Porrima — Estrela Dupla em Virgem
HIP 61941; Gamma Virginis; 29 Virginis
Sobre Porrima
Descrição
Porrima, Gamma Virginis, is one of the most famous visual binaries in the sky — a pair of nearly identical F0 V dwarfs in a highly eccentric 169-year orbit. Both stars shine at magnitude 3.5, giving a combined magnitude of 2.7. The system lies just 33 light-years away, making it one of the closest bright visual binaries. Periastron passage in 2005 brought the pair to within 0.4 arcseconds — inseparable even in large amateur telescopes.
Dicas de Observação
In the 2020s the pair has widened to roughly 3-4 arcseconds — comfortable for a 4-inch telescope at 150x. The separation continues to grow, peaking around 2080 before closing again. Both components appear pale yellow-white and nearly equal, making Porrima one of the sky's finest "matched pairs." Find it by following the right-angle formed by Auva, Vindemiatrix, and Spica in southern Virgo. Best observed February through July.
História
Porrima takes its name from a Roman goddess of prophecy, preserved through medieval Latin astronomy. The binary nature was discovered by Bradley and Pound in 1718, and the orbit was first computed by Sir John Herschel in 1833 — making Porrima one of the first stars whose orbital motion proved that gravity operates beyond our solar system. The IAU formally adopted "Porrima" for Gamma Vir A in 2016.
Curiosidades
The periastron of 2005 was one of the most-observed binary events in amateur astronomy of that decade, with hundreds of separation measurements contributed by backyard observers worldwide. The two stars have similar masses (1.56 Suns each) and ages (~1.1 billion years), and they will both eventually evolve to giants roughly together. Sir William Herschel was one of the first to confirm that Porrima's components orbit each other, helping establish that binary stars exist beyond the solar neighborhood.
Observar
1Propriedades Físicas
2Posição e Identificadores
3Facilidade de separação
| Telescópio | Bortle 3 | Bortle 4 | Bortle 5 |
|---|---|---|---|
| Refrator 80 mm Refr. 80mm | Médio+ | Médio+ | Médio+ |
| Newton 150 mm Newt. 150mm | Fácil | Fácil | Fácil |
| Celestron C8 (SCT 203 mm) C8 203mm | Fácil | Fácil | Fácil |
Bortle 3 = rural · 4 = suburbano · 5 = urbano
4Visibilidade
Defina um local nas Configurações do Usuário para ver dados de visibilidade.
5Sistema Estelar Múltiplo Quadruple C,D,E,F: óptico
Separação ao longo do tempo
Separação aparente ao longo do tempo, calculada a partir dos elementos orbitais ORB6. Curvas íngremes indicam pares de rápida evolução — observe-os enquanto forem separáveis.
Vista pela Ocular
A: 3.6 · B: 3.5 · Sep: 3.6″ · PA: 352° · N cima, L direita
Resolvido · Rayleigh: 2.3″ · Dawes: 1.9″ · Eff: 2.3″
Explorar
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Comparação de Tamanho
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Comparar Estrelas
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Classificação Espectral
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Diagrama Hertzsprung-Russell
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Ciclo de vida estelar
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Espectro de corpo negro
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Espectro de absorção estelar
Espectro de absorção simulado com base no tipo espectral. Passe o mouse sobre as linhas para identificar os elementos.
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Fusão Estelar
Descobrir
15Notas Estelares
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Máquina do tempo da luz
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Viagem Relativística
Próximos no céu
Outros alvos a poucos graus — mova um pouco o telescópio e continue explorando.
Os scores de visibilidade assumem um Newton de 150 mm com Bortle 4.
Explore o Nightbase
Conhecimento, ferramentas e histórias relacionadas — sem precisar planejar observação.