LATEST RIO-GROUP PUBLICATIONS

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The Rio Group

Since 2005, an international team has been dedicated to the study of distant bodies in the Solar System through stellar occultations. It is led by Dr. Bruno Sicardy, researcher of the Paris-Meudon Observatory, and includes researchers from the Institute of Astrophysics of Andalucia, led by Dr. José Luiz Ortiz and also researchers from Brazil, led by Dr. Roberto Vieira Martins from National Observatory in Rio de Janeiro. The Brazilian team has an infrastructure of LIneA and the support of INCT of e-Universo ...

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Articles

The size, shape, density and ring of the dwarf planet Haumea from a stellar occultation

Haumea—one of the four known trans-Neptunian dwarf planets—is a very elongated and rapidly rotating body1,2,3. In contrast to other dwarf planets4,5,6, its size, shape, albedo and density are not well constrained. The Centaur Chariklo was the first body other than a giant planet known to have a ring system7, and the Centaur Chiron was later found to possess something similar to Chariklo’s rings8,9. Here we report observations from multiple Earth-based observatories of Haumea passing in front of a distant star (a multi-chord stellar occultation). Secondary events observed around the main body of Haumea are consistent with the presence of a ring with an opacity of 0.5, width of 70 kilometres and radius of about 2,287 kilometres. The ring is ...

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Articles

A ring system detected around the Centaur (10199) Chariklo

Hitherto, rings have been found exclusively around the four giant planets in the Solar System1. Rings are natural laboratories in which to study dynamical processes analogous to those that take place during the formation of planetary systems and galaxies. Their presence also tells us about the origin and evolution of the body they encircle. Here we report observations of a multichord stellar occultation that revealed the presence of a ring system around (10199) Chariklo, which is a Centaur—that is, one of a class of small objects orbiting primarily between Jupiter and Neptune—with an equivalent radius of 124??9?kilometres (ref. 2). There are two ...

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