The maximum size of a stationary, quasi-closed gaseous envelope around the hot jupiter WASP-12b

Bisikalo, D. V.; Kaigorodov, P. V.; Konstantinova, N. I.

doi:10.1134/s1063772915090012

Cited by 30 publications

(6 citation statements)

References 17 publications

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“…This suggests that transit light-curves obtained from broad-band UV observations alone cannot provide strong limits on these parameters. Wider phase coverage in particular is necessary if we are to break these degeneracies and establish a unique solution (see also Bisikalo et al 2015). then this "excess" flux in the post-transit region will be negligible (see discussion in Section 6.2).…”

Section: Light-curvesmentioning

confidence: 99%

Magnetospheres of hot Jupiters: hydrodynamic models and ultraviolet absorption

Alexander¹,

Wynn²,

Mohammed³

et al. 2015

Mon. Not. R. Astron. Soc.

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We present hydrodynamic simulations of stellar wind-magnetosphere interactions in hot Jupiters such as WASP-12b. For fiducial stellar wind rates we find that a planetary magnetic field of a few G produces a large magnetospheric cavity, which is typically 6-9 planetary radii in size. A bow shock invariably forms ahead of the magnetosphere, but the pre-shock gas is only mildly supersonic (with typical Mach numbers of ≃ 1.6-1.8) so the shock is weak. This results in a characteristic signature in the ultraviolet light curve: a broad absorption feature that leads the optical transit by 10-20% in orbital phase. The shapes of our synthetic lightcurves are consistent with existing observations of WASP-12b, but the required near-UV optical depth (τ ∼ 0.1) can only be achieved if the shocked gas cools rapidly. We further show that radiative cooling is inefficient, so we deem it unlikely that a magnetospheric bow shock is responsible for the observed near-UV absorption. Finally, we apply our model to two other well-studied hot Jupiters (WASP-18b and HD209458b), and suggest that UV observations of more massive short-period planets (such as WASP-18b) will provide a straightforward test to distinguish between different models of circumplanetary absorption.

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Section: Light-curvesmentioning

confidence: 99%

Magnetospheres of hot Jupiters: hydrodynamic models and ultraviolet absorption

Alexander¹,

Wynn²,

Mohammed³

et al. 2015

Mon. Not. R. Astron. Soc.

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“…This leads to under certain condition the formation of a bow-shock ahead of the planet which opacity may be sufficient to cause the early ingress (Vidotto et al 2010(Vidotto et al , 2011Llama et al 2011). Three-dimensional (3D) simulations of the planetary atmosphere and of its interaction with the stellar wind indicate the formation of a large, asymmetric gaseous envelope around the planet that is likely to reach high enough densities to produce an early ingress (Bisikalo et al 2013(Bisikalo et al , 2015. These 3D simulations are however not self-consistent and do not realistically consider the stellar irradiation, as well as some other non-adiabatic heating and cooling processes on-going in the planetary upper atmosphere, remaining therefore strongly dependent on the prescribed inner boundary conditions, close to the planet.…”

Section: Introductionmentioning

confidence: 99%

Modelling atmospheric escape and Mg ii near-ultraviolet absorption of the highly irradiated hot Jupiter WASP-12b

Dwivedi

Khodachenko

Шайхисламов

et al. 2019

Monthly Notices of the Royal Astronomical Society

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We present two-dimensional multi-fluid numerical modelling of the upper atmosphere of the hot Jupiter WASP-12b. The model includes hydrogen chemistry, and self-consistently describes the expansion of the planetary upper atmosphere and mass loss due to intensive stellar irradiation, assuming a weakly magnetized planet. We simulate the planetary upper atmosphere and its interaction with the stellar wind (SW) with and without the inclusion of tidal force and consider different XUV irradiation conditions and SW parameters. With the inclusion of tidal force, even for a fast SW, the escaping planetary material forms two streams, propagating towards and away from the star. The atmospheric escape and related mass loss rate reaching the value of 10 12 gs -1 appear to be mostly controlled by the stellar gravitational pull. We computed the column density and dynamics of MgII ions considering three different sets of SW parameters and XUV fluxes. The simulations enable to compute the absorption at the position of the Mg h line and to reproduce the times of ingress and egress. In case of a slow SW and without accounting for tidal force, the high orbital velocity leads to the formation of a shock approximately in the direction of the planetary orbital motion. In this case, mass loss is proportional to the stellar XUV flux. At the same time, ignoring of tidal effects for WASP-12b is a strong simplification, so the scenario with a shock, altogether is an unrealistic one.Keywords: planets and satellites: individual: exoplanetplanets and satellites: gaseous planetsplanets and satellites: atmosphereplanets and satellites: dynamical evolution and stabilityplanets and satellites: atmosphereplanet-star interactions

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“…However, this dynamical estimate does not account for an extreme expansion of the atmosphere of WASP-12b. According to hydrodynamic simulations, this hot Jupiters experiences strong Roche lobe overflow (Bisikalo et al 2013(Bisikalo et al , 2015, i.e., it fills its whole Roche lobe with material escaping from the upper layers of its atmosphere. Under these conditions, it is difficult to expect the presence of an exomoon: the only possible stabe orbits lie inside an area filled with planetary escaping particles.…”

Section: Exomoons As An Outgassing Source: Hill Radii and Roche Limitmentioning

confidence: 99%

“…For WASP-12b, the Hill limit extends only until approximately 2Rp. Since it is known that this hot Jupiter is very inflated and experiences Roche lobe overflow (Fossati et al 2010;Haswell et al 2012;Bisikalo et al 2015), it seems very unlikely that this planet can possess a stable satellite even on a retrograde orbit. However, HD 189733b could posses a retrograde moon with a size of approximately 500 km.…”

Section: Exomoons As An Outgassing Source: Hill Radii and Roche Limit...mentioning

confidence: 99%

“…Several explanations have been proposed for these observations. For early ingress, the proposed hypothesis included absorption in the bow shock ahead of the planet with the stand-off distance determined by the planetary magnetic moment (Vidotto et al 2010), and evaporation of atmospheric material from the planet (Fossati et al 2010;Haswell et al 2012;Bisikalo et al 2013Bisikalo et al , 2015. The apparent lack of emission in Mgii h&k and Caii H&K line cores of WASP-12 was originally explained by the presence of absorbing material evaporated from the planet (Haswell et al 2012;Fossati et al 2013).…”

Section: Introductionmentioning

confidence: 99%

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On the ultraviolet anomalies of the WASP-12 and HD 189733 systems: Trojan satellites as a plasma source

Kislyakova

Pilat-Lohinger

Funk

et al. 2016

Mon. Not. R. Astron. Soc.

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We suggest an additional possible plasma source to explain part of the phenomena observed for the transiting hot Jupiters WASP-12b and HD 189733b in their ultraviolet (UV) light curves. In the proposed scenario, material outgasses from the molten surface of Trojan satellites on tadpole orbits near the Lagrange points L 4 and L 5 . We show that the temperature at the orbital location of WASP-12b is high enough to melt the surface of rocky bodies and to form shallow lava oceans on them. In case of WASP12b, this leads to the release of elements such as Mg and Ca, which are expected to surround the system. The predicted Mg and Ca outgassing rates from two Io-sized WASP-12b Trojans are ≈ 2.2 × 10 27 s −1 and ≈ 2.2 × 10 26 s −1 , respectively. Trojan outgassing can lead to the apparent lack of emission in Mgii h&k and Caii H&K line cores of WASP-12. For HD 189733b, the mechanism is only marginally possible due to the lower temperature. This may be one of the reasons that couldn't explain the early ingress of HD 189733b observed in the far-UV (FUV) Cii doublet due to absence of carbon within elements outgassed by molten lava. We investigate the long-term stability region of WASP-12b and HD 189733b in case of planar and inclined motion of these satellites and show that unlike the classical exomoons orbiting the planet, Io-sized Trojans can be stable for the whole systems life time.

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The maximum size of a stationary, quasi-closed gaseous envelope around the hot jupiter WASP-12b

Cited by 30 publications

References 17 publications

Magnetospheres of hot Jupiters: hydrodynamic models and ultraviolet absorption

Magnetospheres of hot Jupiters: hydrodynamic models and ultraviolet absorption

Modelling atmospheric escape and Mg ii near-ultraviolet absorption of the highly irradiated hot Jupiter WASP-12b

On the ultraviolet anomalies of the WASP-12 and HD 189733 systems: Trojan satellites as a plasma source

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