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

Autor(en): K. G Kislyakova, Elke Pilat-Lohinger, Barbara Funk, Helmut Lammer, Luca Fossati, Richard Schwarz
Abstrakt: 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 L₄ and L₅. 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 WASP-12b, 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 · 10²⁷ s^-1 and ≈2.2 · 10²⁶ s^-1, respectively. Trojan outgassing can lead to the apparent lack of emission in Mg II h&k and Ca II 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 could not explain the early ingress of HD 189733b observed in the far-UV C II 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 lifetime.
Organisation(en): Institut für Astrophysik
Externe Organisation(en): Österreichische Akademie der Wissenschaften (ÖAW)
Journal: Monthly Notices of the Royal Astronomical Society
Band: 461
Seiten: 988 - 999
Anzahl der Seiten: 12
ISSN: 0035-8711
DOI: https://doi.org/10.1093/mnras/stw1110
Publikationsdatum: 09-2016
Peer-reviewed: Ja
ÖFOS 2012: 103003 Astronomie, 103004 Astrophysik
Schlagwörter
ASJC Scopus Sachgebiete: Astronomy and Astrophysics, Space and Planetary Science
Link zum Portal: https://ucrisportal.univie.ac.at/de/publications/f223ef1c-c400-466b-9ce6-2f5c8344cd65

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