Hot Gas in the Circumstellar Bubble S308

Chu, You‐Hua; Guerrero, M. A.; Gruendl, R. A.; Garcı́a-Segura, Guillermo; Wendker, H. J.

doi:10.1086/379607

Cited by 53 publications

(91 citation statements)

References 31 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…We therefore do not draw strong conclusions about turbulent mixing from the results of the simulations presented here. On the other hand, the X-ray morphology that we predict is rather similar to that observed for the more luminous WR bubble S308 (Chu et al 2003), so it is worthwhile to explore the turbulent mixing process with more detailed future simulations. Notes.…”

Section: Mixing At the Contact Discontinuitysupporting

confidence: 70%

Wind bubbles within H ii regions around slowly moving stars

Mackey¹,

Gvaramadze

Mohamed

et al. 2014

A&A

107

View full text Add to dashboard Cite

Interstellar bubbles around O stars are driven by a combination of the star's wind and ionizing radiation output. The wind contribution is uncertain because the boundary between the wind and interstellar medium is difficult to observe. Mid-infrared observations (e.g., of the H ii region RCW 120) show arcs of dust emission around O stars, contained well within the H ii region bubble. These arcs could indicate the edge of an asymmetric stellar wind bubble, distorted by density gradients and/or stellar motion. We present twodimensional, radiation-hydrodynamics simulations investigating the evolution of wind bubbles and H ii regions around massive stars moving through a dense (n H = 3000 cm −3 ), uniform medium with velocities ranging from 4 to 16 km s −1 . The H ii region morphology is strongly affected by stellar motion, as expected, but the wind bubble is also very aspherical from birth, even for the lowest space velocity considered. Wind bubbles do not fill their H ii regions (we find filling factors of 10-20 per cent), at least for a main sequence star with mass M ∼ 30 M . Furthermore, even for supersonic velocities the wind bow shock does not significantly trap the ionization front. X-ray emission from the wind bubble is soft, faint, and comes mainly from the turbulent mixing layer between the wind bubble and the H ii region. The wind bubble radiates <1 per cent of its energy in X-rays; it loses most of its energy by turbulent mixing with cooler photoionized gas. Comparison of the simulations with the H ii region RCW 120 shows that its dynamical age is 0.4 Myr and that stellar motion 4 km s −1 is allowed, implying that the ionizing source is unlikely to be a runaway star but more likely formed in situ. The region's youth, and apparent isolation from other O or B stars, makes it very interesting for studies of massive star formation and of initial mass functions.

show abstract

Section: Mixing At the Contact Discontinuitysupporting

confidence: 70%

Wind bubbles within H ii regions around slowly moving stars

Mackey¹,

Gvaramadze

Mohamed

et al. 2014

A&A

107

View full text Add to dashboard Cite

show abstract

“…The parameter N OVI can be calculated as Notes. (a) Distance, spectral type, and stellar wind velocity taken from van der Hucht (2001), except for the distance of WR 6 that was taken from the kinematic distance estimated by Chu et al (2003). (b) For NGC 6888 this is the semi-major axis.…”

Section: Resultsmentioning

confidence: 99%

Absence of hot gas within the Wolf-Rayet bubble around WR 16

Toalá

Guerrero

2013

A&A

View full text Add to dashboard Cite

We present the analysis of XMM-Newton archival observations towards the Wolf-Rayet (WR) bubble around WR 16. Despite the closed bubble morphology of this WR nebula, the XMM-Newton observations show no evidence of diffuse emission in its interior as in the similar WR bubbles NGC 6888 and S 308. We use the present observations to estimate a 3-σ upper limit to the X-ray luminosity in the 0.3-1.5 keV energy band equal to 7.4 × 10 32 erg s −1 for the diffuse emission from the WR nebula, assuming a distance of 2.37 kpc. The WR nebula around WR 16 is the fourth observed by the current generation of X-ray satellites and the second not detected. We also examine FUSE spectra to search for nebular O vi absorption lines in the stellar continuum of WR 16. The present far-UV data and the lack of measurements of the dynamics of the optical WR bubble do not allow us to confirm the existence of a conductive layer of gas at T ∼ 3 × 10 5 K between the cold nebular gas and the hot gas in its interior. The present observations result in an upper limit of n e < 0.6 cm −3 on the electron density of the X-ray emitting material within the nebula.

show abstract

“…We use the ISIS package [17] to compute the X-ray emission. The vmekal model in XSPEC, commonly used to fit the observed X-ray spectra [5], is used to model the spectrum, although any other available XSPEC model can be substituted. We have also tried the Raymond-Smith model (vraymond), which gave similar results.…”

Section: X-ray Emissionmentioning

confidence: 99%

“…Line broadening is added based on the underlying fluid velocity, and seems to adequately reproduce the broadening in observed spectra. Solar abundances [1] are used for the MS and RSG stages, while abundances in the W-R phase are from [5] for the W-R bubble S308, one of two W-R bubbles to be detected in diffuse X-rays.…”

Section: X-ray Emissionmentioning

confidence: 99%

Simulated X-ray spectra from ionized wind-blown nebulae around massive stars

Dwarkadas¹,

Rosenberg²

2013

High Energy Density Physics

View full text Add to dashboard Cite

Using an ionization gasdynamics code, we simulate a model of the wind-blown bubble around a 40 M ⊙ star. We use this to compute the X-ray spectra from the bubble, which can be directly compared to observations. We outline our methods and techniques for these computations, and contrast them with previous calculations. Our simulated X-ray spectra compare reasonably well with observed spectra of Wolf-Rayet bubbles. They suggest that X-ray nebulae around massive stars may not be easily detectable, consistent with observations.

show abstract

Hot Gas in the Circumstellar Bubble S308

Cited by 53 publications

References 31 publications

Wind bubbles within H ii regions around slowly moving stars

Wind bubbles within H ii regions around slowly moving stars

Absence of hot gas within the Wolf-Rayet bubble around WR 16

Simulated X-ray spectra from ionized wind-blown nebulae around massive stars

Contact Info

Product

Resources

About