Photometry of exoplanetary transits at Osservatorio Polifunzionale del Chianti

L Naponiello,E Pace,E Papini,M Focardi,V Noce,A Biagini,D Trisciani,L Fini,L Betti,M Agostini,R Stanga

doi:10.1007/s10686-020-09669-6

Abstract

In this paper we report the observations of HD189733b, Kepler-41b, Kepler-42b, GJ 436b, WASP-77ab, HAT-P-32b and EPIC 211818569 as measured at the Osservatorio Polifunzionale del Chianti, a new astro-nomical site in Italy. Commissioning observing runs have been done in order to test capabilities, systematics and limits of the system and to improve its accuracy. For this purpose, a software algorithm has been developed to estimate the differential photometric error of any transit observation, so that the integration time can be chosen to reach optimal signal-to-noise ratios, and to obtain a picture of what kind of transits this setup can reveal. Currently, the system is able to reach an accuracy of about 1 mmag and so it is ready for the much needed exoplanetary transit follow-up.

Highlights

The Osservatorio Polifunzionale del Chianti (OPC) is a new astronomical site managed by the University of Florence, whose name takes origin from the different observatories that are hosted in the building
All the observations documented in this paper have been done using the main telescope, which has a focal ratio of F/8 and is supported by a German equatorial mount, while its optical design is based on a Ritchey-Chretien con guration
The main research activity at OPC concerns the detection of transiting exoplanets, and here we report our observations of HD189733b (Bouchy et al 2005), Kepler-41b [1], Kepler-42b [2], GJ 436b [3], WASP-77ab [4], HAT-P-32b [5] and EPIC 211818569 [6], which are well known exoplanets that have been chosen to test the OPC setup for their availability in the needed time frame and the di erent signal-tonoise (S/N) ratio of their transits

Summary

Introduction

The Osservatorio Polifunzionale del Chianti (OPC) is a new astronomical site managed by the University of Florence, whose name takes origin from the different observatories that are hosted in the building. The OPC research staff is involved in national and international collaborations, like GAPS (Global Architecture of Planetary Systems) [7], which exploits several telescopes and facilities in Italy (Asiago, Osservatorio Autonomo della Valle d’Aosta) and Canary Islands (HARPS-North and GIANO instruments as well as their improved combined version installed at the Italian Telescopio Nazionale Galileo) for exoplanetary characterization, and the TESS (Transiting Exoplanet Survey Satellite) SG1 (Sub-group 1) follow-up [8] as well as the KFUN (KELT Follow-up Network) [9] for the observation of exoplanet candidates. By transiting wide-field surveys such as TESS and other coming satellites like PLATO [14] These surveys are built to look at a large number of stars at once, so their pixel scales are larger than the sub-arcsec pixels that ground-based telescopes employ. According to Zellem et al [16] precise mid-transit time predictions would enable space missions to act more efficiently, so much that transit maintenance with a network of sixteen 15 cm aperture telescope could save up to 100 days of ARIEL observing time during its nominal mission lifetime of 3.5 years

Error estimation

Algorithm

Results and conclusions