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

Abstract

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.

How expanded ionospheres of Hot Jupiters can prevent escape of radio emission generated by the cyclotron maser instability

“…Also for Earth, the gyrofrequency lies above the plasma frequency from about 1 planetary radius up to 6 Earth radii (see Figure 13 in Gurnett 1974). However, for Hot Jupiters an Io-like plasma source is probably impossible, because they likely can have none or at least only tiny moons (e.g., Kislyakova et al (2016) and refer-ences therein). On the other hand, Kislyakova et al (2016) have shown that for the hottest planets, a Trojan swarm orbiting in 1:1 resonance with the giant planet could provide a plasma source, but further investigation of CMI conditions in these systems is needed.…”

The TROY project: Searching for co-orbital bodies to known planets

“…Other previously analyzed system in the context of trojan planets is WASP-12. In a recent paper by Kislyakova et al (2016), the authors have sought to explain some intriguing features in the ultraviolet light curve of the hot Jupiter in this system by assuming the presence of Io-like trojans. In particular, in the case of WASP-12, an early ingress in the ultraviolet transit of the planet was found as compared to the optical transit times; the egress time agrees in all wavelengths analyzed.…”

Investigating the physical properties of transiting hot Jupiters with the 1.5-m Kuiper Telescope

“…Additionally, theoretical modeling by Turner et al (2016a) using the CLOUDY plasma simulation code showed that asymmetric transits cannot be produced in the broadband near-UV band regardless of the assumed physical phe-nomena that could cause absorption (e.g. Vidotto et al 2010;Lai et al 2010;Ben-Jaffel & Ballester 2014;Matsakos et al 2015;Kislyakova et al 2016).…”