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Una estrella muy ampliada con desplazamiento al rojo de 6.2
Brian Welch1, Dan Coe2,3,4, Jose M Diego5
1Center for Astrophysical Sciences, Department of Physics and Astronomy, The Johns Hopkins University, Baltimore, MD, USA. bwelch7@jhu.edu.
Nature
|March 31, 2022
Resumen
Los astrónomos descubrieron una estrella distante y magnificada usando lentes gravitacionales de un cúmulo de galaxias. Esta estrella persistente y altamente magnificada ofrece una oportunidad única para estudiar las poblaciones estelares del universo primitivo.
Área de la Ciencia:
- Cosmología y Astrofísica
- Lentes gravitacionales
- Investigación de exoplanetas
Sus antecedentes:
- Los cúmulos de galaxias actúan como poderosas lentes gravitacionales, magnificando los objetos de fondo.
- Las fuertes lentes gravitacionales pueden estirar las galaxias en arcos y aumentar significativamente el brillo de las fuentes de fondo.
- Los descubrimientos anteriores de estrellas con lentes estaban en desplazamientos al rojo más bajos y exhibieron efectos de microlentes temporales.
Objetivo del estudio:
- Para reportar el descubrimiento y la caracterización de una estrella distante, persistentemente magnificada.
- Investigar las propiedades de las estrellas en el universo primitivo a través de una ampliación extrema.
- Para confirmar el papel de los cúmulos de galaxias en permitir la observación de objetos débiles y distantes.
Principales métodos:
- Utilizado lente gravitacional por el cúmulo de galaxias WHL0137-08 para ampliar una estrella de fondo.
- Se emplearon cuatro modelos de lentes independientes para estimar el factor de aumento.
- Se realizaron imágenes a largo plazo y observaciones de seguimiento durante 3,5 años para evaluar la constancia de brillo.
Principales resultados:
- Descubrió una estrella con un desplazamiento al rojo de 6.2 (900 millones de años después del Big Bang), ampliada por un factor de miles.
- Observado aumento y brillo persistentes (magnitud AB 27.2) durante 3,5 años, a diferencia de las estrellas microlentes transitorias.
- Se calculó una magnitud UV absoluta diluida de -10 ± 2, consistente con una estrella masiva (> 50 masas solares).
Conclusiones:
- Este descubrimiento demuestra el potencial de las lentes gravitacionales para revelar estrellas masivas en el universo primitivo.
- La naturaleza persistente de la ampliación proporciona un objetivo estable para un estudio detallado.
- Se espera que más observaciones con el Telescopio Espacial James Webb confirmen la clasificación y las propiedades espectrales.
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