True versus apparent shapes of bow shocks

Tarango-Yong, Jorge A.; Henney, W. J.

doi:10.1093/mnras/sty669

Cited by 9 publications

(10 citation statements)

References 47 publications

(64 reference statements)

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Interestingly, this effect is the opposite of what is seen in simulations of MHD bow shocks (Meyer et al 2016), where a parallel B-field leads to flatter-nosed bow shapes with a high planitude (see Fig. 25 of Tarango-Yong & Henney 2018). Figure 14ab shows that the field orientation has a similar effect on the dust wave shape for dragconfined magnetic dust waves, but with the added complication that a second dense shell forms on one side of the axis at the stagnant drift radius, R ‡ , in cases where v ∞ > 60 km s −1 .…”

Section: Predicted Appearance Of Dust Wavesmentioning

confidence: 86%

“…Paper I's equation (11) allows a more exact value for R 0 to be found numerically in intermediate cases. Note that R 0 is the star-apex distance measured along the symmetry axis of the bow (see Tarango-Yong & Henney 2018 for explanation of nomenclature and discussion of bow shapes), and is calculated in the limit that the momentum transfer occurs at a surface. In cases where the shell's finite width is significant, R 0 , should correspond approximately to the astropause (contact discontinuity) in the WBS regime, or a UV optical depth of unity (as measured from the star) in the RBS regime.…”

Section: Recapitulation Of Paper Imentioning

confidence: 99%

“…and Appendix ?? of Tarango-Yong & Henney (2018). In that paper, the dimensionless quantities planitude Π and alatude Λ are introduced as a way of efficiently characterizing bow shapes.…”

Section: Parallel Dust Streammentioning

confidence: 99%

See 2 more Smart Citations

Bow shocks, bow waves, and dust waves – II. Beyond the rip point

Henney

Arthur

2019

Monthly Notices of the Royal Astronomical Society

Self Cite

View full text Add to dashboard Cite

Dust waves are a result of gas-grain decoupling in a stream of dusty plasma that flows past a luminous star. The radiation field is sufficiently strong to overcome the collisional coupling between grains and gas at a rip-point, where the ratio of radiation pressure to gas pressure exceeds a critical value of roughly 1000. When the rip point occurs outside the hydrodynamic bow shock, a separate dust wave may form, decoupled from the gas shell, which can either be drag-confined or inertia-confined, depending on the stream density and relative velocity. In the drag-confined case, there is a minimum stream velocity of roughly 60 km s −1 that allows a steady-state stagnant drift solution for the dust wave apex. For lower relative velocities, the dust dynamics close to the axis exhibit a limit cycle behavior (rip and snap back) between two different radii. Strong coupling of charged grains to the plasma's magnetic field can modify these effects, but for a quasi-parallel field orientation the results are qualitatively similar to the non-magnetic case. For a quasi-perpendicular field, on the other hand, the formation of a decoupled dust wave is strongly suppressed.

show abstract

Section: Predicted Appearance Of Dust Wavesmentioning

confidence: 86%

Section: Recapitulation Of Paper Imentioning

confidence: 99%

See 1 more Smart Citation

Bow shocks, bow waves, and dust waves – II. Beyond the rip point

Henney

Arthur

2019

Monthly Notices of the Royal Astronomical Society

Self Cite

View full text Add to dashboard Cite

show abstract

“…12 as the distance between the apex of the bow shock and the exoplanets center. Bow shocks described by equation (30) are known as wilkinoids (Cox et al 2012;Tarango-Yong & Henney 2018) and assume a plane parallel incident wind. For the case of a colliding wind, they are known as cantoids (Tarango-Yong & Henney 2018).…”

Section: Density Structure and Bow Shockmentioning

confidence: 99%

Inhibition of the electron cyclotron maser instability in the dense magnetosphere of a hot Jupiter

Daley-Yates

Stevens

2018

Monthly Notices of the Royal Astronomical Society

View full text Add to dashboard Cite

Hot Jupiter (HJ) type exoplanets are expected to produce strong radio emission in the MHz range via the electron cyclotron maser instability (ECMI). To date, no repeatable detections have been made. To explain the absence of observational results, we conduct three-dimensional adaptive mess refinement (AMR) magnetohydrodynamic simulations of the magnetic interactions between a solar type star and HJ using the publicly available code PLUTO. The results are used to calculate the efficiency of the ECMI at producing detectable radio emission from the planets magnetosphere. We also calculate the frequency of the ECMI emission, providing an upper and lower bounds, placing it at the limits of detectability due to Earth's ionospheric cutoff of ∼10 MHz. The incident kinetic and magnetic power available to the ECMI is also determined, and a flux of 0.069 mJy for an observer at 10 pc is calculated. The magnetosphere is also characterized and an analysis of the bow shock, which forms upstream of the planet, is conducted. This shock corresponds to the thin shell model for a colliding wind system. A result consistent with a colliding wind system. The simulation results show that the ECMI process is completely inhibited by the planets expanding atmosphere, due to absorption of UV radiation from the host star. The density, velocity, temperature and magnetic field of the planetary wind are found to result in a magnetosphere where the plasma frequency is raised above that due to the ECMI process making the planet undetectable at radio MHz frequencies.

show abstract

“…Gvaramadze et al 2012), as well as on the orientation of the stellar motion relative to the observer's line of sight (LOS) (see e.g. Tarango-Yong & Henney 2018). Because Earth is located inside the heliosphere, numerical models of the latter can be compared to observational data with much higher spatial resolution than for other astrospheres.…”

Section: Introductionmentioning

confidence: 99%

Skymaps of observables of three-dimensional magnetohydrodynamic astrosphere models

Baalmann

Scherer

Fichtner

et al. 2020

A&A

View full text Add to dashboard Cite

Context. Three-dimensional models of astrospheres have recently become of interest. However, comparisons between these models and observations are non-trivial because of the two-dimensional nature of observations. Aims. By projecting selected physical values of three-dimensional models of astrospheres onto the surface of a sphere that is centred on a virtual all-sky observer, these models can be compared to observational data in different observables: the column density, bremsstrahlung flux, rotation measure, Hα flux, and synchrotron or cyclotron flux. Methods. Projections were calculated by rotating and moving the astrosphere model to the desired position and orientation and by then computing the value of a given patch on the sphere by a modified line-of-sight integration. Contributions to the selected observable made by all model cells that are connected to the patch by the line of sight in question were taken into account.Results. When the model produces a bow shock, a distinct parabolic structure produced by the outer astrosheath can be seen in every observable of the projection, the exact shape depending on the orientations of the line of sight and the stellar motion. Of all four examined astrosphere models, only that of λ Cephei shows fluxes that are higher than current observational thresholds. This is due to the strong stellar wind and interstellar inflow of the λ Cephei model.

show abstract

True versus apparent shapes of bow shocks

Cited by 9 publications

References 47 publications

Bow shocks, bow waves, and dust waves – II. Beyond the rip point

Bow shocks, bow waves, and dust waves – II. Beyond the rip point

Inhibition of the electron cyclotron maser instability in the dense magnetosphere of a hot Jupiter

Skymaps of observables of three-dimensional magnetohydrodynamic astrosphere models

Contact Info

Product

Resources

About