相关论文: The space weather around the exoplanet GJ 436b
The late-type dwarf GJ 436 is known to host a transiting Neptune-mass planet in a 2.6-day orbit. We present results of our interferometric measurements to directly determine the stellar diameter ($R_{\star} = 0.455 \pm 0.018 R_{\odot}$) and…
Interactions between stellar and planetary magnetic fields are expected to produce observable radio and optical signals modulated by their orbital periods, but direct detections remain elusive. We analyze 17 years of spectroscopic data of…
The M dwarf star GJ 436 hosts a warm-Neptune that is losing substantial amount of atmosphere, which is then shaped by the interactions with the wind of the host star. The stellar wind is formed by particles and magnetic fields that shape…
We determine stellar parameters for the M dwarf GJ 436 that hosts a Neptune-mass planet. We employ primarily spectral modeling at low and high resolution, examining the agreement between model and observed optical spectra of five comparison…
The GJ 436 planetary system is an extraordinary system. The Neptune-size planet that orbits the M3 dwarf revealed in the Ly$\alpha$ line an extended neutral hydrogen atmosphere. This material fills a comet-like tail that obscures the…
Knowledge of the stellar parameters for the parent stars of transiting exoplanets is pre-requisite for establishing the planet properties themselves, and often relies on stellar evolution models. GJ 436, which is orbited by a transiting…
We report precise Doppler measurements of GJ 436 (M2.5V) obtained at Keck Observatory. The velocities reveal a planetary companion with orbital period of 2.644 d, eccentricity of 0.12 (consistent with zero) and velocity semi-amplitude of $K…
The GJ 436 system contains a transiting planet GJ 436 b which is a hot analogue of Neptune on an eccentric orbit. Recently, two additional transiting sub-Earth planets have been postulated in the literature. We observed three transits of GJ…
We explore the transmission spectrum of the Neptune-class exoplanet GJ 436b, including the possibility that its atmospheric opacity is dominated by a variety of non- equilibrium chemical products. We also validate our transmission code by…
The angle between the spin of a star and its planets' orbital planes traces the history of the planetary system. Exoplanets orbiting close to cool stars are expected to be on circular, aligned orbits because of strong tidal interactions…
The recent detection of a giant exosphere surrounding the warm Neptune GJ436 b has shed new light on the evaporation of close-in planets, revealing that moderately irradiated, low-mass exoplanets could make exceptional targets for studying…
The nearby extrasolar planet GJ 436b--which has been labelled as a 'hot Neptune'--reveals itself by the dimming of light as it crosses in front of and behind its parent star as seen from Earth. Respectively known as the primary transit and…
The Neptune-mass GJ 436b is one of the most-studied transiting exoplanets with repeated measurements of both its thermal emission and transmission spectra. We build on previous studies to answer outstanding questions about this planet,…
Exoplanets orbiting close to their parent stars could lose some fraction of their atmospheres because of the extreme irradiation. Atmospheric mass loss primarily affects low-mass exoplanets, leading to suggest that hot rocky planets might…
The warm Neptune GJ436b was observed with HST/STIS at three different epochs in the stellar Ly-alpha line, showing deep, repeated transits caused by a giant exosphere of neutral hydrogen. The low radiation pressure from the M-dwarf host…
Hot Neptunes in the sub-Jovian desert offer unique insights into planetary system evolution, retaining signatures of dynamical processes that shaped their present-day architectures. Many of these planets exhibit polar orbits, yet the…
The M dwarf GJ 436 hosts a transiting warm Neptune known to experience atmospheric escape. Previous observations revealed the presence of a giant hydrogen exosphere transiting the star for more than 5 h, and absorbing up to 56% of the flux…
GJ 436b is a prime target for understanding warm Neptune exoplanet atmospheres and a target for multiple JWST GTO programs. Here, we report the first space-based optical transmission spectrum of the planet using two HST/STIS transit…
GJ 436b is a warm-- approximately 800 K--extrasolar planet that periodically eclipses its low-mass (half the mass of the Sun) host star, and is one of the few Neptune-mass planets that is amenable to detailed characterization. Previous…
Neptune-sized extrasolar planets that orbit relatively close to their host stars -- often called "hot Neptunes" -- are common within the known population of exoplanets and planetary candidates. Similar to our own Uranus and Neptune,…