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La temperatura de espín del NH3 en el cometa C/1999S4 (LINEAR)
H Kawakita1, J Watanabe, H Ando
1Gunma Astronomical Observatory, 6860-86 Nakayama, Takayama, Agatsuma, Gunma 377-0702, Japan. kawakita@astron.pref.gunma.jp
Science (New York, N.Y.)
|November 3, 2001
Resumen
La relación orto-para de amoníaco en el cometa C/1999S4 (LINEAR) sugiere que su hielo se formó entre Saturno y Urano. Esto proporciona pistas sobre la nebulosa solar.
Área de la Ciencia:
- La astronomía y la astrofísica.
- Ciencias planetarias Ciencias planetarias.
- Ciencia de los Cometas Ciencia de los Cometas
Sus antecedentes:
- La composición de los cometas ofrece información sobre el sistema solar temprano.
- El amoníaco es un volátil clave en los cometas, originado en la nebulosa solar.
- La relación orto-para (OPR) del amoníaco es un trazador sensible de su temperatura de formación.
Objetivo del estudio:
- Para determinar la relación orto-para (OPR) de NH2 en el cometa C/1999S4 (LINEAR).
- Para inferir la temperatura de formación y la ubicación del hielo de amoníaco cometario.
- Comprender la historia térmica y el origen de los hielos cometarios en la nebulosa solar.
Principales métodos:
- Se obtuvieron espectros ópticos de alta dispersión del cometa C/1999S4 (LINEAR) utilizando el telescopio Subaru.
- Se analizaron las líneas de emisión de NH2 utilizando un modelo de excitación de fluorescencia.
- Calculó la relación orto-para (OPR) y derivó la temperatura de giro del amoníaco.
Principales resultados:
- Un espectro de alta relación señal-ruido produjo líneas precisas de emisión de NH2.
- Se determinó que la relación orto-para (OPR) de NH2 era de 3,33 ± 0,07.
- La temperatura de espín derivada del amoníaco fue de 28 ± 2 Kelvin.
Conclusiones:
- El OPR NH2 refleja el OPR de amoníaco primordial, indicando las condiciones de formación.
- La temperatura de giro derivada sugiere que el hielo de amoníaco cometario se formó entre Saturno y Urano.
- Este hallazgo limita la ubicación de la formación molecular y la condensación en la nebulosa solar temprana.
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