Um asteroide invulgar
A Fotografia da Semana de hoje mostra diferentes ângulos dum asteróide muito peculiar chamado (44) Nysa. Os asteróides são resíduos da formação dos planetas do Sistema Solar, sendo que a maioria se encontra numa cintura circular entre Marte e Júpiter. Estes corpos rochosos apresentam-se de várias formas e tamanhos, mas novas imagens do (44) Nysa, situado na borda interna da cintura de asteróides, revelam uma estrutura invulgar, diferente de tudo o que já foi observado até agora.
Para determinar a forma de (44) Nysa, uma equipa de astrónomos utilizou o instrumento SPHERE montado no Very Large Telescope (VLT) do ESO, no Chile, e o SHARK-VIS, um instrumento do Instituto Nacional de Astrofísica de Itália instalado no Large Binocular Telescope, nos EUA. Ambos os instrumentos fazem uso de óptica adaptativa para corrigir a distorção atmosférica terrestre e, desse modo, conseguiram obter imagens muito nítidas deste asteróide.
Os dados mostram que o asteróide tem uma dimensão de cerca de 80 km e é composto por três lóbulos distintos, unidos por duas secções mais estreitas. Todas as identificações anteriores de asteróides deste tipo, como é o caso do asteroide (216) Cleopatra, mostraram uma forma de "osso de cão", ou seja, com apenas dois lóbulos, no entanto (44) Nysa apresenta uma estrutura única de três lóbulos.
A equipa apresenta duas explicações possíveis para a forma invulgar de (44) Nysa: ou o asteróide tem origem num único objeto que sofreu forte deformação devido a colisões, ou é composto por três corpos diferentes que colidiram e se fundiram, formando secções mais estreitas nos pontos de contacto.
São necessárias mais observações para podermos esclarecer qual destas hipóteses será a correcta, mas, por agora, os astrónomos estão contentes por terem conseguido determinar a estrutura de (44) Nysa, cuja verdadeira natureza há muito escapava às tentativas de identificação. O asteróide deve o seu nome ao mítico local de nascimento do deus da mitologia grega Dionísio, associado ao vinho, à alegria, à vegetação e ao teatro.
Links
- Artigo científico publicado na revista da especialidade Astronomy & Astrophysics
- Comunicado de imprensa do Lowell Observatory
- Imagens deste timelapse
ESO/K. Minker et al.
Sobre o vídeo
| Id: | potw2631a |
| Língua: | pt |
| Data de divulgação: | 3 de Agosto de 2026 às 06:00 |
| Duração: | 19 s |
| Frame rate: | 25 fps |
Sobre o objeto
| Nome: | (44) Nysa |
| Tipo: | Solar System : Interplanetary Body : Asteroid |
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