We present results derived from the first multi-chord stellar occultation by the trans-Neptunian object (229762) 2007 UK₁₂₆, observed on 2014 November 15. The event was observed by the Research and Education Collaborative Occultation Network project and International Occultation Timing Association collaborators throughout the United States. Use of two different data analysis methods obtain a satisfactory fit to seven chords, yielding an elliptical fit to the chords with an equatorial radius of km and equivalent radius of km. A circular fit also gives a radius of km. Assuming that the object is a Maclaurin spheroid with indeterminate aspect angle, and using two published absolute magnitudes for the body, we derive possible ranges for geometric albedo between and , and for the body oblateness between and . For a nominal rotational period of 11.05 hr, an upper limit for density of ρ = 1740 kg m⁻³ is estimated for the body.

Context.Several planetary formation models have been proposed to explain the observed abundance and variety of compositions of super-Earths and mini-Neptunes. In this context, multitransiting systems orbiting low-mass stars whose planets are close to the radius valley are benchmark systems, which help to elucidate which formation model dominates.Aims.We report the discovery, validation, and initial characterization of one such system, TOI-2096 (TIC 142748283), a two-planet system composed of a super-Earth and a mini-Neptune hosted by a mid-type M dwarf located 48 pc away.Methods.We characterized the host star by combining optical spectra, analyzing its broadband spectral energy distribution, and using evolutionary models for low-mass stars. Then, we derived the planetary properties by modeling the photometric data from TESS and ground-based facilities. In addition, we used archival data, high-resolution imaging, and statistical validation to support our planetary interpretation.Results.We found that the stellar properties of TOI-2096 correspond to a dwarf star of spectral type M4±0.5. It harbors a super-Earth (R= 1.24 ± 0.07R_⊕) and a mini-Neptune (R= 1.90 ± 0.09R_⊕) in likely slightly eccentric orbits with orbital periods of 3.12 d and 6.39 d, respectively. These orbital periods are close to the first-order 2:1 mean-motion resonance (MMR), a configuration that may lead to measurable transit timing variations (TTVs). We computed the expected TTVs amplitude for each planet and found that they might be measurable with high-precision photometry delivering mid-transit times with accuracies of ≲2 min. Moreover, we conclude that measuring the planetary masses via radial velocities (RVs) could also be possible. Lastly, we found that these planets are among the best in their class to conduct atmospheric studies using the NIRSpec/Prism onboard theJames WebbSpace Telescope (JWST).Conclusions.The properties of this system make it a suitable candidate for further studies, particularly for mass determination using RVs and/or TTVs, decreasing the scarcity of systems that can be used to test planetary formation models around low-mass stars.

Context. Since the discovery of the first exoplanet almost three decades ago, the number of known exoplanets has increased dramatically. By beginning of the 2000s it was clear that dedicated facilities to advance our studies in this field were needed. The CHaracterising ExOPlanet Satellite (CHEOPS) is a space telescope specifically designed to monitor transiting exoplanets orbiting bright stars. In September 2023, CHEOPS completed its nominal mission duration of 3.5 yr and remains in excellent operational conditions. As a testament to this, the mission has been extended until the end of 2026. Aims. Scientific and instrumental data have been collected throughout in-orbit commissioning and nominal operations, enabling a comprehensive analysis of the mission’s performance. In this article, we present the results of this analysis with a twofold goal. First, we aim to inform the scientific community about the present status of the mission and what can be expected as the instrument ages. Secondly, we intend for this publication to serve as a legacy document for future missions, providing insights and lessons learned from the successful operation of CHEOPS. Methods. To evaluate the instrument performance in flight, we developed a comprehensive monitoring and characterisation (M&C) programme. It consists of dedicated observations that allow us to characterise the instrument’s response and continuously monitor its behaviour. In addition to the standard collection of nominal science and housekeeping data, these observations provide valuable input for detecting, modelling, and correcting instrument systematics, discovering and addressing anomalies, and comparing the instrument’s actual performance with expectations. Results. The precision of the CHEOPS measurements has enabled the mission objectives to be met and exceeded. The satellite’s performance remains stable and reliable, ensuring accurate data collection throughout its operational life. Careful modelling of the instrumental systematics allows the data quality to be significantly improved during the light curve analysis phase, resulting in more precise scientific measurements. Conclusions. CHEOPS is compliant with the driving scientific requirements of the mission. Although visible, the ageing of the instrument has not affected the mission’s performance. The satellite’s capabilities remain robust, and we are confident that we will continue to acquire high-quality data during the mission extension.

Planetary nebulae (PNs) consist of an ionized envelope surrounding a hot central star (CSPN) that emits mostly at ultraviolet (UV) wavelengths. UV observations, therefore, provide important information on both the CSPN and the nebula. We have matched the PNs in the Hong Kong/Australian Astronomical Observatory/Strasbourg Hα catalog with the Galaxy Evolution Explorer (GALEX) UV sky surveys, the Sloan Digital Sky Survey (SDSS) data release 16, and the Panoramic Survey Telescope and Rapid Response System (Pan-STARRS) PS1 second release. A total of 671 PNs were observed by GALEX with the far-UV (FUV; 1344 Å–1786 Å) and/or the near-UV (NUV; 1771 Å–2831 Å) detectors on (GUVPNcat); 83 were observed by SDSS (PNcatxSDSSDR16) and 1819 by Pan-STARRS (PNcatxPS1MDS). We merged a distilled version of these matched catalogs into GUVPNcatxSDSSDR16xPS1MDS, which contains a total of 375 PNs with both UV and optical photometry over a total spectral coverage of ∼1540 Å–9610 Å. We analyzed separately 170 PNs resolved in GALEX images and determined their UV radius by applying a flux profile analysis. The CSPN flux could be extracted separately from the PN emission for 8 and 50 objects with SDSS and Pan-STARRS counterparts, respectively. The multiband photometry was used to distinguish between compact and extended PNs and CSPNs (binary CSPNs) by color–color diagram analysis. We found that compact PN candidates could be identified by using the r − i < − 0.4 and −1 < FUV−NUV < 1 colors, whereas binary CSPN candidates in given T _eff ranges (all with color r−i > −0.4) can be identified in the color region (FUV−NUV) ≤ 6(r−i)+1.3, −0.8 < FUV−NUV < 0.4, and r−i < 0.75.

We investigated the origin of the Planetary Nebula (PN) M 1–16 using narrow-band optical imaging, and high- and low-resolution optical spectra to perform a detailed morpho-kinematic and chemical studies. M 1–16 is revealed to be a multipolar PN that predominantly emits in [O III] in the inner part of the nebula and [N II] in the lobes. A novel spectral unsharp masking technique was applied to the position-velocity (PV) maps to reveal a set of multiple structures at the centre of M 1–16 spanning radial velocities from −40 km s⁻¹ to 20 km s⁻¹, with respect to the systemic velocity. The morpho-kinematic model indicates that the deprojected velocity of the lobe outflows are ≥100 km s⁻¹, and particularly the larger lobes and knots have a deprojected velocity of ≃350 km s⁻¹; the inner ellipsoidal component has a deprojected velocity of ≃29 km s⁻¹. A kinematical age of ~8700 yr has been obtained from the model assuming a homologous velocity expansion law and a distance of 6.2 ± 1.9 kpc. The chemical analysis indicates that M 1–16 is a Type I PN with a central star of PN (CSPN) mass in the range of ≃0.618 – 0.713 M_⊙ and an initial mass for the progenitor star between 2.0 and 3.0 M_⊙ (depending on metallicity). An T_eff ≃ 140 000 K and log(L/L_⊙) = 2.3 was estimated using the 3MdB photoionisation models to reproduce the ionisation. stage of the PN. All of these results have led us to suggest that M 1–16 is an evolved PN, contrary to the scenario of proto-PN suggested in previous studies. We propose that the mechanism responsible for the morphology of M 1–16 is related to the binary (or multiple star) evolution scenario.

With its bright and wide equatorial waist seen almost edge-on (“the butterfly body”) and the faint and broad bipolar extensions (“the butterfly wings”), NGC 650-1 is the archetypical example of bipolar planetary nebula (PN) with butterfly morphology. We present here deep high-resolution broad- and narrow-band optical images that expose the rich and intricate fine-structure of this bipolar PN, with small-scale bubble-like features and collimated outflows. A SHAPE spatio-kinematic model indicates that NGC 650-1 has a broad central torus with an inclination angle of 75° with respect to the line of sight, whereas that of the bipolar lobes, which are clearly seen in the position-velocity maps, is 85°. Large field of view deep images show, for first time, an arc-like diffuse envelope in low- and high-excitation emission lines located up to 180″ towards the East-Southeast of the central star, well outside the main nebula. This morphological component is confirmed by Spitzer MIPS and WISE infrared imaging, as well as by long-slit low- and high-dispersion optical spectroscopic observations. HST images of NGC 650-1 obtained at two different epochs ∼14 yrs apart reveal the proper motion of the central star along this direction. We propose that this motion of the star through the interstellar medium compresses the remnant material of a slow Asymptotic Giant Branch wind, producing this bow-shock-like feature.