Anomalous Fe II Spectral Effects and High H I Lyα Temperature in Gas Blobs Near η Carinae

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Anomalous Fe II Spectral Effects and High H I Lyα Temperature in Gas Blobs Near η Carinae. / Johansson, Sveneric; Letokhov, Vladilen.

I: Astronomy Letters, Vol. 30, Nr. 1, 2004, s. 58-63.

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Johansson, Sveneric ; Letokhov, Vladilen. / Anomalous Fe II Spectral Effects and High H I Lyα Temperature in Gas Blobs Near η Carinae. I: Astronomy Letters. 2004 ; Vol. 30, Nr. 1. s. 58-63.

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TY - JOUR

T1 - Anomalous Fe II Spectral Effects and High H I Lyα Temperature in Gas Blobs Near η Carinae

AU - Johansson, Sveneric

AU - Letokhov, Vladilen

PY - 2004

Y1 - 2004

N2 - 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.

AB - 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.

U2 - 10.1134/1.1647477

DO - 10.1134/1.1647477

M3 - Article

VL - 30

SP - 58

EP - 63

JO - Astronomy Letters

JF - Astronomy Letters

SN - 1063-7737

IS - 1

ER -