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Descubrimiento de jóvenes y aislados objetos de masa planetaria en el cúmulo estelar sigma final Orionis
M R Zapatero Osorio1, V J Béjar, E L Martín
1Instituto de Astrofísica de Canarias, E-38200 La Laguna, Tenerife, Spain.
Science (New York, N.Y.)
|October 6, 2000
Resumen
Los astrónomos han descubierto planetas gigantes aislados en el joven cúmulo de sigma Orionis. Estos objetos flotantes, similares en masa a Júpiter, desafían las teorías actuales de la formación de planetas.
Área de la Ciencia:
- La astronomía y la astrofísica.
- Investigación de exoplanetas Investigación de exoplanetas
- Evolución Estelar Evolución Estelar
Sus antecedentes:
- El cúmulo de sigma Orionis es una asociación estelar cercana (352 parsecs), joven (1-5 millones de años).
- Su baja extinción interna proporciona una visión clara de los objetos subestelares.
- El cúmulo alberga múltiples estrellas masivas, que influyen en su entorno.
Objetivo del estudio:
- Descubrir y caracterizar objetos aislados de luminosidad extremadamente baja dentro del cúmulo sigma Orionis.
- Para explorar el dominio subestelar hasta unas pocas masas de Júpiter.
- Para investigar los procesos de formación de objetos de masa planetaria.
Principales métodos:
- Imágenes ópticas e infrarrojas cercanas para identificar objetos aislados y rojos.
- Espectroscopia de baja resolución para determinar la distribución de energía espectral y las temperaturas atmosféricas.
- Estimación de masa basada en las características espectrales y la pertenencia al clúster.
Principales resultados:
- Descubrimiento de una población extremadamente roja y de baja luminosidad de objetos aislados.
- Confirmación espectroscópica de temperaturas efectivas atmosféricas muy frías (1700-2200 K).
- Las masas estimadas para tres objetos oscilan entre 5 y 15 masas de Júpiter.
Conclusiones:
- Estos objetos representan una nueva clase de planetas gigantes aislados, no unidos a ninguna estrella.
- Su aparente formación en unos pocos millones de años desafía los modelos existentes de formación de planetas.
- Los hallazgos requieren una reevaluación de cómo se forman los objetos de masa planetaria en los cúmulos estelares.
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