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The scope of the project 'A PSF-based Approach to TESS High Quality data Of Stellar clusters' (PATHOS) is the extraction and analysis of high-precision light curves of stars in stellar clusters and young associations for the identification of candidate exoplanets and variable stars. The cutting-edge tools used in this project allow us to measure the real flux of stars in dense fields, minimizing the effects due to contamination by neighbour sources. We extracted about 200 000 light curves of stars in 645 open clusters located in the Southern ecliptic hemisphere and observed by TESS during the first year of its mission. We searched for transiting signals and we found 33 objects of interest, 11 of which are strong candidate exoplanets. Because of the limited SNR, we did not find any Earth or super-Earth. We identified two Neptune-size planets orbiting stars with |$R_{\star }\lt 1.5\, \mathrm{\it R}_{\odot }$|⁠ , implying a frequency |$f_{\star }=1.34 \pm 0.95\, {{\ \rm per\ cent}}$|⁠ , consistent with the frequency around field stars. The seven Jupiter candidates around stars with |$R_{\star }\lt \, 1.5\, \mathrm{\it R}_{\odot }$| imply a frequency |$f_{\star }=0.19\pm 0.07\, {{\ \rm per\ cent}}$|⁠ , which is smaller than in the field. A more complete estimate of the survey completeness and false positive rate is needed to confirm these results. Light curves used in this work will be made available to the astronomical community on the Mikulski Archive for Space Telescope under the project PATHOS. [ABSTRACT FROM AUTHOR]

The TESS mission will survey ∼85  per cent of the sky, giving us the opportunity of extracting high-precision light curves of millions of stars, including stellar cluster members. In this work, we present our project 'A PSF-based Approach to TESS High quality data Of Stellar clusters' (PATHOS), aimed at searching and characterize candidate exoplanets and variable stars in stellar clusters using our innovative method for the extraction of high-precision light curves of stars located in crowded environments. Our technique of light-curve extraction involves the use of empirical point spread functions (PSFs), an input catalogue and neighbour-subtraction. The PSF-based approach allows us to minimize the dilution effects in crowded environments and to extract high-precision photometry for stars in the faint regime (G > 13). For this pilot project, we extracted, corrected, and analysed the light curves of 16 641 stars located in a dense region centred on the globular cluster 47 Tuc. We were able to reach the TESS magnitude T ∼ 16.5 with a photometric precision of |${\sim} 1{{\ \rm per\ cent}}$| on the 6.5-h time-scale; in the bright regime we were able to detect transits with depth of ∼34 parts per million. We searched for variables and candidate transiting exoplanets. Our pipeline detected one planetary candidate orbiting a main-sequence star in the Galactic field. We analysed the period–luminosity distribution for red-giant stars of 47 Tuc and the eclipsing binaries in the field. Light curves are uploaded on the Mikulski Archive for Space Telescopes under the project PATHOS. [ABSTRACT FROM AUTHOR]