Zero-phase angle taxonomy classification using unsupervised machine learning algorithms

• Autores: Colazo, Milagros Rita; Alvarez Candal, Alvaro Augusto; Duffard, R.
• Año de publicación: 2022
• Idioma: inglés
• Tipo de recurso: artículo
• Materia: METHODS: DATA ANALYSIS; MINOR PLANETS, ASTEROIDS: GENERAL; SURVEYS; TECHNIQUES: PHOTOMETRIC
• Institución: Consejo Nacional de Investigaciones Científicas y Técnicas

Context. We are in an era of large catalogs and, thus, statistical analysis tools for large data sets, such as machine learning, play a fundamental role. One example of such a survey is the Sloan Moving Object Catalog (MOC), which lists the astrometric and photometric information of all moving objects captured by the Sloan field of view. One great advantage of this telescope is represented by its set of five filters, allowing for taxonomic analysis of asteroids by studying their colors. However, until now, the color variation produced by the change of phase angle of the object has not been taken into account. Aims. In this paper, we address this issue by using absolute magnitudes for classification. We aim to produce a new taxonomic classification of asteroids based on their magnitudes that is unaffected by variations caused by the change in phase angle. Methods. We selected 9481 asteroids with absolute magnitudes of Hg, Hi and Hz, computed from the Sloan Moving Objects Catalog using the HG∗12 system. We calculated the absolute colors with them. To perform the taxonomic classification, we applied a unsupervised machine learning algorithm known as fuzzy C-means. This is a useful soft clustering tool for working with data sets where the different groups are not completely separated and there are regions of overlap between them. We have chosen to work with the four main taxonomic complexes, C, S, X, and V, as they comprise most of the known spectral characteristics. Results. We classified a total of 6329 asteroids with more than 60% probability of belonging to the assigned taxonomic class, with 162 of these objects having been characterized by an ambiguous classification in the past. By analyzing the sample obtained in the plane Semimajor axis versus inclination, we identified 15 new V-type asteroid candidates outside the Vesta family region.
Fil: Colazo, Milagros Rita. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Astronomía Teórica y Experimental. Universidad Nacional de Córdoba. Observatorio Astronómico de Córdoba. Instituto de Astronomía Teórica y Experimental; Argentina
Fil: Alvarez Candal, Alvaro Augusto. Instituto de Astrofisica de Andalucia; España. Ministério de Ciencia, Tecnologia e Innovacao. Observatorio Nacional; Brasil. Universidad de Alicante; España
Fil: Duffard, R.. Universidad de Alicante; España. Instituto de Astrofisica de Andalucia; España