis has been analyzed for the presence of transits of planets of size º2.5 Earth radii with periods of 60 days or less, and in coplanar orbits around the (R E ), binary system. About 400 million model light curves, representing transits from planets with periods ranging from 7 to 60 days, have been matched/correlated against these data. This process we call the "" transit detection algorithm ÏÏ or TDA. The resulting "" transit statistics ÏÏ for each planet candidate allow the quantiÐcation of detection probabilities, and of false-alarm rates.Our current light curve of CM Dra has a coverage of 1014 hr with 26,043 individual points, at a photometric precision between 0.2% and 0.7%. Planets signiÐcantly larger than would constitute a 3R E "" supranoise ÏÏ detection, and for periods of 60 days or less, they would have been detected with a probability greater than 90%. "" Subnoise ÏÏ detections of smaller planets are more constrained. For example, planets with 10 day periods or less would have been detected with an 80% probability. The neces-2.5R E sity for predicted observations is illustrated with the nine top planet candidates that emerged from our TDA analysis. They are the planet candidates with the highest transit statistics from the 1994È1998 observing seasons, and for them transits for the 1999 observing season were predicted. Of the seven candidates that were then observationally tested in 1999, all were ruled out except one, which needs further observational conÐrmation. We conclude that the photometric transit method is a viable way to search for relatively small, inner extrasolar planets with moderate-sized telescopes using CCD photometry with a matching-Ðlter analysis.

Inter-pixel capacitive coupling can exist in a non-destructive detector array if the detector nodes change voltage as they integrate charge and the design of the device allows for an electric field to exist between adjacent collection nodes. Small amounts of inter-pixel capacitance can cause large errors in the measurement of poissonian noise versus signal, and all subsequently derived measurements such as nodal capacitance and quantum efficiency. Crosstalk and MTF can also be significantly influenced by interpixel capacitance. Two 1k × 1k Raytheon SB226-based hybridized silicon PIN arrays were tested for nodal capacitance and MTF. Initial results indicated unexpected and unexplainably large nodal capacitance, poor MTF, and odd edge spread. It was hypothesized that inter-pixel capacitive coupling was responsible for these discrepancies. A stochastic method of measuring the coupling using 2D autocorrelation and Fourier Transform techniques was devised and implemented. Autocorrelation of the shot noise in the images revealed a correlation consistent with 3.2% interpixel capacitive coupling. When the effects of the measured interpixel capacitance were taken into account, the initially measured nodal capacitance of 56 fF was found to be 30% higher than the corrected nodal capacitance measurement of 43 fF. Large discrepancies between the theoretical and observed edge spread response were also greatly reduced. A simulation of the electric field in the PIN detector intrinsic region predicted an interpixel coupling very close to the observed coupling. Interpixel capacitance was also observed in 2k × 2k Raytheon SB304-based InSb detector arrays, but was not strongly evident in a bare Raytheon SB226 multiplexer.

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ABSTRACT.A small CCD photometer dedicated to the detection of extrasolar planets has been developed and put into operation at Mount Hamilton, California. It simultaneously monitors 6000 stars brighter than 13th magnitude in its 49 deg 2 field of view. Observations are conducted all night every clear night of the year. A single field is monitored at a cadence of eight images per hour for a period of about 3 months. When the data are folded for the purpose of discovering low-amplitude transits, transit amplitudes of 1% are readily detected. This precision is sufficient to find Jovian-size planets orbiting solar-like stars, which have signal amplitudes from 1% to 2% depending on the inflation of the planet's atmosphere and the size of the star. An investigation of possible noise sources indicates that neither star field crowding, scintillation noise, nor photon shot noise are the major noise sources for stars brighter than visual magnitude 11.6.Over one hundred variable stars have been found in each star field. About 50 of these stars are eclipsing binary stars, several with transit amplitudes of only a few percent. Three stars that showed only primary transits were examined with high-precision spectroscopy. Two were found to be nearly identical stars in binary pairs orbiting at double the photometric period. Spectroscopic observations showed the third star to be a high mass ratio single-lined binary. On 1999 November 22 the transit of a planet orbiting HD 209458 was observed and the predicted amplitude and immersion times were confirmed. These observations show that the photometer and the data reduction and analysis algorithms have the necessary precision to find companions with the expected area ratio for Jovian-size planets orbiting solar-like stars.

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Subfeatures < 0.5% of continuum were detected moving through the line profiles of the Be/shell star y Cas over a nine-month period in 1983. While the average spacing and acceleration of the subfeatures is consistent with nonradial pulsation of \m\ = 12 ± 4, large variations in the acceleration of the subfeatures are sometimes seen and some subfeatures appear and disappear suddenly. The subfeatures appeared particularly chaotic on 1983 October 26, five days prior to detection of a strong X-ray flare with the Tenma satellite. The observed period of the subfeature oscillations varies between 7000 and 10,000 seconds which is similar to the transient 6000-second variation in X-ray flux found by EXOSAT in December 1984. No rapid E/C variation is observed in the Hy and He I X5876 emission-line profiles.