Anomalous Fe II Spectral Effects and High H I Lyα Temperature in Gas Blobs Near η Carinae
Johansson, Sveneric; Letokhov, Vladilen (2004). Anomalous Fe II Spectral Effects and High H I Lyα Temperature in Gas Blobs Near η Carinae. Astronomy Letters, 30, (1), 58 - 63
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Published
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English
Authors:
Johansson, Sveneric
;
Letokhov, Vladilen
Department:
Lund Observatory - Has been reorganised
Abstract:
We consider the origin of the anomalously high intensity of theultraviolet Fe II lambda 2507/2509 A lines observed with high spatialand spectral resolutions from gas blobs (GBs) near Carinae. This rareeffect in stellar spectra is attributable to a combination of severalfactors: (1) the high hydrogen density (>10^{8} cm^{-3}) that ensuresthe blocking of the Lyman continuum by GBs and, accordingly, theformation of a cold H I region with completely ionized Fe atoms; (2) thesmall distance between the GBs and the central star that ensures a high(>8000-10 000 K) Ly_alpha H spectral temperature, which photoexcitesFe II selectively; and (3) the population of Fe II levels and,accordingly, the opening of a stimulated emission channel, whichtogether with spontaneous transitions creates a radiative cycle where asingle Fe II ion can multiply absorb Ly_alpha emission.
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