Time variations of the narrow Fe II and H I spectral  emission lines from the close 
vicinity of <i>η</i> Carinae  during the spectral event of 2003

Context. The Si III] 1892 Å intercombination line shows an anomalously high intensity in spectra of the radiation-rich Weigelt blobs in the vicinity of Eta Carinae. The line disappears during the 100 days long spectral events occurring every 5.5 years. Aims. The aim is to investigate whether resonance-enhanced two-photon ionization (RETPI) is a plausible excitation mechanism for the Si III] λ1892 line. Methods. The possible intensity enhancement of the λ1892 line is investigated as regards quasi-resonant intermediate energy levels of Si II.Results. The RETPI mechanism is effective on Si ii in the radiation-rich Weigelt blobs where the two excitation steps are provided by the two intense hydrogen lines Lyα and Lyγ.

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“…The same effect was observed during the spectral event (Hartman et al 2005). This fact suggests that the excitation of the…”

Section: Striking Spectral Feature: the 1892 å Si Iii] Intercombinatisupporting

confidence: 76%

Resonance-enhanced two-photon ionization (RETPI) of Si II and an anomalous, variable intensity of the $\mathsf{\lambda}$1892 Si III] line in the Weigelt blobs of η Carinae

Johansson

Hartman

Letokhov

2006

A&A

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“…′′ 5 from the central star that were resolved by early speckle interferometry techniques (Weigelt & Ebersberger 1986;Weigelt et al 1995) and in high-resolution IR images (Chesneau et al 2005). These nebular knots have very strong narrow atomic emission lines throughout the UV, optical, and near-IR spectrum (Davidson et al , 1997Smith 2002;Smith et al 2004a;Hartman et al 2005). Proper motions show that the Weigelt knots and some of the other features are younger than the polar lobes (Dorland et al 2004;Smith et al 2004a), having been ejected in the 1890 eruption or later.…”

Section: Near-ir H2 Emission and Kinematic Structurementioning

confidence: 98%

A disrupted molecular torus around Eta Carinae as seen in 12CO with ALMA

Smith

Ginsburg

Bally

2017

Monthly Notices of the Royal Astronomical Society

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We present Atacama Large Millimeter Array (ALMA) observations of 12 CO 2−1 emission from circumstellar material around the massive star η Carinae. These observations reveal new structural details about the cool equatorial torus located ∼4000 au from the star. The CO torus is not a complete azimuthal loop, but rather, is missing its near side, which appears to have been cleared away. The missing material matches the direction of apastron in the eccentric binary system, making it likely that η Car's companion played an important role in disrupting portions of the torus soon after ejection. Molecular gas seen in ALMA data aligns well with the cool dust around η Car previously observed in mid-infrared (IR) maps, whereas hot dust resides at the inner surface of the molecular torus. The CO also coincides with the spatial and velocity structure of near-IR H 2 emission. Together, these suggest that the CO torus seen by ALMA is actually the pinched waist of the Homunculus polar lobes, which glows brightly because it is close to the star and warmer than the poles. The near side of the torus appears to be a blowout, associated with fragmented equatorial ejecta. We discuss implications for the origin of various features northwest of the star. CO emission from the main torus implies a total gas mass in the range of 0.2 -1 M ⊙ (possibly up to 5 M ⊙ or more, although with questionable assumptions). Deeper observations are needed to constrain CO emission from the cool polar lobes.

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“…The Weigelt blobs are close-in ejecta located at ∼0.1-0.3 arcsec of the star, moving at ∼ -40 km s −1 near the orbital plane (Weigelt & Ebersberger 1986). These clumps are partially ionized and exhibit rapidly varying spectral features modulated by the orbital cycle (Hartman et al 2005;Johansson et al 2006). The ejection of the blobs took place at some point between 1880 and 1930 (Weigelt & Kraus 2012).…”

Section: Introductionmentioning

confidence: 99%

The peculiar chemistry of the inner ejecta of Eta Carina

Bordiu

Rizzo

2019

Monthly Notices of the Royal Astronomical Society

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We investigated continuum and molecular line emission of four species (CO, HCN, H 13 CN, and HCO + ) at 0.8 mm in the inner region around η Car, using ALMA archival observations at a resolution better than 0.2 arcsec. We report the discovery of an asymmetric extended structure northwest of the star, independent from the continuum point source. The structure is only traced by continuum and HCO + , and not detected in the other lines. Kinematics of this structure reveal that the HCO + gas likely arises from ejecta expelled in the 1890s eruption. The ejecta is propagating outward within the cavity produced by the current wind-wind interaction of η Car A and its companion. Chemical analysis of the ejecta reveals an apparent lack of CO and nitrogen-bearing species. We explore possible explanations for this peculiar chemistry, that differentiates this structure from the ejecta of the Great Eruption, rich in HCN and H 13 CN. We also report an absorption component near the continuum point source, only traced by HCN and H 13 CN in their vibrational-ground and vibrationally-excited states. This absorbing gas is attributed to a hot bullet of N-enriched material expelled at a projected velocity of 40 km s −1 .

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Time variations of the narrow Fe II and H I spectral emission lines from the close vicinity of η Carinae during the spectral event of 2003

Cited by 19 publications

References 24 publications

Resonance-enhanced two-photon ionization (RETPI) of Si II and an anomalous, variable intensity of the $\mathsf{\lambda}$1892 Si III] line in the Weigelt blobs of η Carinae

Resonance-enhanced two-photon ionization (RETPI) of Si II and an anomalous, variable intensity of the $\mathsf{\lambda}$1892 Si III] line in the Weigelt blobs of η Carinae

A disrupted molecular torus around Eta Carinae as seen in 12CO with ALMA

The peculiar chemistry of the inner ejecta of Eta Carina

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