S[CLC]r[/CLC] [CSC]ii[/CSC] and [S[CLC]r[/CLC] [CSC]ii[/CSC]] Emission in the Ejecta of η Carinae

Zethson, T.; Gull, Theodore R.; Hartman, Henrik; Johansson, Sveneric; Davidson, Kris; Ishibashi, Koji

doi:10.1086/321119

Cited by 54 publications

(94 citation statements)

References 11 publications

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“…The model presented by Langer et al (1999) is different in that they consider the ratio of luminosity to the Eddington limit. Similar considerations are qualitatively presented by Zethson et al (1999) to account for the slow ejecta in the equatorial plane of Car. They emphasize that even slowly rotating luminous stars can have highly nonspherical mass-loss geometry.…”

Section: Angg Ular Velocity Evv Olution Duringgthe Great Eruptionsupporting

confidence: 67%

Why a Single‐Star Model Cannot Explain the Bipolar Nebula of η Carinae

Soker

2004

ApJ

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I examine the angular momentum evolution during the 1837-1856 Great Eruption of the massive star Carinae. I find that the new estimate of the mass blown during that eruption implies that the envelope of Car substantially spun down during the 20 yr eruption. Single-star models, most of which require the envelope to rotate at close to the break-up velocity, cannot account for the bipolar nebula-the Homunculus-formed from matter expelled in that eruption. The kinetic energy and momentum of the Homunculus further constrain singlestar models. I discuss how Car can fit into a unified model for the formation of bipolar lobes in which two oppositely ejected jets inflate two lobes (or bubbles). These jets are blown by an accretion disk, which requires stellar companions in the case of bipolar nebulae around stellar objects.

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Section: Angg Ular Velocity Evv Olution Duringgthe Great Eruptionsupporting

confidence: 67%

Why a Single‐Star Model Cannot Explain the Bipolar Nebula of η Carinae

Soker

2004

ApJ

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“…used ground-based data to study ejecta, including the S-condensation, and found evidence for mixing of the nitrogen-rich material with previous mass loss material. The Strontium Filament (Zethson et al 2001;Hartman et al 2004), a neutral emission region located within a few arcsec of Car, has more recently been shown to have overabundances of titanium relative to nickel and iron (Bautista et al 2005). Oxygen, necessary to form oxides that normally lead to titanium precipitation onto dust grains, is not present in quantities sufficient for normal interstellar (IS) dust.…”

Section: Further Demonstrated That Nebular Lines Of [Ne Iii] [Ar IIImentioning

confidence: 99%

Eta Carinae across the 2003.5 Minimum: The Character and Variability of the Ejecta Absorption in the Near‐Ultraviolet

Gull

Kober

Nielsen

2006

ASTROPHYS J SUPPL S

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We present Hubble Space Telescope (HST ) Space Telescope Imaging Spectrograph (STIS) high-resolution nearultraviolet (NUV) spectra of Car's central source recorded before, during and after the 2003.5 spectroscopic minimum. Our focus is on the narrow absorption lines formed in multiple circumstellar shells, superimposed on the broad P Cygni stellar wind features, and how they respond to the flux variations of Car across the minimum. Over 30 separate narrow-line velocity components are identified: three around À146 km s À1 , many between À323 and À587 km s À1 , and a few exceeding À1000 km s À1 . In general, excitation decreases with increasing velocity indicating that the primary excitation is by UV stellar photons and that the slower shells are located closer to the central source. Two well-isolated velocity systems at À146 and À513 km s À1 display very different spectral characteristics regarding ionization/excitation and respond differently to Car's spectroscopic minimum. The À146 km s À1 shell, associated with the (internal ) Little Homunculus, is ionized across the broad spectroscopic maximum but relaxes during the few months long minimum. The À146 km s À1 component is joined by adjacent velocity components in lines of singly ionized iron-group elements. Ti ii and V ii absorptions appear during the minimum, most likely caused by a decrease in Lyman-ionizing flux. The À513 km s À1 component, part of the (outer) Homunculus, does not show significant changes in atomic absorptions, but intermediate-velocity components between À369 and À503 km s À1 vary during the minimum. We present the NUV spectrum and describe its general characteristics, but we focus on identifications of the nebular absorption lines and their variations across the 2003.5 minimum. The complete spectrum between 2380 and 3160 8 with line identifications is available in the electronic edition of this paper.

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“…Barklem & O'Mara 2000;Zethson et al 2001). Most recently, with the aid of these six Sr II lines, NLTE stellar strontium abundances have been derived by serval authors (Andrievsky et al 2011;Bergemann et al 2012).…”

Section: Introductionmentioning

confidence: 99%

Electron-impact broadening parameters for Be II, Sr II, and Ba II spectral lines

Duan

Bari

et al. 2013

A&A

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Aims. We present results of the electron-impact broadening parameters (i.e., widths and shifts) of spectral lines in singly ionized Be II, Sr II, and Ba II ions, calculated by using our relativistic quantum mechanical methods. Methods. In these calculations, Dirac R-matrix methods were used to solve (N + 1)-electron colliding systems to obtain the required scattering matrices. The dimensionless collision strength Ω(ε) is calculated as a function of incident electron energies ε.Results. The present line-broadening parameters are required for future spectral analysis by means of state-of-the-art nonlocal thermodynamic equilibrium atmospheres, which is now hampered largely by the paucity of reliable atomic and accurate line-broadening data tables. Our results for the spectral line-broadening parameters in the case of three ions obtained for a set of electron temperatures at an electron density 10 17 cm −3 show very good agreement with other theoretical calculations, and are much closer to the available experimental measurements.

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S[CLC]r[/CLC] [CSC]ii[/CSC] and [S[CLC]r[/CLC] [CSC]ii[/CSC]] Emission in the Ejecta of η Carinae

Abstract: We have discovered four extremely surprising emission lines of strontium in ejecta near g Carinae.

Cited by 54 publications

References 11 publications

Why a Single‐Star Model Cannot Explain the Bipolar Nebula of η Carinae

Why a Single‐Star Model Cannot Explain the Bipolar Nebula of η Carinae

Eta Carinae across the 2003.5 Minimum: The Character and Variability of the Ejecta Absorption in the Near‐Ultraviolet

Electron-impact broadening parameters for Be II, Sr II, and Ba II spectral lines

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