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Late-stage Ca-sulfate-filled fractures are common on Mars. Notably, the Shenandoah formation in the western edge of Jezero crater preserves a variety of Ca-sulfate minerals in the fine-grained siliciclastic rocks explored by the Perseverance rover. However, the depositional environment and timing of the formation of these sulfates is unknown. To address this outstanding problem, we developed a new technique to map the crystal textures of these sulfates in situ at two stratigraphically similar locations in the Shenandoah formation, allowing us to constrain the burial depth and paleoenvironment at the time of their deposition. Our results suggest that some Ca-sulfate analyzed was formed at a burial depth greater than 80m, whereas Ca-sulfates present at another outcrop likely precipitated in a shallow-subsurface environment. These results indicate that samples collected for potential return to Earth at the two studied locations capture two different times and distinct chemical conditions in the depositional history of the Shenandoah formation providing multiple opportunities to evaluate surface and subsurface habitability.

Pebbles drifting past a disk-embedded low-mass planet develop asymmetries in their distribution and exert a substantial gravitational torque on the planet, thus modifying its migration rate. Our aim is to assess how the distribution of pebbles and the resulting torque change in the presence of pebble accretion, focusing on its 2D regime. First, we performed 2D high-resolution multi-fluid simulations with Fargo3D but found that they are impractical for resolving pebble accretion due to the smoothing of the planetary gravitational potential. To remove the smoothing and directly trace pebbles accreted by the planet, we developed a new code, Deneb, which evolves an ensemble of pebbles, represented by Lagrangian superparticles, in a steady-state gaseous background. For small and moderate Stokes numbers, St $\lesssim 0.1$, pebble accretion creates two underdense regions with a front-rear asymmetry with respect to the planet. The underdensity trailing the planet is more extended. The resulting excess of pebble mass in front of the planet then makes the pebble torque positive and capable of outperforming the negative gas torque. Pebble accretion thus enables outward migration (previously thought to occur mainly for St $\gtrsim 0.1$) in a larger portion of the parameter space. It occurs for the planet mass $M_{pl}\lesssim3\,M_{\oplus}$ and for all the Stokes numbers considered in our study, St $\in$ [$10^{-2}, 0.785$], assuming a pebble-to-gas mass ratio of $Z = 0.01$. If some of the observed planets underwent outward pebble-driven migration during their accretion, the formation sites of their progenitor embryos could have differed greatly from the usual predictions of planet formation models. To enable an update of the respective models, we provide a scaling law for the pebble torque that can be readily incorporated in N-body simulations., Comment: Published in A&A

The proper elements of asteroids are obtained from the instantaneous orbital elements by removing periodic oscillations produced by gravitational interactions with planets. They are unchanging in time, at least if chaotic dynamics and non-gravitational forces could be ignored, and can therefore be used to identify fragments of major collisions (asteroid families) that happened eons ago. Here we present a new catalog of proper elements for 1.25 million main belt asteroids. We explain the methodology, evaluate uncertainties, and discuss how the new catalog can be used to identify asteroid families. A systematic search for families yielded 153 cases not reported in Nesvorn\'y at al. (2015) -- 17 of these cases were identified in various other publications, 136 cases are new discoveries. There are now 274 families in the asteroid belt in total (plus a handful of families in the resonant Hilda population). We analyzed several compact families in detail. The new family around the middle belt asteroid (9332) 1990SB1 (9 members) is the youngest family found so far (estimated formation only 16-17 kyr ago). New families (1217) Maximiliana, (6084) Bascom, (10164) Akusekijima and (70208) 1999RX33 all formed 0.5-2.5 Myr ago. The (2110) Moore-Sitterly family is a close pair of relatively large bodies, 2110 and 44612, and 15 small members all located sunwards from 2110 and 44612, presumably a consequence of the Yarkovsky drift over the estimated family age (1.2-1.5 Myr). A systematic characterization of the new asteroid families is left for future work., Comment: ApJS, in press

The present work aims to determine the source regions of carbonaceous chondrites (CM, CI, CO, CV, CK, CR, CH, CB, or C-ungrouped). We studied 38 individual asteroid families, including young and old ones, and determined their contributions to the NEO populations at metre and kilometre sizes using collisional and orbital models. Our models are in agreement with spectroscopic observations of NEOs, cosmic-ray exposure ages of meteorites, statistics of bolides, infrared emission from dust bands, composition of interplanetary dust particles (IDPs), or abundance of extraterrestrial helium-3. We identified the Veritas, Polana and Eos families as the primary sources of CM/CR, CI and CO/CV/CK chondrites, respectively. Substantial contributions are also expected from CM-like K\"onig and CI-like Clarissa, Misa and Hoffmeister families. The source regions of kilometre-sized bodies are generally different. The Adeona family is by far the main source of CM-like NEOs, whereas the Polana (low-i) and Euphrosyne (high-i) families are at the origin of most CI-like NEOs. The Polana family is the likely source of both Ryugu and Bennu. We were able to link spectroscopically and dynamically several NEOs to the Baptistina family. Finally, it appears that the pre-atmospheric flux of carbonaceous chondrites at metre sizes is about the same as that of ordinary chondrites. Given the difference in fall statistics between the two groups (80\% versus 4.4\%), this implies either substantial atmospheric fragmentation of carbonaceous bodies at the level of ${\sim}0.5\,{\rm MPa}$, or destruction by thermal cracking and water desorption. The source regions of most meteorites and kilometre-sized NEOs have now been determined; including some minor classes like enstatite chondrites and achondrites (Nysa, Hungaria), acapulcoites/lodranites (Iannini)., Comment: 47 pages, 31 figures, accepted in A&A

Reliable control of quantum information in matter-based qubits requires precisely applied external fields, and unaccounted for spatial cross-talk of these fields between adjacent qubits leads to loss of fidelity. We report a CMOS foundry-produced, micro-fabricated silicon nitride (Si3N4) optical waveguide for addressing a chain of eight, unequally-spaced trapped barium ions with crosstalk compatible with scalable quantum information processing. The crosstalk mitigation techniques incorporated into the chip design result in a reduction of the measured optical field by at least 50.8(1.3) dB between adjacent waveguide outputs near 650 nm and similar behavior for devices designed for 493 nm and 585 nm. The waveguide outputs near 650 nm, along with a global laser near 493 nm were used to laser-cool a chain of eight barium-138 ions, and a camera imaged the resulting fluorescence at 493 nm., Comment: 9 pages, 7 figures

We demonstrate coherent control of a three-electron exchange-only spin qubit with the quantum dots arranged in a close-packed triangular geometry. The device is tuned to confine one electron in each quantum dot, as evidenced by pairwise charge stability diagrams. Time-domain control of the exchange coupling is demonstrated and qubit performance is characterized using blind randomized benchmarking, with an average single-qubit gate fidelity F = 99.84%. The compact triangular device geometry can be readily scaled to larger two-dimensional quantum dot arrays with high connectivity.

Understanding the origin of bright shooting stars and their meteorite samples is among the most ancient astronomy-related questions that at larger scales has human consequences [1-3]. As of today, only ${\sim}\,6\%$ of meteorite falls have been firmly linked to their sources (Moon, Mars, and asteroid (4) Vesta [4-6]). Here, we show that ${\sim}\,70\%$ of meteorites originate from three recent breakups of $D > 30\,{\rm km}$ asteroids that occurred 5.8, 7.5 and less than ${\sim}\,40$ million years ago. These breakups, including the well-known Karin family [7], took place in the prominent yet old Koronis and Massalia families and are at the origin of the dominance of H and L ordinary chondrites among meteorite falls. These young families distinguish themselves amidst all main belt asteroids by having a uniquely high abundance of small fragments. Their size-frequency distribution remains steep for a few tens of millions of years, exceeding temporarily the production of metre-sized fragments by the largest old asteroid families (e.g., Flora, Vesta). Supporting evidence includes the existence of associated dust bands [8-10], the cosmic-ray exposure ages of H-chondrite meteorites [11,12], or the distribution of pre-atmospheric orbits of meteorites [13-15]., Comment: 69 pages, 24 figures

Studies of micrometeorites in mid-Ordovician limestones and Earth's impact craters indicate that our planet witnessed a massive infall of ordinary L chondrite material 466 million years (My) ago (Heck et al. 2017, Schmieder & Kring 2020, Kenkmann 2021) that may have been at the origin of the first major mass extinction event (Schmitz et al. 2019). The breakup of a large asteroid in the main belt is the likely cause of this massive infall. In modern times, material originating from this breakup still dominates meteorite falls (>20% of all falls) (Swindle et al. 2014). Here, we provide spectroscopic observations and dynamical evidence that the Massalia collisional family is the only plausible source of this catastrophic event and of the most abundant class of meteorites falling on Earth today. It is suitably located in the inner belt, at low-inclination orbits, which corresponds to the observed distribution of L-chondrite-like near-Earth objects (NEOs) and of interplanetary dust concentrated at 1.4 degrees (Sykes 1990, Reach et al. 1997)., Comment: 35 pages, 11 pages, under revision

Jupiter Trojans (JTs) librate about the Lagrangian stationary centers L4 and L5 associated with this planet on a typically small-eccentricity and moderate-inclination heliocentric orbits. The physical and orbital properties of JTs provide important clues about the dynamical evolution of the giant planets in the early Solar System, as well as populations of planetesimals in their source regions. Here we use decade long observations from the Catalina Sky Survey (station G96) to determine the bias-corrected orbital and magnitude distributions of JTs. We distinguish the background JT population, filling smoothly the long-term stable orbital zone about L4 and L5 points, and collisional families. We find that the cumulative magnitude distribution of JTs (the background population in our case) has a steep slope for $H\leq 9$, followed with a moderately shallow slope till $H\simeq 14.5$, beyond which the distribution becomes even shallower. At $H=15$ we find a local power-law exponent $0.38\pm 0.01$. We confirm the asymmetry between the magnitude limited background populations in L4 and L5 clouds characterized by a ratio $1.45\pm 0.05$ for $H<15$. Our analysis suggests an asymmetry in the inclination distribution of JTs, with the L4 population being tighter and the L5 population being broader. We also provide a new catalog of the synthetic proper elements for JTs with an updated identification of statistically robust families (9 at L4, and 4 at L5). The previously known Ennomos family is found to consist of two, overlapping Deiphobus and Ennomos families., Comment: 46 pages, 36 figures, 4 tables, accepted for publication in The Astronomical Journal

This abstract presents a scenario for human-robot action in a home setting involving an older adult and a robot. The scenario is designed to explore the envisioned modelling of memory for communication with a socially assistive robots (SAR). The scenario will enable the gathering of data on failures of speech technology and human-robot communication involving shared memory that may occur during daily activities such as a music-listening activity., Comment: In WTF Workshop Proceedings (arXiv:2401.04108) held in conjunction with the ACM conference on Conversational User Interfaces (CUI), 19 - 21/07 2023, in Eindhoven, The Netherlands

We use observations from the Catalina Sky Survey (CSS) to determine the bias-corrected population of small members in four very young families down to sizes equivalent to several hundred meters. Using the most recent catalog of known asteroids, we identified members from four young families for which the population has grown appreciably over recent times. A large fraction of these bodies have also been detected by CSS. We used synthetic populations of asteroids, with their magnitude distribution controlled by a small number of parameters, as a template for the bias-corrected model of these families. Applying the known detection probability of the CSS observations, we could adjust these model parameters to match the observed (biased) populations in the young families. In the case of three families, Datura, Adelaide, and Rampo, we find evidence that the magnitude distribution transitions from steep to shallow slopes near $300$ to $400$ meters. Conversely, the Hobson family population may be represented by a single power-law model. The Lucascavin family has a limited population; no new members have been discovered over the past two decades. We consider a model of parent body rotational fission with the escaping secondary tidally split into two components (thereby providing three members within this family). In support of this idea, we find that no other asteroid with absolute magnitude $H\leq 18.3$ accompanies the known three members in the Lucascavin family. A similar result is found for the archetypal asteroid pair Rheinland--Kurpfalz., Comment: 32 pages, 27 figures, accepted for publication in Astronomy and Astrophysics

The Ch-type asteroid (130) Elektra is orbited by three moons, making it the first quadruple system in the main asteroid belt. We aim to characterise the irregular shape of Elektra and construct a complete orbital model of its unique moon system. We applied the All-Data Asteroid Modelling (ADAM) algorithm to 60 light curves of Elektra, including our new measurements, 46 adaptive-optics (AO) images obtained by the VLT/SPHERE and Keck/Nirc2 instruments, and two stellar occultation profiles. For the orbital model, we used an advanced $N$-body integrator, which includes a multipole expansion of the central body (with terms up to the order $\ell = 6$), mutual perturbations, internal tides, as well as the external tide of the Sun acting on the orbits. We fitted the astrometry measured with respect to the central body and also relatively, with respect to the moons themselves. We obtained a revised shape model of Elektra with the volume-equivalent diameter $(201\pm 2)\,{\rm km}$. Out of two pole solutions, $(\lambda, \beta) = (189; -88)\,{\rm deg}$ is preferred, because the other one leads to an incorrect orbital evolution of the moons. We also identified the true orbital period of the third moon S/2014 (130) 2 as $P_2 = (1.642112 \pm 0.000400)\,{\rm d}$, which is in between the other periods, $P_1 \simeq 1.212\,{\rm d}$, $P_3 \simeq 5.300\,{\rm d}$, of S/2014 (130) 1 and S/2003 (130) 1, respectively. The resulting mass of Elektra, $(6.606 \substack{+0.007 \\ -0.013}) \times 10^{18}\,{\rm kg}$, is precisely constrained by all three orbits. Its bulk density is then $(1.536 \pm 0.038)\,{\rm g\,cm}^{-3}$. The expansion with the assumption of homogeneous interior leads to the oblateness $J_2 = -C_{20} \simeq 0.16$. However, the best-fit precession rates indicate a slightly higher value, ${\simeq}\,0.18$., Comment: 19 pages, 23 figures

We outline the impact of a small two-band UV-photometry satellite mission on the field of stellar physics, magnetospheres of stars, binaries, stellar clusters, interstellar matter, and exoplanets. On specific examples of different types of stars and stellar systems, we discuss particular requirements for such satellite missions in terms of specific mission parameters such as bandpass, precision, cadence, and mission duration. We show that such a mission may provide crucial data not only for hot stars that emit most of their light in UV, but also for cool stars, where UV traces their activity. This is important, for instance, for exoplanetary studies, because the level of stellar activity influences habitability. While the main asset of the two-band UV mission rests in time-domain astronomy, an example of open clusters proves that such a mission would be important also for the study of stellar populations. Properties of the interstellar dust are best explored when combining optical and IR information with observations in UV. It is well known that dust absorbs UV radiation efficiently. Consequently, we outline how such a UV mission can be used to detect eclipses of sufficiently hot stars by various dusty objects and study disks, rings, clouds, disintegrating exoplanets or exoasteroids. Furthermore, UV radiation can be used to study the cooling of neutron stars providing information about the extreme states of matter in the interiors of neutron stars and used for mapping heated spots on their surfaces., Comment: Accepted for publication in Space Science Reviews; corrected version including comments of the referee

Near Earth Objects (NEOs) are a transient population of small bodies with orbits near or in the terrestrial planet region. They represent a mid-stage in the dynamical cycle of asteroids and comets, which starts with their removal from the respective source regions -- the main belt and trans-Neptunian scattered disk -- and ends as bodies impact planets, disintegrate near the Sun, or are ejected from the Solar System. Here we develop a new orbital model of NEOs by numerically integrating asteroid orbits from main belt sources and calibrating the results on observations of the Catalina Sky Survey. The results imply a size-dependent sampling of the main belt with the $\nu_6$ and 3:1 resonances producing $\simeq 30$\% of NEOs with absolute magnitudes $H = 15$ and $\simeq 80$\% of NEOs with $H = 25$. Hence, the large and small NEOs have different orbital distributions. The inferred flux of $H<18$ bodies into the 3:1 resonance can be sustained only if the main-belt asteroids near the resonance drift toward the resonance at the maximal Yarkovsky rate ($\simeq 2 \times 10^{-4}$ au Myr$^{-1}$ for diameter $D=1$ km and semimajor axis $a=2.5$~au). This implies obliquities $\theta \simeq 0^\circ$ for $a<2.5$~au and $\theta \simeq 180^\circ$ for $a>2.5$~au, both in the immediate neighborhood of the resonance (the same applies to other resonances as well). We confirm the size-dependent disruption of asteroids near the Sun found in previous studies. An interested researcher can use the publicly available NEOMOD Simulator to generate user-defined samples of NEOs from our model., Comment: AJ

The satellite Linus orbiting the main-belt asteroid (22) Kalliope exhibited occultation and transit events in late 2021. A photometric campaign was organized and observations were taken by the TRAPPIST-South, SPECULOOS-Artemis, OWL-Net, and BOAO telescopes, with the goal to constrain models of this system. Our dynamical model is complex, with multipoles (up to the order $\ell = 2$), internal tides, and external tides. The model was constrained by astrometry (spanning 2001--2021), occultations, adaptive-optics imaging, calibrated photometry, as well as relative photometry. Our photometric model was substantially improved. A new precise (${<}\,0.1\,{\rm mmag}$) light curve algorithm was implemented, based on polygon intersections, which are computed exactly -- by including partial eclipses and partial visibility of polygons. Moreover, we implemented a `cliptracing' algorithm, based again on polygon intersections, in which partial contributions to individual pixels are computed exactly. Both synthetic light curves and synthetic images are then very smooth. Based on our combined solution, we confirmed the size of Linus, $(28\pm 1)\,{\rm km}$. However, this solution exhibits some tension between the light curves and the PISCO speckle-interferometry dataset. In most solutions, Linus is darker than Kalliope, with the albedos $A_{\rm w} = 0.40$ vs. $0.44$. This is confirmed on deconvolved images. A~detailed revision of astrometric data allowed us to revise also the $J_2 \equiv -C_{20}$ value of Kalliope. Most importantly, a~homogeneous body is excluded. For a differentiated body, two solutions exist: low-oblateness ($C_{20} \simeq -0.12$), with a~spherical iron core, and alternatively, high-oblateness ($C_{20} \simeq -0.22$) with an elongated iron core. These correspond to the low- and high-energy collisions, respectively, studied by means of SPH simulations in our previous work., Comment: Astronomy and Astrophysics, accepted

Experiential AI is presented as a research agenda in which scientists and artists come together to investigate the entanglements between humans and machines, and an approach to human-machine learning and development where knowledge is created through the transformation of experience. The paper discusses advances and limitations in the field of explainable AI; the contribution the arts can offer to address those limitations; and methods to bring creative practice together with emerging technology to create rich experiences that shed light on novel socio-technical systems, changing the way that publics, scientists and practitioners think about AI., Comment: 10 pages, 3 appendices

We report the discovery with $TESS$ of a third set of eclipses from V994 Herculis (TIC 424508303), previously only known as a doubly-eclipsing system. The key implication of this discovery and our analyses is that V994 Her is the second fully-characterized (2+2) + 2 sextuple system, in which all three binaries eclipse. In this work, we use a combination of ground-based observations and $TESS$ data to analyze the eclipses of binaries A and B in order to update the parameters of the inner quadruple's orbit (with a derived period of 1062 $\pm$ 2d). The eclipses of binary C that were detected in the $TESS$ data were also found in older ground-based observations, as well as in more recently obtained observations. The eclipse timing variations of all three pairs were studied in order to detect the mutual perturbations of their constituent stars, as well as those of the inner pairs in the (2+2) core. At the longest periods they arise from apsidal motion, which may help constraining parameters of the component stars' internal structure. We also discuss the relative proximity of the periods of binaries A and B to a 3:2 mean motion resonance. This work represents a step forward in the development of techniques to better understand and characterize multiple star systems, especially those with multiple eclipsing components., Comment: Accepted for publication by MNRAS

$\delta$ Orionis is the closest massive multiple stellar system and one of the brightest members of the Orion OB association. The primary (Aa1) is a unique evolved O star. In this work, we applied a two-step disentangling method to a series of spectra in the blue region (430 to 450 nm), and we detected spectral lines of the secondary (Aa2). For the first time, we were able to constrain the orbit of the tertiary (Ab) - to 55 450 d or 152 yr - using variable $\gamma$ velocities and new speckle interferometric measurements, which have been published in the Washington Double Star Catalogue. In addition, the Gaia DR3 parallax of the faint component (Ca+Cb) constrains the distance of the system to (381 $\pm$ 8) pc, which is just in the centre of the Orion OB1b association, at (382 $\pm$ 1) pc. Consequently, we found that the component masses according to the three-body model are 17.8, 8.5, and 8.7 M$_{\odot}$, for Aa1, Aa2, and Ab, respectively, with the uncertainties of the order of $1$ M$_{\odot}$. We used new photometry from the BRITE satellites together with astrometry, radial velocities, eclipse timings, eclipse duration, spectral line profiles, and spectral energy distribution to refine radiative properties. The components, classified as O9.5 II + B2 V + B0 IV, have radii of 13.1, 4.1, and 12.0 R$_{\odot}$, which means that $\delta$ Ori A is a pre-mass-transfer object. The frequency of 0.478 cycles per day, known from the Fourier analysis of the residual light curve and X-ray observations, was identified as the rotation frequency of the tertiary. $\delta$ Ori could be related to other bright stars in Orion, in particular, $\zeta$ Ori, which has a similar architecture, or $\varepsilon$ Ori, which is a single supergiant, and possibly a post-mass-transfer object., Comment: 22 pages, 22 figures

Cybele asteroids constitute an appealing reservoir of primitive material genetically linked to the outer Solar System, and the physical properties of the largest members can be readily accessed by large telescopes. We took advantage of the bright apparition of (65) Cybele in July and August 2021 to acquire high-angular-resolution images and optical light curves of the asteroid with which we aim to analyse its shape and bulk properties. 7 series of images acquired with VLT/SPHERE were combined with optical light curves to reconstruct the shape of the asteroid using the ADAM, MPCD, and SAGE algorithms. The origin of the shape was investigated by means of N-body simulations. Cybele has a volume-equivalent diameter of 263+/-3km and a bulk density of 1.55+/-0.19g.cm-3. Notably, its shape and rotation state are closely compatible with those of a Maclaurin equilibrium figure. The lack of a collisional family associated with Cybele and the higher bulk density of that body with respect to other large P-type asteroids suggest that it never experienced any large disruptive impact followed by rapid re-accumulation. This would imply that its present-day shape represents the original one. However, numerical integration of the long-term dynamical evolution of a hypothetical family shows that it is dispersed by gravitational perturbations and chaotic diffusion over Gyrs of evolution. The very close match between Cybele and an equilibrium figure opens up the possibility that D>260km small bodies from the outer Solar System all formed at equilibrium. However, we cannot rule out an old impact as the origin of the equilibrium shape. Cybele itself is found to be dynamically unstable, implying that it was recently (<1Ga) placed on its current orbit either through slow diffusion from a relatively stable orbit in the Cybele region or, less likely, from an unstable, JFC orbit in the planet-crossing region., Comment: 19 pages, 14 figures, 4 tables, accepted for publication in A&A

Kaplan and Rajendran have recently demonstrated that non-linear and state-dependent terms can be consistently added to quantum field theory to yield causal non-linear time evolution in quantum mechanics. Causal non-linear theories have the unavoidable feature that their quantum effects are dramatically sensitive to the full physical spread of the quantum state of the system. As a result, such theories are not well tested by conventional atomic and nuclear spectroscopy. By using a well-controlled superposition of vibrational modes of a $^{40}$Ca$^+$ ion trapped in a harmonic potential, we set a stringent limit of $5.4\times 10^{-12}$ on the magnitude of the unitless scaling factor $\tilde{\epsilon}_{\gamma}$ for the predicted causal, non-linear perturbation.

HD 93206 is early-type massive stellar system, composed of components resolved by direct imaging (Ab, Ad, B, C, D) as well as a compact sub-system (Aa1, Aa2, Ac1, Ac2). Its geometry was already determined on the basis of extensive photometric, spectroscopic and interferometric observations. However, the fundamental absolute parameters are still not known precisely enough. We use an advanced N-body model to account for all mutual gravitational perturbations among the four close components, and all observational data types, including: astrometry, radial velocities, eclipse timing variations, squared visibilities, closure phases, triple products, normalized spectra, and spectral-energy distribution (SED). The respective model has 38 free parameters, namely three sets of orbital elements, component masses, and their basic radiative properties ($T$, $\log g$, $v_{\rm rot}$). We revised the fundamental parameters of QZ Car as follows. For a model with the nominal extinction coefficient $R_V \equiv A_V/E(B-V) = 3.1$, the best-fit masses are $m_1 = 26.1\,M_{\rm S}$, $m_2 = 32.3\,M_{\rm S}$, $m_3 = 70.3\,M_{\rm S}$, $m_4 = 8.8\,M_{\rm S}$, with uncertainties of the order of $2\,M_{\rm S}$, and the system distance $d = (2800\pm 100)\,{\rm pc}$. In an alternative model, where we increased the weights of RV and TTV observations and relaxed the SED constraints, because extinction can be anomalous with $R_V \sim 3.4$, the distance is smaller, $d = (2450\pm 100)\,{\rm pc}$. This would correspond to that of Collinder 228 cluster. Independently, this is confirmed by dereddening of the SED, which is only then consistent with the early-type classification (O9.7Ib for Aa1, O8III for Ac1). Future modelling should also account for an accretion disk around Ac2 component., Comment: A&A, submitted

According to adaptive-optics observations by Ferrais et al., (22) Kalliope is a 150-km, dense and differentiated body. Here, we interpret (22) Kalliope in the context of bodies in its surroundings. While there is a known moon Linus, with a 5:1 size ratio, no family has been reported in the literature, which is in contradiction with the existence of the moon. Using the hierarchical clustering method (HCM) along with physical data, we identified the Kalliope family. Previously, it was associated to (7481) San Marcello. We then used various models (N-body, Monte-Carlo, SPH) of its orbital and collisional evolution, including the break-up of the parent body, to estimate the dynamical age of the family and address its link to Linus. The best-fit age is (900+-100) My according to our collisional model, in agreement with the position of (22) Kalliope, which was modified by chaotic diffusion due to 4-1-1 three-body resonance with Jupiter and Saturn. It seems possible to create Linus and the Kalliope family at the same time, although our SPH simulations show a variety of outcomes, for both satellite size and the family size-frequency distribution. The shape of (22) Kalliope itself was most likely affected by gravitational reaccumulation of `streams', which creates characteristic hills observed on the surface. If the body was differentiated, its internal structure is surely asymmetric., Comment: A&A, accepted

We studied impact processes by means of smoothed-particle hydrodynamics (SPH) simulations. The method was applied to modeling formation of main-belt families during the cometary bombardment (either early or late, ${\sim}\,3.85\,{\rm Gy}$ ago). If asteroids were bombarded by comets, as predicted by the Nice model, hundreds of asteroid families (catastrophic disruptions of diameter $D \ge 100\,{\rm km}$ bodies) should have been created, but the observed number is only 20. Therefore we computed a standard set of 125 simulations of collisions between representative $D = 100\,{\rm km}$ asteroids and high-speed icy projectiles (comets). According to our results, the largest remnant mass $M_{\rm lr}$ is similar as in low-speed collisions, due to appropriate scaling with the effective strength $Q_{\rm eff}$, but the largest fragment mass $M_{\rm lf}$ exhibits systematic differences - it is typically smaller for craterings and bigger for super-catastrophic events. This trend does not, however, explain the non-existence of old families. The respective parametric relations can be used in other statistical (Monte-Carlo) models to better understand collisions between asteroidal and cometary populations.

Quantum Support Vector Machines (QSVM) have become an important tool in research and applications of quantum kernel methods. In this work we propose a boosting approach for building ensembles of QSVM models and assess performance improvement across multiple datasets. This approach is derived from the best ensemble building practices that worked well in traditional machine learning and thus should push the limits of quantum model performance even further. We find that in some cases, a single QSVM model with tuned hyperparameters is sufficient to simulate the data, while in others - an ensemble of QSVMs that are forced to do exploration of the feature space via proposed method is beneficial., Comment: 5 pages, 3 figures

The hot nine-component system HD 93206, which contains a gravitationally bounded eclipsing Ac1+Ac2 binary ($P=5.9987$~d) and a spectroscopic Aa1+Aa2 ($P=20.734$~d) binary can provide~important insights into the origin and evolution of massive stars. Using archival and new spectra, and a~rich collection of ground-based and space photometric observations, we carried out a detailed study of this object. We provide a much improved description of both short orbits and a good estimate of the mutual period of both binaries of about 14500~d (i.e. 40 years). For the first time, we detected weak lines of the fainter component of the 6.0~d eclipsing binary in the optical region of the spectrum, measured their radial velocities, and derived a mass ratio of $M_{\rm Ac2}/M_{\rm Ac1}=1.29$, which is the opposite of what was estimated from the International Ultraviolet explorer (IUE) spectra. We confirm that the eclipsing subsystem Ac is semi-detached and is therefore in a phase of large-scale mass transfer between its components. The Roche-lobe filling and spectroscopically brighter component Ac1 is the less massive of the two and is eclipsed in the secondary minimum. We show that the bulk of the \ha emission, so far believed to be associated with the eclipsing system, moves with the primary O9.7I component Aa1 of the 20.73~d spectroscopic binary. However, the weak emission in the higher Balmer lines seems to be associated with the accretion disc around component Ac2. We demonstrate that accurate masses and other basic physical properties including the distance of this unique system can be obtained but require a more sophisticated modelling. A~first step in this direction is presented in the accompanying Paper~II (Bro\v{z} et al.)., Comment: 20 pages, 12 Figures

The orbit of the outer satellite Alexhelios of (216) Kleopatra is already constrained by adaptive-optics astrometry, obtained with the VLT/SPHERE instrument. However, there is also a preceding occultation event in 1980 attributed to this satellite. Hereinafter, we try to link all observations, spanning 1980--2018. We find the nominal orbit exhibits an unexplained shift by $+60^\circ$ in the true longitude. Using both periodogram analysis and an $\ell = 10$ multipole model suitable for the motion of mutually interacting moons about the irregular body, we confirmed that it is not possible to adjust the respective osculating period $P_2$. Instead, we were forced to use a model with tidal dissipation (and increasing orbital periods) to explain the shift. We also analyzed light curves, spanning 1977--2021, and searched for the expected spin deceleration of Kleopatra. According to our best-fit model, the observed period rate is $\dot P_2 = (1.8\pm 0.1)\cdot 10^{-8}\,{\rm d}\,{\rm d}^{-1}$ and the corresponding time lag $\Delta t_2 = 42\,{\rm s}$ of tides, for the assumed value of the Love number $k_2 = 0.3$. It is the first detection of tidal evolution for moons orbiting 100-km asteroids. The corresponding dissipation factor $Q$ is comparable with other terrestrial bodies, albeit at a higher loading frequency $2|\omega-n|$. We also predict a secular evolution of the inner moon, $\dot P_1 = 5.0\cdot 10^{-8}$, as well as a spin deceleration of Kleopatra, $\dot P_0 = 1.9\cdot 10^{-12}$. In alternative models, with moons captured in the 3:2 mean-motion resonance or more massive moons, the respective values of $\Delta t_2$ are a factor of 2--3 lower. Future astrometric observations by direct imaging or occultations should allow to distinguish between these models, which is important for the internal structure and mechanical properties of (216) Kleopatra., Comment: accepted in A&A

Massive cores of the giant planets are thought to have formed in a gas disk by accretion of pebble-size particles whose accretional cross-section is enhanced by aerodynamic gas drag [1][2]. A commonly held view is that the terrestrial planet system formed later (30-200 Myr after the dispersal of the gas disk) by giant collisions of tens of roughly Mars-size protoplanets [3]. Here we propose, instead, that the terrestrial planets formed earlier by gas-driven convergent migration of protoplanets toward $\sim\!1\,{\rm au}$ (related ref. [4] invoked a different process to concentrate planetesimals). To investigate situations in which convergent migration occurs, we developed a radiation-hydrodynamic model with realistic opacities [5][6] to determine the thermal structure of the gas and pebble disks in the terrestrial planet zone. We find that protoplanets rapidly grow by mutual collisions and pebble accretion, and gain orbital eccentricities by gravitational scattering and the hot-trail effect [7][8]. The orbital structure of the terrestrial planet system is well reproduced in our simulations, including its tight mass concentration at 0.7-1 au and the small sizes of Mercury and Mars. The early-stage protosolar disk temperature exceeds 1500 K inside 0.4 au implying that Mercury grew in a highly reducing environment, next to the evaporation lines of iron and silicates, influencing Mercury's bulk composition [9]. In a late-stage cold gas disk, accretion of icy/hydrated pebbles would contribute to Earth's water budget., Comment: original submission; final vers. is available at NA website

Context. The recent estimates of the 3D shape of the M/Xe-type triple asteroid system (216) Kleopatra indicated a density of 5 g.cm$^{-3}$. Such a high density implies a high metal content and a low porosity which is not easy to reconcile with its peculiar dumbbell shape. Aims. Given the unprecedented angular resolution of the VLT/SPHERE/ZIMPOL camera, we aim to constrain the mass and the shape of Kleopatra with high accuracy, hence its density. Methods. We combined our new VLT/SPHERE observations of Kleopatra recorded in 2017 and 2018 with archival data, as well as lightcurve, occultation, and delay-Doppler images, to derive its 3D shape model using two different algorithms (ADAM, MPCD). Furthermore, an N-body dynamical model allowed us to retrieve the orbital elements of the two moons as explained in the accompanying paper. Results. The shape of Kleopatra is very close to an equilibrium dumbbell figure with two lobes and a thick neck. Its volume equivalent diameter (118.75$\pm$1.40) km and mass (2.97$\pm$0.32) 10$^{18}$ kg imply a bulk density of (3.38$\pm$0.50) g cm$^{-3}$. Such a low density for a supposedly metal-rich body indicates a substantial porosity within the primary. This porous structure along with its near-equilibrium shape is compatible with a formation scenario including a giant impact followed by reaccumulation. Kleopatra's current rotation period and dumbbell shape imply that it is in a critically rotating state. The low effective gravity along the equator of the body, together with the equatorial orbits of the moons and possibly rubble-pile structure, opens the possibility that the moons formed via mass shedding. Conclusions. Kleopatra is a puzzling multiple system due to the unique characteristics of the primary. It deserves particular attention in the future, with the Extremely Large Telescopes and possibly a dedicated space mission., Comment: Accepted for publication in Astronomy and Astrophysics

Asteroid families with ages younger than $1$ Myr offer an interesting possibility of studying the outcomes of asteroid disruptions that are little modified by subsequent evolutionary processes. We analyze a very young asteroid family associated with (18777) Hobson in the central part of the main belt. We aim at (i) understanding its peculiar size distribution, and (ii) setting an upper limit on the characteristic dispersal velocity at subkilometer sizes corresponding to the smallest visible Hobson members. We identified the Hobson family using an up-to-date asteroid catalog. A significant increase in the number of its known members allowed us to study their size distribution and compare it with computer simulations of catastrophic disruptions. Backward orbital integrations of the heliocentric orbits allowed us to confirm the previously suggested age of Hobson and helped to estimate limits of the ejection speed. The Hobson family has an unusual size distribution: two nearly equal-size bodies, followed by a population of smaller asteroids, whose distribution takes a characteristic power law. There are two possibilities to explain these data. Either a canonical impact onto a single parent body, requiring fine-tuned impact conditions that have not been studied so far, or an unconventional model for the parent object of the Hobson family, namely a binary with $\simeq 7-9$ km primary and a $\simeq 2.5$ km secondary. In the latter case, the primary was disrupted, leaving behind the largest remnant (18777) Hobson and a suite of subkilometer asteroids. The second largest asteroid, (57738) 2001 UZ160, is the nearly intact satellite of the parent binary. The excellent convergence of nominal orbits of Hobson members sets an upper limit of $\simeq (10-20)$ m s$^{-1}$ for the initial dispersal velocity of the known members, which is consistent with both formation models., Comment: 17 pages, 12 figures, 1 table, accepted for publication in Astronomy and Astrophysics

The effects of oxidative treatment of single-walled carbon nanotubes (SWCNTs) on the adhesion and proliferation of human osteoblasts (SAOS-2) were investigated. The surface properties of SWCNTs after oxygen plasma treatment were characterised by contact angle measurement, scanning electron microscopy and Raman spectroscopy. The immunofluorescent staining of vinculin, actin filaments and nuclei was used to probe cell adhesion and growth on SWCNT films. Our results show that adhesion and proliferation of human osteoblasts cultivated on SWCNT films indeed depends on the degree of an oxidative treatment. As an optimal procedure was found the treatment with oxygen plasma for 5 min. In the latter case the osteoblasts form a confluent layer with pronounced focal adhesions throughout the entire cell body. The optimal conditions compromise the effect of hydrophilic character of SWCNT films and the level of damage of SWCNT surface.

To interpret adaptive-optics observations of (216) Kleopatra, we need to describe an evolution of multiple moons, orbiting an extremely irregular body and including their mutual interactions. Such orbits are generally non-Keplerian and orbital elements are not constants. Consequently, we use a modified $N$-body integrator, which was significantly extended to include the multipole expansion of the gravitational field up to the order $\ell = 10$. Its convergence was verified against the `brute-force' algorithm. We computed the coefficients $C_{\ell m},S_{\!\ell m}$ for Kleopatra's shape, assuming a~constant bulk density. For solar-system applications, it was also necessary to implement a variable distance and geometry of observations. Our $\chi^2$ metric then accounts for the absolute astrometry, the relative astrometry (2nd moon with respect to 1st), angular velocities, and also silhouettes, constraining the pole orientation. This allowed us to derive the orbital elements of Kleopatra's two moons. Using both archival astrometric data and new VLT/SPHERE observations (ESO LP 199.C-0074), we were able to identify the true periods of the moons, $P_1 = (1.822359\pm0.004156)\,{\rm d}$, $P_2 = (2.745820\pm0.004820)\,{\rm d}$. They orbit very close to the 3:2 mean-motion resonance, but their osculating eccentricities are too small compared to other perturbations (multipole, mutual), so that regular librations of the critical argument are not present. The resulting mass of Kleopatra, $m_1 = (1.49\pm0.16)\cdot10^{-12}\,M_\odot$ or $2.97\cdot10^{18}\,{\rm kg}$, is significantly lower than previously thought. An implication explained in the accompanying paper (Marchis et al.) is that (216) Kleopatra is a critically rotating body., Comment: accepted in A&A

beta Lyr A is a complex binary system with an extensive observational dataset: light curves (from FUV to FIR), interferometric squared visibility, closure phase, triple product measurements, spectral-energy distribution (SED), high-resolution spectroscopy, differential visibility amplitude, and also differential phase. In particular, we use spectra from Ondrejov 2m telescope from 2013 to 2015, to measure the emission in Halpha, HeI, SiII, NeI, or CII lines, and differential interferometry by CHARA/VEGA from the 2013 campaign to measure wavelength-dependent sizes across Halpha and HeI 6678. This allows us to constrain not only optically thick objects (primary, secondary, accretion disk), but also optically thin objects (disk atmosphere, jets, shell). We extended our modelling tool Pyshellspec (based on Shellspec; a 1D LTE radiative transfer code) to include all new observables, to compute differential visibilities/phases, to perform a Doppler tomography, and to determine a joint chi^2 metric. After an optimisation of 38 free parameters, we derive a robust model of the beta Lyr A system. According to the model, the emission is formed in an extended atmosphere of the disk, two perpendicular jets expanding at ~700 km s^-1, and a symmetric shell with the radius ~70 R_S. The spectroscopy indicates a low abundance of carbon, 10^-2 of the solar value. We also quantify systematic differences between datasets and discuss alternative models, with higher resolution, additional asymmetries, or He-rich abundance., Comment: 19 pages, 31 figures

Asteroid pairs, two objects that are not gravitationally bound to one another, but share a common origin, have been discovered in the Main belt and Hungaria populations. Such pairs are of major interest, as the study of their evolution under a variety of dynamical influences can indicate the time since the pair was created. To date, no asteroid pairs have been found in the Jovian Trojans, despite the presence of several binaries and collisional families in the population. The search for pairs in the Jovian Trojan population is of particular interest, given the importance of the Trojans as tracers of planetary migration during the Solar system's youth. Here we report a discovery of the first pair, (258656) 2002~ES$_{76}$ and 2013~CC$_{41}$, in the Jovian Trojans. The two objects are approximately the same size and are located very close to the L4 Lagrange point. Using numerical integrations, we find that the pair is at least $360$~Myr old, though its age could be as high as several Gyrs. The existence of the (258656) 2002~ES$_{76}$--2013~CC$_{41}$ pair implies there could be many such pairs scattered through the Trojan population. Our preferred formation mechanism for the newly discovered pair is through the dissociation of an ancient binary system, triggered by a sub-catastrophic impact, but we can not rule out rotation fission of a single object driven by YORP torques. A by-product of our work is an up-to-date catalog of Jovian Trojan proper elements, which we have made available for further studies., Comment: 15 figs. Accepted for publication in MNRAS

The Euphrosyne asteroid family occupies a unique zone in orbital element space around 3.15 au and may be an important source of the low-albedo near-Earth objects. The parent body of this family may have been one of the planetesimals that delivered water and organic materials onto the growing terrestrial planets. We aim to characterize the compositional properties as well as the dynamical properties of the family. We performed a systematic study to characterize the physical properties of the Euphrosyne family members via low-resolution spectroscopy using the IRTF telescope. In addition, we performed smoothed-particle hydrodynamics (SPH) simulations and N-body simulations to investigate the collisional origin, determine a realistic velocity field, study the orbital evolution, and constrain the age of the Euphrosyne family. Our spectroscopy survey shows that the family members exhibit a tight taxonomic distribution, suggesting a homogeneous composition of the parent body. Our SPH simulations are consistent with the Euphrosyne family having formed via a reaccumulation process instead of a cratering event. Finally, our N-body simulations indicate that the age of the family is 280 Myr +180/-80 Myr, which is younger than a previous estimate., Comment: 10 pages, 13 figures, accepted to be published in A&A

Asteroid (31) Euphrosyne is one of the biggest objects in the asteroid main belt and the Euphrosyne family occupies a highly inclined region in the outer main belt and contains a remarkably large number of members, which is interpreted as an outcome of a disruptive cratering event. The goals of this adaptive-optics imaging study were threefold: to characterize the shape of Euphrosyne, to constrain its density, and to search for the large craters that may be associated with the family formation event. We obtained disk-resolved images of Euphrosyne using SPHERE/ZIMPOL at ESO's 8.2-m VLT as part of our large program (ID: 199.C-0074, PI: Vernazza). We reconstructed its 3D-shape using the adam shape modeling algorithm based on the SPHERE images and the available lightcurves of this asteroid. We analyzed the dynamics of the satellite with the genoid meta-heuristic algorithm. Finally, we studied the shape of Euphrosyne using hydrostatic equilibrium models. Our SPHERE observations show that Euphrosyne has a nearly spherical shape with the sphericity index of 0.9888 and its surface lacks large impact craters. Euphrosyne's diameter is 268+/-6 km, making it one of the top 10 largest main belt asteroids. We detected a satellite of Euphrosyne -- S/2019 (31) 1-- that is about 4 km across, on an circular orbit. The mass determined from the orbit of the satellite together with the volume computed from the shape model imply a density of 1665+/-242 kg/m^3, suggesting that Euphrosyne probably contain a large fraction of water ice in its interior. We find that the spherical shape of Euphrosyne is a result of the reaccumulation process following the impact, as in the case of (10) Hygiea. However, our shape analysis reveals that, contrary to Hygiea, the axis ratios of Euphrosyne significantly differ from the ones suggested by fluid hydrostatic equilibrium following reaccumulation., Comment: 12 pages, 6 figures, accepted to be published in A&A

Two modules of the AD detector have been studied with the test beam at the T10 facility at CERN. The AD detector is made of scintillator pads read out by wave-length shifters (WLS)coupled to clean fibres that carry the produced light to photo-multiplier tubes (PMTs). In ALICE the AD is used to trigger and study the physics of diffractive and ultra-peripheral collisions as well as for a variety of technical tasks like beam-gas background monitoring or as a luminometer. The position dependence of the modules' efficiency has been measured and the effect of hits on the WLS or PMTs has been evaluated. The charge deposited by pions and protons has been measured at different momenta of the test beam. The time resolution is determined as a function of the deposited charge. These results are important ingredients to better understand the AD detector, to benchmark the corresponding simulations, and very importantly they served as a baseline for a similar device, the Forward Diffractive Detector (FDD), being currently built and that will be in operation in ALICE during the LHC Runs 3 and 4., Comment: 12 pages, 9 figures

Analog quantum simulation is expected to be a significant application of near-term quantum devices. Verification of these devices without comparison to known simulation results will be an important task as the system size grows beyond the regime that can be simulated classically. We introduce a set of experimentally-motivated verification protocols for analog quantum simulators, discussing their sensitivity to a variety of error sources and their scalability to larger system sizes. We demonstrate these protocols experimentally using a two-qubit trapped-ion analog quantum simulator and numerically using models of up to five qubits.

The work presented in this paper aims to explore how, and to what extent, an adaptive robotic coach has the potential to provide extra motivation to adhere to long-term rehabilitation and help fill the coaching gap which occurs during repetitive solo practice in high performance sport. Adapting the behavior of a social robot to a specific user, using reinforcement learning (RL), could be a way of increasing adherence to an exercise routine in both domains. The requirements gathering phase is underway and is presented in this paper along with the rationale of using RL in this context., Comment: AI-HRI 2019

The study of photon-induced reactions in collisions of heavy nuclei at RHIC and the LHC has become an important direction of the research program of these facilities in recent years. In particular, the production of vector mesons in ultra-peripheral collisions (UPC) has been intensively studied. Owing to the intense photon fluxes, the two nuclei participating in such processes undergo electromagnetic dissociation producing neutrons at beam rapidities. Here, we introduce the $\textbf{n$\mathbf{_O^O}$n}$ (pronounced noon) Monte Carlo program, which generates events containing such neutrons. $\textbf{n$\mathbf{_O^O}$n}$ is a ROOT based program that can be interfaced with existing generators of vector meson production in UPC or with theoretical calculations of such photonuclear processes. $\textbf{n$\mathbf{_O^O}$n}$ can also be easily integrated with the simulation programs of the experiments at RHIC and the LHC., Comment: 25 pages, 14 figures

About 10% of the observed asteroids have rotational periods lower than P = 3 h and they seem to be relatively close to the spin barrier. Yet, the rotation has often been neglected in simulations of asteroid collisions. To determine the effect of rotation, we perform a large number of SPH/N-body impact simulations with rotating targets. We developed a new unified SPH/N-body code with self-gravity, suitable for simulations of both fragmentation phase and gravitational reaccumulation. The code has been verified against previous ones (Benz and Asphaug 1994), but we also tested new features, e.g. rotational stability, tensile stability, etc. Using the new code, we ran simulations with D_pb = 10 km and 100 km monolithic targets and compared synthetic asteroid families created by these impacts with families corresponding to non-rotating targets. The rotation affects mostly cratering events at oblique impact angles. The total mass ejected by these collision can be up to five times larger for rotating targets. We further compute the transfer of the angular momentum and determine conditions under which impacts accelerate or decelerate the target. While individual cratering collisions can cause both acceleration and deceleration, the deceleration prevails on average, collisions thus cause a systematic spin-down of asteroid population., Comment: Accepted for publication in A&A

Reliable determination of the basic physical properties of hot emission-line binaries with Roche-lobe filling secondaries is important for developing the theory of mass exchange in binaries. It is not easy, however, due to the presence of circumstellar matter. Here, we report the first detailed investigation of a new representative of this class of binaries, HD~81357, based on the analysis of spectra and photometry from several observatories. HD~81357 was found to be a double-lined spectroscopic binary and an ellipsoidal variable seen under an intermediate orbital inclination of $\sim(63\pm5)^\circ$, having an orbital period of 33\fd77445(41) and a~circular orbit. From an automated comparison of the observed and synthetic spectra, we estimate the component's effective temperatures to be 12930(540)~K and 4260(24)~K. The combined light-curve and orbital solutions, also constrained by a very accurate Gaia Data Release 2 parallax, give the following values of the basic physical properties: masses $3.36\pm0.15$ and $0.34\pm0.04$~\Mnom, radii $3.9\pm0.2$ and 13.97\pm0.05$~\Rnom, and a~mass ratio $10.0\pm0.5$. Evolutionary modelling of the system including the phase of mass transfer between the components indicated that HD~81357 is a~system observed in the final slow phase of the mass exchange after the mass-ratio reversal. Contrary to what has been seen for similar binaries like AU~Mon, no cyclic light variations were found on a~time scale an~order of magnitude longer than the orbital period. 243,1 15%, Comment: 16 pages, 9 figures; accepted for publication in Astronomy and Astrophysics

Experiential AI is proposed as a new research agenda in which artists and scientists come together to dispel the mystery of algorithms and make their mechanisms vividly apparent. It addresses the challenge of finding novel ways of opening up the field of artificial intelligence to greater transparency and collaboration between human and machine. The hypothesis is that art can mediate between computer code and human comprehension to overcome the limitations of explanations in and for AI systems. Artists can make the boundaries of systems visible and offer novel ways to make the reasoning of AI transparent and decipherable. Beyond this, artistic practice can explore new configurations of humans and algorithms, mapping the terrain of inter-agencies between people and machines. This helps to viscerally understand the complex causal chains in environments with AI components, including questions about what data to collect or who to collect it about, how the algorithms are chosen, commissioned and configured or how humans are conditioned by their participation in algorithmic processes., Comment: To appear in AI Matters 5(1): 25-31 (2019)

Robots are becoming a vital ingredient in society. Some of their daily tasks require dual-arm manipulation skills in the rapidly changing, dynamic and unpredictable real-world environments where they have to operate. Given the expertise of humans in conducting these activities, it is natural to study humans' motions to use the resulting knowledge in robotic control. With this in mind, this work leverages human knowledge to formulate a more general, real-time, and less task-specific framework for dual-arm manipulation. The proposed framework is evaluated on the iCub humanoid robot and several synthetic experiments, by conducting a dual-arm pick-and-place task of a parcel in the presence of unexpected obstacles. Results suggest the suitability of the method towards robust and generalisable dual-arm manipulation.

Asteroid (7) Iris is an ideal target for disk-resolved imaging owing to its brightness (V$\sim$7-8) and large angular size of 0.33 arcsec during its apparitions. Iris is believed to belong to the category of large unfragmented asteroids that avoided internal differentiation, implying that its current shape and topography may record the first few 100 Myr of the solar system's collisional evolution. We recovered information about the shape and surface topography of Iris from disk-resolved VLT/SPHERE/ZIMPOL images acquired in the frame of our ESO large program. We used the All-Data Asteroid Modeling (ADAM) shape reconstruction algorithm to model the 3D shape of Iris, using optical disk-integrated data and disk-resolved images from SPHERE as inputs. We analyzed the SPHERE images to infer the asteroid's global shape and the morphology of its main craters. We present the volume-equivalent diameter D$_{{\rm eq}}$=214$\pm$5 km, and bulk density $\rho$=2.7$\pm$0.3 g cm$^{-3}$ of Iris. Its shape appears to be consistent with that of an oblate spheroid with a large equatorial excavation. We identified eight putative surface features 20--40 km in diameter detected at several epochs, which we interpret as impact craters. Craters on Iris have depth-to-diameter ratios that are similar to those of analogous 10 km craters on Vesta. The bulk density of Iris is consistent with that of its meteoritic analog, namely LL ordinary chondrites. Considering the absence of a collisional family related to Iris and the number of large craters on its surface, we suggest that its equatorial depression may be the remnant of an ancient (at least 3 Gyr) impact. Iris's shape further opens the possibility that large planetesimals formed as almost perfect oblate spheroids. Finally, we attribute the difference in crater morphology between Iris and Vesta to their different surface gravities., Comment: Accepted for publication in Astronomy and Astrophysics

We present radiation hydrodynamic simulations in which binary planets form by close encounters in a system of several super-Earth embryos. The embryos are embedded in a protoplanetary disk consisting of gas and pebbles and evolve in a region where the disk structure supports convergent migration due to Type I torques. As the embryos accrete pebbles, they become heated and thus affected by the thermal torque (Ben\'{i}tez-Llambay et al. 2015) and the hot-trail effect (Chrenko et al. 2017) which excites orbital eccentricities. Motivated by findings of Eklund & Masset (2017), we assume the hot-trail effect operates also vertically and reduces the efficiency of inclination damping. Non-zero inclinations allow the embryos to become closely packed and also vertically stirred within the convergence zone. Subsequently, close encounters of two embryos assisted by the disk gravity can form transient binary planets which quickly dissolve. Binary planets with a longer lifetime $\sim$$10^{4}$ yr form in 3-body interactions of a transient pair with one of the remaining embryos. The separation of binary components generally decreases in subsequent encounters and due to pebble accretion until the binary merges, forming a giant planet core. We provide an order-of-magnitude estimate of the expected occurrence rate of binary planets, yielding one binary planet per $\simeq$$2$--$5\times10^{4}$ planetary systems. Therefore, although rare, the binary planets may exist in exoplanetary systems and they should be systematically searched for., Comment: Accepted for publication in ApJ, 18 pages, 10 figures

In order to fully understand the shapes of asteroids families in the 3-dimensional space of the proper elements $(a_{\rm p}, e_{\rm p}, \sin I_{\rm p})$ it is necessary to compare observed asteroids with N-body simulations. To this point, we describe a rigorous yet simple method which allows for a selection of the observed asteroids, assures the same size-frequency distribution of synthetic asteroids, accounts for a background population, and computes a $\chi^2$ metric. We study the Eos family as an example, and we are able to fully explain its non-isotropic features, including the distribution of pole latitudes $\beta$. We confirm its age $t = (1.3\pm0.3)\,{\rm Gyr}$; while this value still scales with the bulk density, it is verified by a Monte-Carlo collisional model. The method can be applied to other populous families (Flora, Eunomia, Hygiea , Koronis, Themis, Vesta, etc.)., Comment: 9 pages, 12 figures

Protoplanets of Super-Earth sizes may get trapped in convergence zones for planetary migration and form gas giants there. These growing planets undergo accretion heating, which triggers a hot-trail effect that can reverse migration directions, increase eccentricities and prevent resonant captures (Chrenko et al. 2017). We study populations of embryos accreting pebbles using Fargo-Thorin 2D hydrocode. We find that embryos in a disk with high surface density ($\Sigma_0 = 990\,{\rm g}\,{\rm cm}^{-2}$) undergo `unsuccessful' two-body encounters which do not lead to a merger. Only when a 3rd protoplanet arrives to the convergence zone, three-body encounters lead to mergers. For a low-viscosity disk ($\nu = 5\times10^{13}\,{\rm cm}^2\,{\rm s}^{-1}$) a massive coorbital is a possible outcome, for which a pebble isolation develops and the coorbital is stabilised. For more massive protoplanets ($5\,M_\oplus$), the convergence radius is located further out, in the ice-giant zone. After a series of encounters, there is an evolution driven by a dynamical torque of a tadpole region, which is systematically repeated several times, until the coorbital configuration is disrupted and planets merge. This may be a pathway how to solve the problem that coorbitals often form in simulations but they are not observed in nature. In contrast, the joint evolution of 120 low-mass protoplanets ($0.1\,M_\oplus$) reveals completely different dynamics. The evolution is no longer smooth, but rather a random walk. This is because the spiral arms, developed in the gas disk due to Lindblad resonances, overlap with each other and affect not only a single protoplanet but several in the surroundings. Our hydrodynamical simulations may have important implications for N-body simulations of planetary migration that use simplified torque prescriptions and are thus unable to capture protoplanet dynamics in its full glory., Comment: 15 pages, 25 figures, Astronomy & Astrophysics, accepted