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A low-mass star that is just 12 parsecs away from Earth is shown to be transited by an Earth-sized planet, GJ 1132b, which probably has a rock/iron composition and might support a substantial atmosphere. GJ1132b — a nearby rocky, Earth-sized planet Zachory Berta-Thompson et al . report observations of GJ 1132b, a 1.2 Earth radius planet transiting a small star only 12 parsecs away. The Doppler mass measurement of GJ 1132b yields a density consistent with an Earth-like rock/iron composition. The planet is too hot to be habitable but is cool enough to support a substantial atmosphere. Because the host star is nearby, existing and upcoming telescopes will be able to observe the composition and dynamics of the planetary atmosphere. M-dwarf stars—hydrogen-burning stars that are smaller than 60 per cent of the size of the Sun—are the most common class of star in our Galaxy and outnumber Sun-like stars by a ratio of 12:1. Recent results have shown that M dwarfs host Earth-sized planets in great numbers 1 , 2 : the average number of M-dwarf planets that are between 0.5 to 1.5 times the size of Earth is at least 1.4 per star 3 . The nearest such planets known to transit their star are 39 parsecs away 4 , too distant for detailed follow-up observations to measure the planetary masses or to study their atmospheres. Here we report observations of GJ 1132b, a planet with a size of 1.2 Earth radii that is transiting a small star 12 parsecs away. Our Doppler mass measurement of GJ 1132b yields a density consistent with an Earth-like bulk composition, similar to the compositions of the six known exoplanets with masses less than six times that of the Earth and precisely measured densities 5 , 6 , 7 , 8 , 9 , 10 , 11 . Receiving 19 times more stellar radiation than the Earth, the planet is too hot to be habitable but is cool enough to support a substantial atmosphere, one that has probably been considerably depleted of hydrogen. Because the host star is nearby and only 21 per cent the radius of the Sun, existing and upcoming telescopes will be able to observe the composition and dynamics of the planetary atmosphere.

A super-Earth with atmosphere 'Super-Earths' are extrasolar planets about two to ten times the mass of the Earth, too small to be considered 'Jupiters'. Observations from the MEarth Project — using two 40-cm (16-inch) telescopes that will eventually be part of an eight-telescope array — have now identified a super-Earth (GJ 1214b) transiting a nearby low mass star. GJ 1214b has a mass 6.55 times that of the Earth and a radius of 2.68 'Earths'. As the star is small and only 13 parsecs away, the planetary atmosphere is available for direct study with current observatories. A population of extrasolar planets has been uncovered with minimum masses of 1.9–10 times the Earth's mass, called super-Earths, but atmospheric studies can be precluded by the distance and size of their stars. Here, observations of the transiting planet GJ 1214b are reported; it has a mass 6.55 times that of the Earth and a radius 2.68 times the Earth's radius. The star is small and only 13 parsecs away, permitting the study of the planetary atmosphere with current observatories. A decade ago, the detection of the first 1 , 2 transiting extrasolar planet provided a direct constraint on its composition and opened the door to spectroscopic investigations of extrasolar planetary atmospheres 3 . Because such characterization studies are feasible only for transiting systems that are both nearby and for which the planet-to-star radius ratio is relatively large, nearby small stars have been surveyed intensively. Doppler studies 4 , 5 , 6 and microlensing 7 have uncovered a population of planets with minimum masses of 1.9–10 times the Earth’s mass ( M ⊕ ), called super-Earths. The first constraint on the bulk composition of this novel class of planets was afforded by CoRoT-7b (refs 8 , 9 ), but the distance and size of its star preclude atmospheric studies in the foreseeable future. Here we report observations of the transiting planet GJ 1214b, which has a mass of 6.55 M ⊕ and a radius 2.68 times Earth’s radius ( R ⊕ ), indicating that it is intermediate in stature between Earth and the ice giants of the Solar System. We find that the planetary mass and radius are consistent with a composition of primarily water enshrouded by a hydrogen–helium envelope that is only 0.05% of the mass of the planet. The atmosphere is probably escaping hydrodynamically, indicating that it has undergone significant evolution during its history. The star is small and only 13 parsecs away, so the planetary atmosphere is amenable to study with current observatories.

Background: Many planetary nebulae retain significant quantities of molecular gas and dust despite their signature hostile radiation environments and energetic shocks. Photoionization and dissociation by extreme UV and (often) X-ray emission from their central stars drive the chemical processing of this material. Their well-defined geometries make planetary nebulae ideal testbeds for modeling the effects of radiation-driven heating and chemistry on molecular gas in photodissociation regions. Methods: We have carried out IRAM 30m/APEX 12m/ALMA radio studies of the Helix Nebula and its molecule-rich globules, exploiting the unique properties of the Helix to follow up our discovery of an anti-correlation between HNC/HCN line intensity ratio and central star UV Luminosity. Results: Analysis of HNC/HCN across the Helix Nebula reveals the line ratio increases with distance from the central star, and thus decreasing incident UV flux, indicative of the utility of the HNC/HCN ratio as a tracer of UV irradiation in photodissociation environments. However, modeling of the observed regions suggests HNC/HCN should decrease with greater distance, contrary to the observed trend. Conclusion: HNC/HCN acts as an effective tracer of UV irradiation of cold molecular gas. Further model studies are required.

An Earth-sized planet is observed orbiting a nearby star within the liquid-water, habitable zone, the atmospheric composition of which could be determined from future observations. Super-Earth rocks around cool star Planets cause a dip in the light received when they pass in front of their parent stars. M stars have masses less than 60 per cent that of the Sun, and account for three-quarters of our Galaxy's stellar population. Seven Earth-sized planets are known to transit such a star, TRAPPIST-1, at 12 parsecs from Earth, but their masses and therefore their densities are rather poorly constrained. Jason Dittman et al . report observations of LHS 1140b, a planet with a radius 1.4 times that of Earth that is transiting an M dwarf star 12 parsecs from Earth and receiving sufficient insolation to place it in the liquid-water, 'habitable zone'. They measure the mass to be 6.6 times that of Earth, which suggests a rocky bulk composition. M dwarf stars, which have masses less than 60 per cent that of the Sun, make up 75 per cent of the population of the stars in the Galaxy 1 . The atmospheres of orbiting Earth-sized planets are observationally accessible via transmission spectroscopy when the planets pass in front of these stars 2 , 3 . Statistical results suggest that the nearest transiting Earth-sized planet in the liquid-water, habitable zone of an M dwarf star is probably around 10.5 parsecs away 4 . A temperate planet has been discovered orbiting Proxima Centauri, the closest M dwarf 5 , but it probably does not transit and its true mass is unknown. Seven Earth-sized planets transit the very low-mass star TRAPPIST-1, which is 12 parsecs away 6 , 7 , but their masses and, particularly, their densities are poorly constrained. Here we report observations of LHS 1140b, a planet with a radius of 1.4 Earth radii transiting a small, cool star (LHS 1140) 12 parsecs away. We measure the mass of the planet to be 6.6 times that of Earth, consistent with a rocky bulk composition. LHS 1140b receives an insolation of 0.46 times that of Earth, placing it within the liquid-water, habitable zone 8 . With 90 per cent confidence, we place an upper limit on the orbital eccentricity of 0.29. The circular orbit is unlikely to be the result of tides and therefore was probably present at formation. Given its large surface gravity and cool insolation, the planet may have retained its atmosphere despite the greater luminosity (compared to the present-day) of its host star in its youth 9 , 10 . Because LHS 1140 is nearby, telescopes currently under construction might be able to search for specific atmospheric gases in the future 2 , 3 .

Understanding how cool stars produce magnetic fields within their interiors is crucial for predicting the impact of such fields, such as the activity cycle of the Sun. In this respect, studying fully convective stars enables us to investigate the role of convective zones in magnetic field generation. We produced a magnetic map of a rapidly rotating, very-low-mass, fully convective dwarf through tomographic imaging from time series of spectropolarimetric data. Our results, which demonstrate that fully convective stars are able to trigger axisymmetric large-scale poloidal fields without differential rotation, challenge existing theoretical models of field generation in cool stars.

We present early results from our program of ALMA Band 6 (1.3mm) molecular line mapping of a sample of nearby, well-studied examples of high-excitation, bipolar/pinched-waist and molecule-rich planetary nebulae (Hubble 5 and NGC 2440, 2818, 2899, 6302, and 6445). We have mapped these planetary nebulae (PNe) in isotopologues of CO as well as various molecular line tracers of high-energy irradiation, such as HCN, CN, HNC, and HCO+, with the complementary goals of establishing nebular kinematics as well as the zones of UV-heated and X-ray-ionized molecular gas within each nebula. The resulting high-resolution ALMA molecular emission-line maps reveal the regions of high-excitation bipolar PNe in which molecular gas, presumably ejected during asymptotic giant branch stages of the PN progenitor stars, survives and evolves chemically. We present a summary of molecular species detected to date in the sample nebulae, and we use example results for one PN (NGC 6455) to demonstrate the power of the ALMA data in revealing the structures, kinematics, and compositions of the equatorial molecular tori that are a common feature of the sample objects.

We used multiple epochs of high-contrast imaging spectrophotometric observations to determine the atmospheric characteristics and thermal evolution of two previously detected benchmark L dwarf companions, HD 112863 B and HD 206505 B. We analyzed IRDIS and IFS data from VLT/SPHERE of each companion, both of which have dynamical masses near the stellar-substellar boundary. We compared each companion with empirical spectral standards, as well as constrained their physical properties through atmospheric model fits. From these analyses, we estimate that HD 112863 B is spectral type \\(\\rm{L}3\\pm1\\) and that HD 206505 B is spectral type \\(\\rm{L}2\\pm1\\). Using the BT-Settl atmospheric model grids, we find a bimodal solution for the atmospheric model fit of HD 112863 B, such that \\(T_{\\rm{eff}}=1757^{+37}_{-36}\\) K or \\(2002^{+23}_{-24}\\) K and \\(\\log{g}=4.973^{+0.057}_{-0.063}\\) or \\(5.253^{+0.037}_{-0.033}\\), while for HD 206505 B, \\(T_{\\rm{eff}}=1754^{+13}_{-13}\\) K and \\(\\log{g}=4.919^{+0.031}_{-0.029}\\). Comparing the bolometric luminosities of both companions with evolutionary models imply that both companions are likely above the hydrogen burning limit.

If it is commonly agreed that the presence of a (moderately) close stellar companion affects the formation and the dynamical evolution of giant planets, the frequency of giant planets residing in binary systems separated by less than 100 AU is unknown. To address this issue, we have conducted with VLT/NACO a systematic adaptive optics search for moderately close stellar companions to 130 nearby solar-type stars. According to the data from Doppler surveys, half of our targets host at least one planetary companion, while the other half show no evidence for short-period giant planets. We present here the final results of our survey, which include a new series of second-epoch measurements to test for common proper motion. The new observations confirm the physical association of two companion candidates and prove the unbound status of many others. These results strengthen our former conclusion that circumstellar giant planets are slightly less frequent in binaries with mean semimajor axes between 35 and 100 AU than in wider systems or around single stars.

Context. In the search for exoplanets using radial velocities (RV), stellar activity has become one of the main limiting factors for detectability. Fortunately, activity-induced RV signals are wavelength-dependent or chromatic, unlike planetary signals. This study exploits the broad spectral coverage provided by the combined use of SOPHIE and SPIRou velocimeters to investigate the chromatic nature of the activity signal of the highly active M dwarf EV Lac. Aims. We aim to understand the origin of the strong wavelength dependence (chromaticity) observed in the RV signal of EV Lac by selecting spectral lines based on physical properties. In particular, we explore the impact of starspots by defining the contrast effect at the level of individual lines. The Zeeman effect is also considered in this study. Methods. SPIRou and SOPHIE spectra were reduced using the line-by-line (LBL) method. We performed custom RV calculations, using groups of spectral lines selected for their sensitivity to either the spot-to-photosphere contrast or the Zeeman effect. The sensi- tivity of each line to the spot is defined using a two-temperature model based on PHOENIX spectra, while Landé factors were used to quantify Zeeman sensitivity. Results. We find that the spectral lines are distributed in two distinct families of contrasts, producing anti-correlated RV signals. This leads to a partial cancellation of the total RV signal, especially at longer wavelengths and provides a natural explanation for the strong chromaticity observed in EV Lac. This sign-reversal effect is demonstrated here, for the first time, on empirical data. Building on this discovery, we propose a new approach to constraining spot temperatures and to mitigating stellar activity. This will open up promising avenues for improving activity corrections and enhancing the detection of exoplanets around active M dwarfs.

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 d, the transiting sub-Neptune GJ 3090 b has a mass we refine to \\(4.52 \\pm 0.47 M_{\\oplus}\\), which, combined with our derived radius of \\(2.18 \\pm 0.06 R_{\\oplus}\\), yields a density of \\(2.40^{+0.33}_{-0.30}\\) g cm\\(^{-3}\\). The combined interior structure and atmospheric constraints indicate that GJ 3090 b is a compelling water-world candidate, with a volatile-rich envelope in which water likely represents a significant fraction. We also confirm the presence of a second planet, GJ 3090 c, a sub-Neptune with a 15.9 d orbit and a minimum mass of \\(10.0 \\pm 1.3 M_{\\oplus}\\), which does not transit. Despite its proximity to the star's 18 d rotation period, our joint analysis using a multidimensional Gaussian process (GP) model that incorporates TESS photometry and differential stellar temperature measurements distinguishes this planetary signal from activity-induced variability. In addition, we place new constraints on a non-transiting planet candidate with a period of 12.7 d, suggested in earlier RV analyses. This candidate remains a compelling target for future monitoring. These results highlight the crucial role of multidimensional GP modelling in disentangling planetary signals from stellar activity, enabling the detection of a planet near the stellar rotation period that could have remained undetected with traditional approaches.