2026-07-29 アリゾナ大学
Adaptive-optics observations obtained with the Large Binocular Telescope’s SHARK-VIS instrument reveal the unusual shape of asteroid (44) Nysa. Kate Minker et al.
＜関連情報＞
- https://news.arizona.edu/news/three-lobed-asteroid-world-unlike-any-other
- https://arxiv.org/abs/2607.25786
（44）ニサの正体解明：三葉構造の証拠 Unmasking (44) Nysa: Evidence for a trilobate structure
Kate Minker, Anthony Berdeu, Gianluca Li Causi, Josef Hanuš, Michaël Marsset, Al Conrad, Fernando Pedichini, Simone Antoniucci, Piero Vaccari, Nick Moskovitz, Benoit Carry, Tom Polakis, Marin Ferrais, Emmanuël Jehin, Roberto Bonamico, Rhiannon Hicks, Daejhanae Smith, M. Amine Miftah, Ester Marini
arXiv Submitted on 28 Jul 2026
DOI:https://doi.org/10.48550/arXiv.2607.25786
Abstract
Context. (44) Nysa is one of the largest known E-type asteroids. Light curve inversion models have indicated that it may have an elongated shape commonly found in large binary systems. Aims. We aimed to identify the morphology and presence of possible satellites orbiting Nysa. Methods. We observed Nysa with the visible-wavelengths adaptive-optics instruments SHARK-VIS and SPHERE/ZIMPOL in order to image the object with the highest possible spatial resolution, and visually identified surface features on the object. A shape model was constructed from these images and photometric light curves using the ADAM code. Results. Imaging revealed a highly unusual morphology with multiple distinct surface features, including two distinct valleys most easily interpreted as colli. A faint satellite was identified in the deconvolution residuals in multiple datasets. Conclusions. We determine that (44) Nysa is a binary system most likely consisting of a contact-trinary or highly-irregular, coherent primary object and a small satellite.
