Hubble Space Telescope detection of oxygen in the atmosphere of exoplanet HD 189733b

摘要: Detecting heavy atoms in the inflated atmospheres of giant exoplanets that orbit close to their parent stars is a key factor for understanding bulk composition, evolution, and processes drive expansion interaction with impinging stellar wind. Unfortunately, very few detections have been made thus far. Here, we use archive data obtained Cosmic Origins Spectrograph onboard Hubble Space Telescope report an absorption ∼6.4%±1.8% by neutral oxygen during HD 189733b transit. Using published results from simple hydrodynamic model 189733b, assuming mean temperature ∼(8−12) × 10 3 Kf or upper atmosphere exoplanet, vertical integrated O I density column ∼8 15 cm −2 produces only 3.5% attenuation Much like case hot-Jupiter 209458b, super-solar abundances and/or super-thermal broadening lines are required fit deep transit drop-off observed most far-ultraviolet lines. We also evidence short-time variability measured flux, analyze using time series derived time-tagged exposures, which then compare solar flaring activity. In frame, find non-statistical uncertainties fluxes not negligible, calls caution when reporting absorptions. Despite cumulative originate sky background signals instrument response, show possible detection both early-ingress ion C II 133.5 nm If confirmed, this would be second exoplanet early ingress reported. contrast, such signature detected I. Assuming magnetosphere at origin absorption, Parker wind particle-in-cell code its orientation should deflected ∼10−30 ◦ planet-star line, while nose’s position least ∼16.7 Rp upstream order light curve. The stand-off distance consistent surface magnetic field strength ∼5.3 Gauss supersonic ∼250 km s −1 , 1.2 5 K ∼6.3 6 −3 planetary orbit, yet unique.