Related papers: On the GJ 436 planetary system
(Abridged) The quiet M2.5 star GJ 436 hosts a warm Neptune that displays an extended atmosphere that dwarfs its own host star. Predictions of atmospheric escape in such planets state that H atoms escape from the upper atmosphere in a…
GJ 436b is the first extrasolar planet discovered that resembles Neptune in mass and radius. The particularly interesting property of Neptune-sized planets is that their mass Mp and radius Rp are close to theoretical M-R relations of water…
Hot Neptunes, gaseous planets smaller than Saturn ($\sim$ 3-8 R$_\oplus$) with orbital periods less than 10 days, are rare. Models predict this is due to high-energy stellar irradiation stripping planetary atmospheres over time, often…
We study the dynamical stability of an additional, potentially habitable planet in the HD 47186 planetary system. Two planets are currently known in this system: a "hot Neptune" with a period of 4.08 days and a Saturn-mass planet with a…
The nearby M2 dwarf GJ 3470 has been the target of considerable interest after the discovery of a transiting short-period Neptune-sized planet. Recently, claims regarding the existence of additional transiting planets has gotten some…
We re-analyze the precision radial velocity (RV) data of HD188015, HD114729, HD190360, HD147513 and HD208487. All these stars are supposed to host Jovian companions in long-period orbits. We test a hypothesis that the residuals of the…
We present high spectral resolution $L$ band (2.91--3.85 $\mu$m) observations of the warm Neptune GJ 436 b from Keck II/KPIC. KPIC's single-mode fiber feed reduces the $L$ band sky background by a factor of 100, significantly improving…
Variability in the far ultraviolet (FUV) emission produced by stellar activity affects photochemistry and heating in orbiting planetary atmospheres. We present a comprehensive analysis of the FUV variability of GJ 436, a field-age, M2.5V…
We present precision radial velocity (RV) data that reveal a multiple exoplanet system orbiting the bright nearby G5V star 61 Virginis. Our 4.6 years of combined Keck/HIRES and Anglo-Australian Telescope precision RVs indicate the hitherto…
We investigate the dynamical evolution of the potentially habitable super-earth GJ 667Cc in the multiple system of at least two exoplanets orbiting a nearby M dwarf, paying special attention to its spin-orbital state. The published radial…
We present Spitzer Space Telescope infrared photometry of a primary transit of the hot Neptune GJ 436b. The observations were obtained using the 8 microns band of the InfraRed Array Camera (IRAC). The high accuracy of the transit data and…
We present an updated characterization of the planetary system orbiting the nearby M2 dwarf GJ 3090 (TOI-177; $d = 22$ pc), based on new high-precision radial velocity (RV) observations from NIRPS and HARPS. With an orbital period of 2.85…
GJ4276 is an M4.0 dwarf star with an inferred Neptune mass planet from radial velocity (RV) observations. We reanalyse the RV data for this system and focus on the possibility of a second, super earth mass, planet. We compute the timescale…
Ahead of upcoming space missions intending to conduct observations of low-mass stars in the ultraviolet (UV) spectral region it becomes imperative to simultaneously conduct atmospheric modeling from the UV to the visible (VIS) and…
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…
We announce the discovery of a planetary system with 7 transiting planets around a Kepler target, a current record for transiting systems. Planets b, c, e and f are reported for the first time in this work. Planets d, g and h were…
Over the past two years, the search for low-mass extrasolar planets has led to the detection of seven so-called 'hot Neptunes' or 'super-Earths' around Sun-like stars. These planets have masses 5-20 times larger than the Earth and are…
The transiting hot Jupiter planet Qatar-1 b was presented to exhibit variations in transit times that could be of perturbative nature. A hot Jupiter with a planetary companion on a nearby orbit would constitute an unprecedented planetary…
About one out of 200 Sun-like stars has a planet with an orbital period shorter than one day: an ultra-short-period planet (Sanchis-ojeda et al. 2014; Winn et al. 2018). All of the previously known ultra-short-period planets are either hot…
Transiting planets with orbital periods longer than 40 d are extremely rare among the 5000+ planets discovered so far. The lack of discoveries of this population poses a challenge to research into planetary demographics, formation, and…