ABSTRACT

1. WASP0: A wide field CCD search for extra solar planets. Instrumentation, data analysis and preliminary results D. Mislis1, S. Pyrzas1, E. Harlaftis2,†, R. A. Street3, K. Horne4, D. Pollacco3, J. H. Seiradakis1, S. R. Kane4, T. Lister4, A. Collier Cameron4, W.I. Clarkson4 1 University of Thessaloniki, Department of Physics, Section of Astrophysics, Astronomy and Mechanics, GR-541 24 Thessaloniki, Greece 2 National Observatory of Athens, Institute of Space Applications and Remote Sensing, P.O. Box 20048, GR-11810 Athens, Greece 3 Queen's University of Belfast, School of Physics, APS Division, Belfast, BT7 1NN, UK 4 University of St Andrews, School of Physics & Astronomy, North Haugh, St Andrews, Fife, KY16 9SS, UK † Passed away, 13 February 2005 To the memory of Emilios ABSTRACT PLANET HUNTING We present the observing strategy, the method of analysis and first results from the WASP0-project, with data taken at the Kryonerion Astronomical Station of the National Observatory of Athens, in 2002. WASP0 (Wide Angle Search for Planets) is a project aiming to discover extrasolar planets using the transit method. Besides extrasolar planets, the project is suitable for detecting new variable stars, novae, asteroids, etc. For the reduction we used the 'SuperWASP pipeline' developed for this specific purpose by the University of St. Andrews and Queens University, UK, with in situ modifications for our computing facilities. We search for planets using the Hunter3 code developed for this project. The code fits a number of models to the data., searching a four dimensional space, parametrized by (a) the position of the event, the duration, the depth of the transit and the slope of the transit curve. We fit all possible theoretical transit models in the light curves of all 25 000 stars in the field and compare the standard deviation of the data before and after subtracting the fitted curve. If the standard deviation is below a certain threshold, we call it a suspect-transit. Then we fit the same model to the light curves from the same star in other nights. If in one more night we find a suspect-transit with the same model, we call it real transit. In this way, we perform 7.1 trillion different combinations in the light curves of the stars in our field. In order to test our technique and the Hunter3 code, we observed and detected the well known planet, HD209458, under full moon conditions. OBSERVATIONS AND… The observations were undertaken at Kryonerion Astronomical Station, Greece, with the WASP0 Instrument. WASP0 is a wide-field (9°), 6.3cm aperture F/2.8 Nikon camera lens, equipped with an Apogee-10 CCD detector. The detector is a 2K×2K chip with 16″ pixels, built by Don Pollacco at Queen's University, Belfast. The Hyades Open Cluster was observed for 20 nights over a period of three months in winter 2002. The observed field contained about 25 000 stars to the limiting magnitude of our equipment. Between 80 and 120 photographs were taken every night, depending on the weather conditions. HD209458 FIRST STAGE ANALYSIS We used the Super Wasp pipeline to reduce the data. The pipeline estimates the fluxes, coordinates, standard deviation, RMS errors and air-mass of each star in the field. Apogee 10 CCD from Kryonerion Observatory (Greece) VARIABLE STARS IN THE HYADES FIELD The variable stars exhibit the highest standard deviation among all stars. Therefore, they are easily detected by studying the stars with the highest standard deviation. We have discovered about 10 new variable stars up to now, none of which appear in the SIMBAD database. We have studied both the light curves and the periodograms of the new stars, some of which are shown below. The analysis is still underway. A new extra solar planet? A NEW EXTRA SOLAR PLANET? Data for the suspected new extra solar planet in the Hyades open cluster This graphs above show the first suspect planets discovered by the transit method from observations with the WASP0 camera from Greece. The transit was found in two nights. The time between the two transits define the period (or multiples of the period). It was not detected in the data of other nights. This sets rigid constraints to the period of the transit. If it is a real extra solar planetary system, we can derive some useful information about the system. Name : lc1110-0049570 RA: 04h 14m 05.09s Dec: +21° 02´ 37.15´´ Radius 3.21 RJ Period: 4.956 days Depth of transit: 0.021 mag Duration of Transit: 32 min Radius of orbit: 0.0826 AU Inclination of orbit, i : 82.35° Possibility of transit detection: 6.7% Velocity: 181.93 km/s RMS vs Mean Magnitude from Hyades field. The variable stars are those with the highest distance from average linear plot We present the light-curves of 3 new variable stars in the Hyades open cluster and the periodogramms of 2 of them. In the graph to the left, the light curve of a new Algol-type (binary) system is presented. In the bottom graphs the light curves and the periodograms of two δ-Scuti type stars is depicted. FUTURE WORK We plan to investigate the suspect extra solar planet, using small or medium size telescopes, equipped with more sensitive detectors and, in particular, with spectroscopic capabilities. Following these first results from the WASP0 prototype, we plan to continue working towards the detection of new variable stars and extra solar planets. We shall try to make the Hunter3 code more intelligent to fit planet transits with higher probability to detect physical planetary systems. We shall apply it in data that we already have from the SUPER WASP and WASP0 archive. ACKNOWLEDGMENTS The authors would like to thanks D.J. Christian (Belfast (Open University), N.A. Evans (Keele), A. Fitzsimmons (Belfast), C.A. Haswell (Open University), C. Hellier (Keele), S.T. Hodgkin (Cambridge), F.P. Keenan (Belfast), A.J. Norton (Open University), R. Ryans (Belfast), I. Skillen (ING) , R.G. West (Leicester), P.J. Wheatley (Leicester), V. Manimanis and K. Gazeas (University of Athens), K. Stathoulis (Financial Technologies SA , Athens), G. Dimou (National Observatory of Athens), E. & H. Haralabidi (Thessaloniki)