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THE PHOTOMETRY GROUP. Team leaders : Aleksandar Cikota Dijana Vrbanec. Team members : Ivana Barišić Dino Bektešević Neven Golenić Lucija Šabarić. Introduction.
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THE PHOTOMETRY GROUP Teamleaders: Aleksandar Cikota Dijana Vrbanec Teammembers: Ivana Barišić Dino Bektešević Neven Golenić LucijaŠabarić
Introduction • Photometry is a procedure of measuringvisiblelight in unitsthat are weightedaccording to thesensitivity of the human eye • Variables - starsthat change theirbrightness • Some starsvary in brightnessbecause of physicalchanges, such as pulsations or eruptions and theothersvary in lightoutputdue to eclipses or stellarrotation
Ouraims • Reduce 20Gb of datafromTelAvivObservatory and searchforvariablestars (18 nights) • Plot lightcurves of all stars(35 000) • Check all thelightcurvesforvariablestars • Determingifthosestars are unknown • Photometry in Canopus • Approximately determine variable stars types • Photometry of an exoplanet • Check mira stars
Python • learningbasics of Python • writing a scriptforsortingimages
MaxIm DL • calibratingphotos of variablestars
Plot script in Python • manipulatesdatacreatedbythephotometryscriptand createsgraphicalpreview of numericdata
Variable stars plots • We checked all the plots (35 000) • Found 80 variable stars
Output data • Scriptthatprintsoutrightascension, declination, and magnitude
AAVSO • American association of variable stars observers • Web page that contains a list of variable stars • www.aavso.org contains VSX
Canopus • Program forplotting • preciselightcurves • User is able to read • time, magnitude, and • derived period
Exoplanet XO-2 • Exoplanet orextrasolarplanet is a planet that evolvesaroundother star (notSun) • There are severalways of detectingexoplanets: - thetransitphotometrymethod – our method - thespectroscopicmethod - astrometrymethod - gravitylensing
198 photos of XO-2 taken in thenight of 07/03/2009 fromLaSagraobservatory • a lot of noise on imagesbecause of badweather • Plottinglightcurve in Canopus • Determining all orbitalparameters of theextrasolar planet XO-2 fromit’s lightcurve
Mira variables • search for new LPV-s (long period variables or mira (ο Ceti) stars) that were considered as potential miras in VišnjanObservatorydatabase • Check in otherdatabases • Python- extracting star names and coordinatesfromVišnjanObservatorymira database list • Search in SDSS and SIMBAD
Future goals • To publish new variablestarsthat we havefound and theirlightcurves in JAAVSO (Journal of the AAVSO) • Finishthesearchfor new mira variables