Radio evidence of recent mass ejection from   Carinae

Duncan, R. A.; White, S. M.

doi:10.1046/j.1365-8711.2003.06287.x

Cited by 86 publications

(135 citation statements)

References 13 publications

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“…The currently observed orbital period is 5.5 yr, which for primary and companion masses of M 1 ¼ 120 M and M 2 ¼ 30 M , respectively, implies an average orbital separation of a $ 16:5 AU (for observational support for the presence of a binary and its properties see, e.g., Damineli 1996;Ishibashi et al 1999;Damineli et al 2000;Corcoran et al 2001aCorcoran et al , 2001bPittard & Corcoran 2002;Duncan & White 2003;Fernandez Lajus et al 2004). Therefore, the orbital energy of the currently observed binary system cannot account for the kinetic energy of the Homunculus.…”

Section: Wind Energy and Momentummentioning

confidence: 95%

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: Wind Energy and Momentummentioning

confidence: 95%

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

Soker

2004

ApJ

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“…The parameters of the model are listed in Table 1. The magnetic field and the electron energy distribution were adjusted to match the upper limit of the radio synchrotron emission, derived from the minimal thermal emission detected with ACTA (Duncan & White 2003), and match the inverse Compton continuum determined by INTEGRAL and Fermi. The slope and cutoff energy of the interacting proton energy distribution were fixed to 2.25 and 10 4 , respectively, and its normalisation was fitted to match the high-energy gamma-ray tail using the π 0 -decay model of Kelner et al (2006).…”

Section: Electron Bremsstrahlung In the Post-shock Region For A Densitymentioning

confidence: 99%

ηCarinae: a very large hadron collider

Farnier

Walter

Leyder

2010

A&A

109

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Context. η Carinae is the colliding wind binary with the highest mass-loss rate in our Galaxy and the only one in which hard X-ray emission has been detected. Aims. η Carinae is therefore a primary candidate to search for particle acceleration by probing its gamma-ray emission. Methods. We used the first 21 months of Fermi/LAT data to extract gamma-ray (0.2-100 GeV) images, spectra, and light-curves, then combined them with multi-wavelength observations to model the non-thermal spectral energy distribution. Results. A bright gamma-ray source is detected at the position of η Carinae. Its flux at a few 100 MeV can be modelled by an extrapolation of the hard X-ray spectrum towards higher energies. The spectral energy distribution features two distinct components. The first one extends from the keV to GeV energy range, and features an exponential cutoff at ∼1 GeV. It can be understood as inverse Compton scattering of ultraviolet photons by electrons accelerated up to γ ∼ 10 4 in the colliding wind region. The expected synchrotron emission is compatible with the existing upper limit to the non-thermal radio emission. The second component is a hard gamma-ray tail detected above 20 GeV. It could be explained by π 0 -decay of accelerated hadrons interacting with the dense stellar wind. The ratio of the fluxes of the π 0 to inverse Compton components is roughly as predicted by simulations of colliding wind binaries. This hard gamma-ray tail can only be understood if emitted close to the wind collision region. The energy transferred to the accelerated particles (∼5% of the collision mechanical energy) is comparable to that of the thermal X-ray emission. Conclusions. The electron spectrum responsible for the keV to GeV emission was modelled and the observed emission above 20 GeV strongly suggests hadronic acceleration in η Carinae. These observations are thus in good agreement with the colliding wind scenario proposed for η Carinae.

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“…We will further assume that the flux of UV radiation that maintains the disk ionized, suddenly decreases, or maybe even stops, as proposed by Duncan & White (2003).…”

Section: Model For the Mm-wave Emissionmentioning

confidence: 99%

“…Interferometric monitoring with the Australian Telescope Compact Array at 3 and 6 cm with 1 resolution, showed an elongated structure, reaching a maximum size of about 4 (1.3 × 10 17 cm at a distance of 2.3 kpc), which shrinks to less than 1 during the minimum in the light curve (Duncan et al 1997). This effect was interpreted by Duncan & White (2003) as due to a decrease in the number of ionizing photons during the low excitation phase.…”

Section: Introductionmentioning

confidence: 99%

Millimeter-wave emission during the 2003 low excitation phase ofηCarinae

Abraham

Falceta‐Gonçalves

Dominici

et al. 2005

A&A

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Abstract. In this paper we present observations of η Carinae in the 1.3 mm and 7 mm radio continuum, during the 2003.5 low excitation phase. The expected minimum in the light curves was confirmed at both wavelengths and was probably due to a decrease in the number of UV photons available to ionize the gas surrounding the binary system. At 7 mm a very well defined peak was superimposed on the declining flux density. It presented maximum amplitude in 29 June 2003 and lasted for about 10 days. We show that its origin can be free-free emission from the gas at the shock formed by wind-wind collision, which is also responsible for the observed X-ray emission. Even though the shock strength is strongly enhanced as the two stars in the binary system approach each other, during periastron passage the X-ray emission is strongly absorbed and the 7 mm observations represent the only direct evidence of this event.

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Radio evidence of recent mass ejection from Carinae

Cited by 86 publications

References 13 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

ηCarinae: a very large hadron collider

Millimeter-wave emission during the 2003 low excitation phase ofηCarinae

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