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Temporal variations in the evaporating atmosphere of the exoplanet HD 189733b
Atmospheric escape has been detected from the exoplanet HD 209458b through transit observations of the hydrogen Lyman-α line. Here we present spectrally resolved Lyman-α transit observations of theExpand
A giant comet-like cloud of hydrogen escaping the warm Neptune-mass exoplanet GJ 436b
In the ultraviolet the Neptune-mass exoplanet GJ 436b (also known as Gliese 436b) has transit depths of 56.3 ± 3.5% (1σ), far beyond the 0.69% optical transit depth, and it is inferred that the planet is surrounded and trailed by a large exospheric cloud composed mainly of hydrogen atoms. Expand
An ultrahot gas-giant exoplanet with a stratosphere
A near-infrared thermal spectrum for the ultrahot gas giant WASP-121b, which has an equilibrium temperature of approximately 2,500 kelvin, is reported, implying that a substantial fraction of incident stellar radiation is retained at high altitudes in the atmosphere, possibly by absorbing chemical species such as gaseous vanadium oxide and titanium oxide. Expand
Strong XUV irradiation of the Earth-sized exoplanets orbiting the ultracool dwarf TRAPPIST-1
We present an XMM-Newton X-ray observation of TRAPPIST-1, which is an ultracool dwarf star recently discovered to host three transiting and temperate Earth-sized planets. We find the star is aExpand
Atmospheric escape from HD 189733b observed in H I Lyman-α: detailed analysis of HST/STIS September 2011 observations
Observations of transits of the hot giant exoplanet HD189733b in the unresolved Hi Lyman-� line show signs of hydrogen escaping the upper atmosphere of the planet. New resolved Lyman-� observationsExpand
An evaporating planet in the wind: stellar wind interactions with the radiatively braked exosphere of GJ 436 b
Observations of the warm Neptune GJ 436 b were performed with HST/STIS at three different epochs (2012, 2013, 2014) in the stellar Lyman- α line. They showed deep, repeated transits that wereExpand
Helium in the eroding atmosphere of an exoplanet
A detection of helium absorption at 10,833 Å on the exoplanet WASP-107b reveals that its atmosphere is extended and eroding, and demonstrates a new way to study upper exoplanetary atmospheres. Expand
The 55 Cancri system reassessed
Orbiting a bright, nearby star the 55 Cnc system offers a rare opportunity to study a multiplanet system that has a wide range of planetary masses and orbital distances. Using two decades ofExpand
Spectrally resolved helium absorption from the extended atmosphere of a warm Neptune-mass exoplanet
The detection of the near-infrared triplet of neutral helium in the transiting warm Neptune-mass exoplanet HAT-P-11b by using ground-based, high-resolution observations and interpreting absorption spectra with three-dimensional simulations of the planet’s upper atmosphere suggests that it extends beyond 5 planetary radii. Expand
Hint of a transiting extended atmosphere on 55 Cancri b
The naked-eye star 55 Cancri hosts a planetary system with five known planets, including a hot super-Earth (55 Cnc e) extremely close to its star and a farther out giant planet (55 Cnc b), found inExpand