Possible implications of mass accretion in Eta Carinae

Kashi, Amit; Soker, Noam

doi:10.1016/j.newast.2008.04.003

Cited by 54 publications

(94 citation statements)

References 49 publications

(105 reference statements)

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“…Even though our simulation does not model the reaction of the secondary and its wind to the accreted mass and its likely feedback on the accreted gas, we measured the amount of mass that reaches the secondary and find it to be in the order of ≈ 10 −6 M⊙ yr −1 , in agreement with the calculations of Kashi & Soker (2009b).…”

Section: Resultssupporting

confidence: 73%

“…As the orbital separation increases, accretion rate decreases (Kashi & Soker 2009b), and the secondary wind is expected to resume.…”

Section: Summary and Discussionmentioning

confidence: 99%

“…Accretion was then ⋆ E-mail: kashi@ariel.ac.il used to model the spectroscopic events (Akashi et al 2006;Kashi & Soker 2009a). Kashi & Soker (2009b) performed a more detailed calculation, integrating over time and volume of the density within the Bondi-Hoyle-Lyttleton accretion radius around the secondary, and found that accretion should take place close to periastron and the secondary should accrete ∼ 2 × 10 −6 M⊙ each cycle. Other papers referred to a "collapse" of the colliding winds region at the spectroscopic event.…”

Section: Introductionmentioning

confidence: 99%

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Accretion at the periastron passage of Eta Carinae

Kashi

2016

Mon. Not. R. Astron. Soc.

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We present high resolution numerical simulations of the colliding wind system η Carinae, showing accretion onto the secondary star close to periastron passage. Our hydrodynamical simulations include self gravity and radiative cooling. The smooth stellar winds collide and develop instabilities, mainly the non-linear thin shell instability, and form filaments and clumps. We find that a few days before periastron passage the dense filaments and clumps flow towards the secondary as a result of its gravitational attraction, and reach the zone where we inject the secondary wind. We run our simulations for the conventional stellar masses, M 1 = 120 M ⊙ and M 2 = 30 M ⊙ , and for a high mass model, M 1 = 170 M ⊙ and M 2 = 80 M ⊙ , that was proposed to better fit the history of giant eruptions. As expected, the simulations results show that the accretion processes is more pronounced for a more massive secondary star.

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Section: Resultssupporting

confidence: 73%

“…As the orbital separation increases, accretion rate decreases (Kashi & Soker 2009b), and the secondary wind is expected to resume.…”

Section: Summary and Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Accretion at the periastron passage of Eta Carinae

Kashi

2016

Mon. Not. R. Astron. Soc.

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“…Soker et al have discussed in a series of papers an accretion model for η Car, which argues for the opposite effect that we just stated (see, e.g., Soker 2005, Kashi & Soker 2008a2009b). In their scenario, the companion accretes mass from η Car during periastron.…”

Section: Possible Scenarios For the Observed Changes In η Carmentioning

confidence: 56%

Near-infrared evidence for a sudden temperature increase in Eta Carinae

Mehner¹,

Ishibashi²,

Whitelock³

et al. 2014

A&A

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Aims. Eta Car's ultra-violet, optical, and X-ray light curves and its spectrum suggest a physical change in its stellar wind over the last decade. It was proposed that the mass-loss rate decreased by a factor of about 2 in the last 15 years. We complement these recent results by investigating the past evolution and the current state of η Car in the near-infrared (IR). Results. The long-term brightening trends in η Car's JHKL light curves were discontinuous around the 1998 periastron passage. After 1998, the star shows excess emission above the extrapolated trend from earlier dates, foremost in J and H, and the blueward, cyclical progression in its near-IR colors is accelerated. The near-IR color evolution is strongly correlated with the periastron passages. After correcting for the secular trend we find that the color evolution matches an apparent increase in blackbody temperature of an optically thick near-IR emitting plasma component from about 3500 to 6000 K over the last 20 years. Conclusions. We suggest that the changing near-IR emission may be caused by variability in optically thick bremsstrahlung emission. Periastron passages play a key role in the observed excess near-IR emission after 1998 and the long-term color evolution. We thus propose as a hypothesis that angular momentum transfer (via tidal acceleration) during periastron passages leads to sudden changes in η Car's atmosphere resulting in a long-term decrease in the mass-loss rate.

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“…Studies of the binary or binary wind-wind collision zone were reported by many authors (e.g., Damineli 1996;Damineli et al 1997Damineli et al , 1998Damineli et al , 2000Damineli et al , 2008bDavidson 1997;Davidson et al 2005Davidson et al , 2015Smith & Gehrz 2000;Smith et al 2004;Smith 2010;Pittard & Corcoran 2002;Corcoran et al 1997Corcoran et al , 2001Corcoran 2005;Ishibashi et al 1999;Soker 2003Soker , 2007Weis et al 2005;Gull et al 2006Gull et al , 2009Gull et al , 2011Gull et al , 2016Nielsen et al 2007;Weigelt et al 2007; Kashi & Soker 2007, 2009aParkin et al 2009;Groh et al 2010Groh et al , 2012bMadura & Owocki 2010;Madura et al 2012Madura et al , 2013Mehner et al 2010aMehner et al , 2011Mehner et al , 2012Mehner et al , 2015Richardson et al 2010;Teodoro et al 2013Teodoro et al , 2016Clementel et al 2015a,b;Hamaguchi et al 2016). The X-ray...…”

Section: Introductionmentioning

confidence: 99%

VLTI-AMBER velocity-resolved aperture-synthesis imaging ofηCarinae with a spectral resolution of 12 000

Weigelt

Hofmann

Schertl

et al. 2016

A&A

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Context. The mass loss from massive stars is not understood well. η Carinae is a unique object for studying the massive stellar wind during the luminous blue variable phase. It is also an eccentric binary with a period of 5.54 yr. The nature of both stars is uncertain, although we know from X-ray studies that there is a wind-wind collision whose properties change with orbital phase. Aims. We want to investigate the structure and kinematics of η Car's primary star wind and wind-wind collision zone with a high spatial resolution of ∼6 mas (∼14 au) and high spectral resolution of R = 12 000. Methods. Observations of η Car were carried out with the ESO Very Large Telescope Interferometer (VLTI) and the AMBER instrument between approximately five and seven months before the August 2014 periastron passage. Velocity-resolved aperture-synthesis images were reconstructed from the spectrally dispersed interferograms. Interferometric studies can provide information on the binary orbit, the primary wind, and the wind collision.Results. We present velocity-resolved aperture-synthesis images reconstructed in more than 100 different spectral channels distributed across the Brγ 2.166 µm emission line. The intensity distribution of the images strongly depends on wavelength. At wavelengths corresponding to radial velocities of approximately −140 to −376 km s −1 measured relative to line center, the intensity distribution has a fan-shaped structure. At the velocity of −277 km s −1 , the position angle of the symmetry axis of the fan is ∼126 • . The fan-shaped structure extends approximately 8.0 mas (∼18.8 au) to the southeast and 5.8 mas (∼13.6 au) to the northwest, measured along the symmetry axis at the 16% intensity contour. The shape of the intensity distributions suggests that the obtained images are the first direct images of the innermost wind-wind collision zone. Therefore, the observations provide velocity-dependent image structures that can be used to test three-dimensional hydrodynamical, radiative transfer models of the massive interacting winds of η Car.

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Possible implications of mass accretion in Eta Carinae

Cited by 54 publications

References 49 publications

Accretion at the periastron passage of Eta Carinae

Accretion at the periastron passage of Eta Carinae

Near-infrared evidence for a sudden temperature increase in Eta Carinae

VLTI-AMBER velocity-resolved aperture-synthesis imaging ofηCarinae with a spectral resolution of 12 000

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