2021 occultations and transits of Linus orbiting (22) Kalliope I. Polygonal and cliptracing algorithms

0575156 - ASÚ 2024 RIV FR eng J - Journal Article
Broz, M. - Ďurech, J. - Ferrais, M. - Lee, H. - J. - Kim, M. - J. - Roh, D.G. - Yim, S.-H. - Jehin, E. - Burdanov, A. - De Wit, J. - Fatka, Petr - Hanuš, J. - Carry, B.
2021 occultations and transits of Linus orbiting (22) Kalliope I. Polygonal and cliptracing algorithms.
Astronomy & Astrophysics. Roč. 676, August (2023), č. článku A60. ISSN 0004-6361. E-ISSN 1432-0746
R&D Projects: GA ČR(CZ) Ga21-11058S; GA ČR(CZ) GA23-04946S
Institutional support: RVO:67985815
Keywords : minor planets * planets and satellites * celestial mechanics
OECD category: Astronomy (including astrophysics,space science)
Impact factor: 6.5, year: 2022
Method of publishing: Open access

The satellite Linus orbiting the main-belt asteroid (22) Kalliope exhibited mutual occultation and transit events in late 2021. A photometric campaign was organised and observations were undertaken by the TRAPPIST-South, SPECULOOS-Artemis, OWL-Net, and BOAO telescopes, with the goal to further constrain dynamical and photometric models of this sizeable asteroid-satellite system. Our dynamical model is sufficiently complex, featuring multipoles (up to the order of ℓ = 2), internal tides, and external tides. The model was constrained by astrometry (spanning 2001-2021), occultations, adaptive-optics imaging, and calibrated photometry, as well as relative photometry. Our photometric model was substantially improved. A new precise (<0.1 mmag) light curve algorithm was implemented, based on polygon intersections, which are computed exactly by including partial eclipses and partial visibility of polygons. Moreover, we implemented a `cliptracing' algorithm, again based on polygon intersections, in which partial contributions to individual pixels are computed exactly. Both synthetic light curves and synthetic images then become very smooth.
Permanent Link: https://hdl.handle.net/11104/0345738