VLTI revisita a maior estrela hipergigante amarela descoberta até à data
Pode não parecer grande coisa, mas esta mancha gorda mostra a notável estrela chamada V766 Centauri (V766 Cen) e a sua companheira próxima. Esta estrela foi estudada e classificada pela primeira vez há alguns anos atrás por investigadores que usaram o Interferómetro do Very Large Telescope do ESO (VLTI), quando se descobriu que este objeto era uma hipergigante amarela, um tipo extremamente raro de estrela muito massiva e luminosa e extremamente grande! Com mais de 1400 vezes o diâmetro do Sol, a V766 Cen não é apenas a maior estrela do seu tipo descoberta até à data, é também uma das dez maiores alguma vez descobertas.
No entanto, um estudo recente sugeriu que a V766 Cen estaria na fase anterior à de uma hipergigante amarela: uma supergigante vermelha evoluída a perder massa tão depressa que eventualmente fará de novo a transição para uma supergigante amarela mais quente durante um curto período de tempo. De qualquer modo, esta estrela é um verdadeiro monstro e de grande interesse para os cientistas que querem saber mais sobre esta fase invulgar do ciclo de vida das estrelas.
Uma equipa de astrónomos usou de novo o VLTI para estudar a V766 Cen com maior detalhe. Usando a rede dos quatro Telescópios Auxiliares e um instrumento montado no VLTI chamado PIONER (Precision Integrated-Optics Near-infrared Imaging ExpeRiment), a equipa obteve imagens de grande precisão da V766 Centauri e da sua companheira. Os cientistas descobriram que esta companheira é mais pequena e mais fria que a sua parceira — provavelmente uma gigante ou supergigante fria com um raio de cerca de 650 vezes o do Sol. Pensa-se que as estrelas massivas têm tipicamente companheiras próximas, as quais desempenham um papel importante nos processos de evolução estelar.
Ests Fotografia da Semana mostra a V766 Cen vista em três períodos de tempo diferentes. Na realidade, as imagens contêm tanto a V766 Cen como a sua companheira — na primeira imagem a companheira passa por trás da V766 Cen, mas na segunda e terceira imagens a companheira está a passar em frente e pode ser vista como uma mancha brilhante.
Links
Créditos:ESO/M. Wittkowski (ESO)
Sobre a imagem
| Id: | potw1740a |
| Língua: | pt |
| Tipo: | Montagem |
| Data de divulgação: | 2 de Outubro de 2017 às 06:00 |
| Tamanho: | 984 x 416 px |
Sobre o objeto
| Nome: | HR 5171 |
| Tipo: | Milky Way : Star : Evolutionary Stage : Red Supergiant Milky Way : Star : Grouping : Binary |
| Distância: | 12000 anos-luz |
Formatos de imagens
Papéis de parede
Cores e filtros
| Banda | Comprimento de onda | Telescópio |
|---|---|---|
| Infravermelho | 1.59 μm | Very Large Telescope Interferometer PIONIER |
| Infravermelho | 1.58 μm | Very Large Telescope Interferometer PIONIER |
| Infravermelho | 1.58 μm | Very Large Telescope Interferometer PIONIER |
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