Self-similar solutions for the interaction regions of colliding winds

Chevalier, Roger A.; Imamura, James N.

doi:10.1086/161147

Cited by 50 publications

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“…Our 1-D spherical models are in good agreement with analytical solutions of the structure and kinematics of the hot bubble (Chevalier & Imamura 1983 resulting from the wind-wind interaction. These models also support many of the analytical results of ASB06, although interesting differences occur.…”

Section: Simulations and Resultssupporting

confidence: 73%

“…The atomic database ATOMDB with IDL (Smith et al 2001) is used to calculate the emissivity. We compute the total flux in X-rays, the spectrum and emission maps.Our 1-D spherical models are in good agreement with analytical solutions of the structure and kinematics of the hot bubble (Chevalier & Imamura 1983 resulting from the wind-wind interaction. These models also support many of the analytical results of ASB06, although interesting differences occur.…”

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confidence: 73%

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Investigating X-ray Emission from PPN and PN using numerical simulations

Stute¹,

Sahai²

2006

IAU

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Abstract. The shaping of Pre-planetary nebulae (PPN) and Planetary Nebulae (PN) is believed to result from the interaction of a fast, collimated post-AGB wind (CFW) plowing into the slow, dense wind emitted during the AGB phase, followed by an isotropic tenuous wind during the PN phase (Sahai & Trauger 1998). The expanding shell which forms the PPN and later the PN is expected to produce extended X-ray emission due to the large speed of the fast wind and resulting high temperatures in the shocked gas. X-ray emission was only detected in 3 of 60 PNs observed with ROSAT, followed by a few more from CHANDRA and XMM (e.g. Guerrero et al. 2005). In the case of PPNs, there is so far only one confirmed X-ray detection (Sahai et al. 2003), although many have been observed with CHANDRA. The general problem of understanding the formation and shaping of PNs has been addressed analytically and numerically (see Balick & Frank 2002, and references therein). X-ray emission is one of the most direct probes of the fast wind and the interaction process which drives PN formation. However, this probe has not been fully exploited in previous modeling studies. Very recently, Akashi et al. (2006, hereafter ASB06) used analytical, self-similar, spherically symmetric models to address this problem. We are performing numerical simulations with the hydrodynamics code FLASH varying the basic parameters of the fast and slow wind over an extensive parameter grid and computing the X-ray emission as a function of these parameters and the time history of the fast wind.Keywords. planetary nebulae: general, X-rays: stars, ISM: jets and outflows, stars: mass loss, hydrodynamics Simulations & ResultsUsing Flash, we solve the differential equations of ideal hydrodynamics, and include radiative losses using the cooling functions of Sutherland & Dopita (1993) and Dalgarno & McCray (1972). We let a fast post-AGB wind (mass loss rateṀ f , velocity v f ) expand into a spherically symmetric, slowly expanding AGB wind (Ṁ s , v s ). The values of these four parameters cover the range adopted from ASB06 for ease of comparison; we have expanded the range to fit models to observations. The expected X-ray flux is determined using the radial density and temperature profiles from the hydrodynamical simulations. The atomic database ATOMDB with IDL (Smith et al. 2001) is used to calculate the emissivity. We compute the total flux in X-rays, the spectrum and emission maps.Our 1-D spherical models are in good agreement with analytical solutions of the structure and kinematics of the hot bubble (Chevalier & Imamura 1983 resulting from the wind-wind interaction. These models also support many of the analytical results of ASB06, although interesting differences occur. For example, we find that the initial phase of low X-ray luminosity, relevant for the understanding of X-rays from PPNe, is significantly shorter than in ASB06. We believe that our results are more accurate because of the self-consistent treatment of radiative cooling and hydrodynamics in our models. 519h...

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Section: Simulations and Resultssupporting

confidence: 73%

supporting

confidence: 73%

Investigating X-ray Emission from PPN and PN using numerical simulations

Stute¹,

Sahai²

2006

IAU

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“…Assuming a spherically symmetric power‐law density distribution, ρ= Kr α , in the ambient circumstellar material, the solution at late times (i.e. when the swept‐up mass is much greater than wind mass) can be written as which for α=−2 gives a constant velocity expansion, as expected from the self‐similar solutions of Chevalier & Imamura (1983). The semimajor axis of each OR can be reasonably well fitted by a ∝ L 1/3 w as shown in Fig.…”

Section: Parameter Studymentioning

confidence: 99%

A binary merger model for the formation of the Supernova 1987A triple-ring nebula

Morris

Podsiadlowski

2009

Monthly Notices of the Royal Astronomical Society

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We examine a binary merger model for the formation of the mysterious triple‐ring nebula surrounding Supernova 1987A, which still has not been convincingly explained in detailed hydrodynamical calculations. During the merger of 15 and 5 M⊙ binary systems, mass is ejected primarily at mid‐latitudes for a sufficiently evolved primary, as demonstrated by Morris & Podsiadlowski. This material is swept up by the fast wind of the central star during its post‐merger blue supergiant phase, leading to a density contrast of ∼150 in the outer rings at the time of the supernova. The equatorial ring probably formed later when the star contracted to become a blue supergiant. The asymmetry between the northern and southern outer rings can be explained by a 10 per cent asymmetry during the merger, perhaps due to a pulsational instability in the common envelope. We present a parameter study from which we determine a mass‐loss rate in the blue supergiant wind in the range 1.5–3 × 10−7 M⊙ yr−1 in agreement with previous estimates. The morphology of the best model is consistent with the well‐known Hubble Space Telescope image at better than 5 per cent and is also in broad agreement with light‐echo observations. The circumstellar environment on larger scales (up to 3 pc) is also investigated. We conclude with a brief discussion of the bipolar nebulae surrounding the Galactic stars, Sheridan 25, HD 168625 and η Carinae.

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“…Also, circumstellar shells could be smaller if their expansion were slower. The velocity V s of an energy, wind-driven shell expanding in a previous wind is given for example by (Chevalier & Imamura 1983):…”

Section: Comparison With Hydrodynamical Models Qsf Locations and Shomentioning

confidence: 99%

Supernova progenitor stars in the initial range of 23 to 33 solar masses and their relation with the SNR Cassiopeia A

Pérez-Rendón

Garcı́a-Segura

Langer

2009

A&A

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Context. Multi wavelength observations of Cassiopeia A (Cas A) have provided us with strong evidence of circumstellar material surrounding the progenitor star. It has been suggested that its progenitor was a massive star with strong mass loss. But, despite the large amount of observational data from optical, IR, radio, and x-ray observations, the identity of Cas A progenitor is still elusive. Aims. In this work, we computed stellar and circumstellar numerical models to look for the progenitor of Cas A. The models are compared with the observational constraints that come from chemical observed abundances and dynamical information. Methods. We first computed stellar evolution models to get time-dependent wind parameters and surface abundances using the code STERN. To explore the range of masses proposed by several previous works, we chose a set of probable progenitor stars with initial masses of 23, 28, 29, 30, and 33 M , with initial solar composition (Y = 0.28, Z = 0.02) and mass loss. The derived mass loss rates and wind terminal velocities are used as inner boundary conditions in the explicit, hydrodynamical code ZEUS-3D to simulate the evolution of the circumstellar medium. We simplified the calculations by using one-dimensional grids in the main sequence and red super-giant (RSG) stages, and two-dimensional grids for the post-RSG evolution and supernova (SN) blast wave. Results. Our stellar set gives distinct SN progenitors: RSG, luminous blue super giants (LBSGs), and Wolf-Rayet (WR) stars. We named these type of stars "luminous blue super giant" (LBSGs) to distinguish them from normal blue super giants (BSGs) of much lower initial masses. The 23 M star explodes as an RSG in a ρ ∼ r −2 dense, free-streaming wind surrounded by a thin, compressed, RSG shell. The 28 M star explodes as an LBSG, and the SN blast wave interacts with a low density, free streaming wind surrounded by an unstable and massive "RSG+LBSG" shell. Finally, the 30 and 33 M stars explode as WR stars surrounded by fast WR winds that terminate in a highly fragmented "WR+RSG shell". We compared the surface chemical abundances of our stellar models with the observational abundances in Cas A. The abundance analysis shows that the progenitor was a star with an initial mass of about 30 M , while the hydrodynamical analysis favors progenitors with initial masses around 23.

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Self-similar solutions for the interaction regions of colliding winds

Cited by 50 publications

References 0 publications

Investigating X-ray Emission from PPN and PN using numerical simulations

Investigating X-ray Emission from PPN and PN using numerical simulations

A binary merger model for the formation of the Supernova 1987A triple-ring nebula

Supernova progenitor stars in the initial range of 23 to 33 solar masses and their relation with the SNR Cassiopeia A

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