To<i>v</i><sub>∞</sub>and beyond! The He i absorption variability across the 2014.6 periastron passage of η Carinae

Richardson, Noel D.; Madura, Thomas; St-Jean, Lucas; Moffat, A. F. J.; Gull, Theodore R.; Russell, Christopher M. P.; Damineli, A.; Teodoro, Mairan; Corcoran, M. F.; Walter, Frederick M.; Clementel, Nicola; Groh, J. H.; Hamaguchi, Kenji; Hillier, D. J.

doi:10.1093/mnras/stw1415

Cited by 23 publications

(37 citation statements)

References 59 publications

(122 reference statements)

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“…Based on these early suggestions, there have been a few interpretations of observations of spectral lines accross the periastron passage of η Car as being emitted or absorbed by blobs in the winds colliding region, (e.g, Kashi & Soker 2009c;Richardson et al 2016). Our simulations confirmed that the dense clumps are crucial to the onset of the accretion process.…”

Section: Summary and Discussionsupporting

confidence: 65%

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: Summary and Discussionsupporting

confidence: 65%

Accretion at the periastron passage of Eta Carinae

Kashi

2016

Mon. Not. R. Astron. Soc.

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“…Further, the R−band is also contaminated by Hα, which contains emission from the primary's stellar wind and the wind-wind collision zone. Neither the contamination by the Homunculus or by Hα can be easily corrected, but recent spectra by Richardson et al (2016b) show that the Hα contribution is at least 35 − 40% of the observed light in the BRITE red filter near apastron, corresponding approximately to the orbital phase of the BRITE photometry reported here. We show a sample spectrum of the central region of the η Car system along with the BRITE-Constellation response filter in Fig.…”

Section: Discussionmentioning

confidence: 68%

BRITE-Constellation reveals evidence for pulsations in the enigmatic binary η Carinae

Richardson

Pablo

Sterken

et al. 2018

Monthly Notices of the Royal Astronomical Society

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η Car is a massive, eccentric binary with a rich observational history. We obtained the first high-cadence, high-precision light curves with the BRITE-Constellation nanosatellites over 6 months in 2016 and 6 months in 2017. The light curve is contaminated by several sources including the Homunculus nebula and neighboring stars, including the eclipsing binary CPD −59 • 2628. However, we found two coherent oscillations in the light curve. These may represent pulsations that are not yet understood but we postulate that they are related to tidally excited oscillations of η Car's primary star, and would be similar to those detected in lower-mass eccentric binaries. In particular, one frequency was previously detected by van Genderen et al. and Sterken et al. through the time period of 1974 to 1995 through timing measurements of photometric maxima. Thus, this frequency seems to have been detected for nearly four decades, indicating that it has been stable in frequency over this time span. These pulsations could help provide the first direct constraints on the fundamental parameters of the primary star if confirmed and refined with future observations.

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“…HST also enabled imagery into the near ultraviolet (NUV) and spectro-imagery further into the UV down to Ly α. For example, it became clear that the narrow forbidden lines are confined to the Weigelt clumps and other fainter clumpy structures (Davidson et al 1995;Davidson & Humphreys 1997;Smith et al 2002;Hartman 2005;Nielsen et al 2005Nielsen et al , 2007Gull et al 2009;Mehner et al 2010;Richardson et al 2016;Zethson et al 2012;Gull et al 2016). Multiple, spatially-resolved complex spectral structures were noted both in the central source (Hillier et al 2006) and nearby structures including the Weigelt clumps and the fossil winds (Gull et al 2009(Gull et al , 2016.…”

Section: Introductionmentioning

confidence: 99%

Distinguishing circumstellar from stellar photometric variability in Eta Carinae

Damineli¹,

Lajús

Almeida

et al. 2019

Monthly Notices of the Royal Astronomical Society

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The interacting binary Eta Carinae remains one of the most enigmatic massive stars in our Galaxy despite over four centuries of observations. In this work, its light curve from the ultraviolet to the near-infrared is analysed using spatially resolved HST observations and intense monitoring at the La Plata Observatory, combined with previously published photometry. We have developed a method to separate the central stellar object in the ground-based images using HST photometry and applying it to the more numerous ground-based data, which supports the hypothesis that the central source is brightening faster than the almost-constant Homunculus. After detrending from longterm brightening, the light curve shows periodic orbital modulation (∆V ∼ 0.6 mag) attributed to the wind-wind collision cavity as it sweeps around the primary star and it shows variable projected area to our line-of-sight. Two quasi-periodic components with time scales of 2-3 and 8-10 yr and low amplitude, ∆V < 0.2 mag, are superimposed on the brightening light-curve, being the only stellar component of variability found, which indicates minimal stellar instability. Moreover, the light curve analysis shows no evidence of "shell ejections" at periastron. We propose that the long-term brightening of the stellar core is due to the dissipation of a dusty clump in front of the central star, which works like a natural coronagraph. Thus, the central stars appear to be more stable than previously thought since the dominant variability originates from a changing circumstellar medium. We predict that the brightening phase, due mainly to dust dissipation, will be completed around 2032 ± 4 yr, when the star will be brighter than in the 1600's by up to ∆V ∼ 1 mag.

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Tov_∞and beyond! The He i absorption variability across the 2014.6 periastron passage of η Carinae

Cited by 23 publications

References 59 publications

Accretion at the periastron passage of Eta Carinae

Accretion at the periastron passage of Eta Carinae

BRITE-Constellation reveals evidence for pulsations in the enigmatic binary η Carinae

Distinguishing circumstellar from stellar photometric variability in Eta Carinae

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Tov∞and beyond! The He i absorption variability across the 2014.6 periastron passage of η Carinae

Cited by 23 publications

References 59 publications

Accretion at the periastron passage of Eta Carinae

Accretion at the periastron passage of Eta Carinae

BRITE-Constellation reveals evidence for pulsations in the enigmatic binary η Carinae

Distinguishing circumstellar from stellar photometric variability in Eta Carinae

Contact Info

Product

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Tov_∞and beyond! The He i absorption variability across the 2014.6 periastron passage of η Carinae