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Combining archival photometric observations from multiple large-area surveys spanning the past 17 years, we detect long-term variability in the light curves of ZTF J032833.52−121945.27 (ZTF J0328−1219), ZTF J092311.41+423634.16 (ZTF J0923+4236), and WD 1145+017, all known to exhibit transits from planetary debris. ZTF J0328−1219 showed an overall fading in brightness from 2011 through to 2015, with a maximum dimming of ≃0.3 mag, and still remains ≃0.1 mag fainter compared to 2006. We complement the analysis of the long-term behaviour of these systems with high-speed photometry. In the case of ZTF J0923+4236 and WD 1145+017, the time-series photometry exhibits vast variations in the level of transit activity, both in terms of numbers of transits, as well as their shapes and depths, and these variations correlate with the overall brightness of the systems. Inspecting the current known sample of white dwarfs with transiting debris, we estimate that similar photometric signatures may be detectable in one in a few hundred of all white dwarfs. Accounting for the highly aligned geometry required to detect transits, our estimates imply that a substantial fraction of all white dwarfs exhibiting photospheric metal pollution from accreted debris host close-in planetesimals that are currently undergoing disintegration. [ABSTRACT FROM AUTHOR]

The article titled "Sky Notes: 2024 April & May" provides information for amateur astronomers in the UK about observing opportunities during the spring months. While the planetary scene is not very exciting during this time, there are still chances to observe the deep sky, including the local supercluster of galaxies in Ursa Major, Canes Venatici, and Coma Berenices. The article also highlights the Coma-Virgo Cluster, which is rich in galaxies and can be explored by sweeping southeast from Denebola towards epsilon Virginis. The article also mentions upcoming astronomical events like a total solar eclipse and meteor showers. Another text provides information about the galaxy Messier 87, which contains a supermassive black hole at its center. The galaxy is spherical and consists of older stars, with a diameter of 130,000 light-years and an estimated mass of 2.7 billion solar masses. The text also mentions other galaxies and celestial objects in the same area of the sky that can be observed by amateur astronomers. [Extracted from the article]

The surface of Phobos is an intriguing subject of research for many scientists. This is associated, among other things, with the fact that it is perceived as a potential launch site for future human Mars exploration. Additionally, measurements conducted on its surface would not only deepen our knowledge about Phobos but also provide insights into geochemical processes occurring on similar small bodies in the Solar System. Therefore, understanding the physical–mechanical properties of regolith is a crucial aspect of planetary exploration. These properties are key factors needed for both planning safe landings and establishing future bases on celestial bodies. In this paper, information is compiled regarding hypotheses about its origin, the probable composition of Phobos' surface (spectral properties and HiRISE data), as well as its morphology. The article also presents the process of regolith formation covering Phobos' surface and its presumed physical properties. It has been established that the estimated bulk density of Phobos, compared to the densities of other asteroids and meteorites, is most similar to C-type asteroids. It was also found that C-type asteroids, in terms of total porosity, best reflect Phobos. However, determining the surface composition of Phobos and its detailed physical properties requires additional information, which could be obtained through in situ studies or sample return missions. [ABSTRACT FROM AUTHOR]

The minimal sizes of impactors that produced asteroid families were calculated, and their maximal sizes, i.e. the size that corresponds to head-on collisions, were estimated. We used data for 16 large families and the physical parameters of some members of these families available in NASA's JPL updated in 2022. We found that the typical minimal sizes of family-forming impactors were of the order of one-tenth the size of the parent bodies (PBs). The Themis family, for which the ratio of the radii r imp/ R PB = 0.08 and the mass loss is as large as 0.55, presents an example. The families of Juno and Euphrosyne, with the impactor to PB size ratio of an order of 0.01, are rather exceptional. The PBs of Juno and Euphrosyne families lost only 0.0014 and 0.0061 of their mass, respectively. It was found that the double structure of the Vesta family could have originated from two impacts by the bodies with radii as small as about 4 km, at least. [ABSTRACT FROM AUTHOR]

C/2019 Y4 (ATLAS) is an Oort cloud comet with an orbital period of ∼5895 yr. Starting in 2020 March, its nucleus underwent disintegration. In order to investigate the gas and dust properties of C/2019 Y4 (ATLAS) during its disintegration, we obtained long-slit spectra at 3600–8700 Å and BVRI multiband images with the Xinglong 2.16 m Telescope in 2020 April. Our observations revealed that C/2019 Y4 (ATLAS) exhibited strong emission bands of CN, C2, C3, and NH2, which are superimposed on a dust-scattering continuum, typical of cometary spectra in the optical. The production rates of CN, C2, and C3 derived using the Haser model and the corresponding C2/CN and C3/CN ratios suggest that C/2019 Y4 (ATLAS) is a "typical" Oort cloud comet under the A'Hearn classification, although it appears less dusty, as revealed by the Af ρ quantities. Its dust-scattering reflectivity is slightly red, with a gradient of ∼5% per 103Å. We model the reflectivity gradient in terms of porous dust and find that the red color is accounted for by porous dust. [ABSTRACT FROM AUTHOR]

Euclid, a space telescope, is facing issues with ice accumulation on its optics, affecting its vision. The mission teams are testing a new procedure to de-ice the optics and find a long-term solution. A study has found that thermal stresses break up large meteoroids near Earth, observed when multiple meteors are detected in a short period. A star from the second generation in the Large Magellanic Cloud has been discovered, shedding light on element formation in other galaxies. The impact of NASA's DART mission on the asteroid Dimorphos changed its motion and shape, suggesting it is a loosely packed object. [Extracted from the article]

For fast-rotating asteroids, observed light curves could be very different from real light curves due to long exposure time. We present an improved observed light-curve model that accounts for long exposure time often encountered in observations of fast-rotating asteroids. By integrating brightness over time, we derive a more accurate observed light-curve model, allowing for better shape and spin state inversion results. Our analysis demonstrates that the fast-rotating model is more suitable for spin state inversion with longer exposure time, while the Kaasalainen model suffices for shorter exposure time. For spin state and shape inversion, exposure times of approximately 0.4 P and 0.2 P represent critical thresholds, respectively, beyond which the fast-rotating model exhibits superior performance. Notably, scattering parameters have minimal impact on the shape inversion results. These findings contribute valuable insights to the determination of shape and spin states for fast-rotating asteroids, shedding light on the challenges posed by long exposure time in such investigations. [ABSTRACT FROM AUTHOR]

This work presents novel findings that broaden our understanding of the amount of water that can be transported to the Earth. The key innovation lies in the combined usage of smoothed particle hydrodynamics (SPH) and N -body codes to assess the role of collision fragments in water delivery. We also present a method for generating initial conditions that enables the projectile to impact at the designated location on the target's surface with the specified velocity. The primary objective of this study is to simulate giant collisions between two Ceres-sized bodies by SPH near the ν6 secular resonance and follow the evolution of the ejected debris by numerical N -body code. With our method 6 different initial conditions for the collision were determined, and the corresponding impacts were simulated by SPH. Examining the orbital evolution of the debris ejected after collisions, we measured the amount of water delivered to the Earth, which is broadly 0.001 ocean equivalents of water, except in one case where one large body transported 7 per cent oceans of water to the planet. Based on this and taking into account the frequency of collisions, the amount of delivered water varies between 1.2 and 8.3 ocean's worth of water, depending on the primordial disc mass. According to our results, the prevailing external pollution model effectively accounts for the assumed water content on the Earth, whether it's estimated at 1 or 10 ocean's worth of water. [ABSTRACT FROM AUTHOR]

This work deals with a possible ultraviolet and infrared luminescence of the solid substance of the near-Earth objects. In particular, features of the phenomena of photoluminescence and cathodoluminescence of substance of these objects are considered. It is shown that ultraviolet and infrared luminescence of these objects can be revealed by orbital-based instruments. It is demonstrated that detectability of luminescence of near-Earth objects opens up the possibilities for determination of the physical–chemical properties of their solid substance and finding of the dark small low-albedo bodies, which could approach dangerously closer to the Earth. Equations for calculation of luminescence intensity of these objects are proposed. Data on the luminescence of the corresponding minerals and the numerical values of the yields of luminescence and albedo, as the conditions for the detectability of the luminescence of near-Earth objects are presented as well. [ABSTRACT FROM AUTHOR]

Objective: In the framework of the Cometary Physics Laboratory (CoPhyLab) and its sublimation experiments of cometary surface analogues under simulated space conditions, we characterize the properties of intimate mixtures of juniper charcoal and SiO2 chosen as a dust analogue (Lethuillier et al. 2022). We present the details of these investigations for the spectrophotometric properties of the samples. Methods: We measured these properties using a hyperspectral imager and a radio-goniometer. From the samples' spectra, we evaluated reflectance ratios and spectral slopes. From the measured phase curves, we inverted a photometric model for all samples. Complementary characterizations were obtained using a pycnometer, a scanning electron microscope and an organic elemental analyser. Results: We report the first values for the apparent porosity, elemental composition, and VIS-NIR spectrophotometric properties for juniper charcoal, as well as for intimate mixtures of this charcoal with the SiO2. We find that the juniper charcoal drives the spectrophotometric properties of the intimate mixtures and that its strong absorbance is consistent with its elemental composition. We find that SiO2 particles form large and compact agglomerates in every mixture imaged with the electron microscope, and its spectrophotometric properties are affected by such features and their particle-size distribution. We compare our results to the current literature on comets and other small Solar system bodies and find that most of the characterized properties of the dust analogue are comparable to some extent with the spacecraft-visited cometary nuclei, as well as to Centaurs, Trojans, and the bluest TNOs. [ABSTRACT FROM AUTHOR]

We apply the Hierarchical Clustering method (HCM) and Selective Backward Integration method (BIM) to search for associated families and young families for all main-belt active asteroids (MBAAs) known to date. We find four newly candidate sub-groups of known families, which include the candidate Brueghel family associated with 176P/LINEAR, the candidate 324P group associated with 324P/La Sagra, the candidate G1 group associated with P/2016 G1, and the candidate Tutenchamun family associated with (62412) 2000 SY178. Additionally, we identify three entirely new candidate families, the Interamnia family associated with P/2021 A5, the candidate 457P group associated with 457P/Lemmon-PANSTARRS, and the candidate Scheila family associated with (596) Scheila. We also reveal two newly identified family associations with known families between 259P/Garradd and the Adeona family, P/2019 A4 and the Jones family. All main-belt comets (MBCs) are likely associated with young and primitive families. Some unstable MBCs, which cannot be identified using HCM, may still originate from young and primitive families. However, due to dynamic diffusion, they cannot be conclusively linked to current families. Impact-disrupted asteroids could be linked with young families and they may change their original spectrum under the impact activity. Rotational fission of young and primitive asteroids might be a useful mechanism for facilitating the exposure of subsurface ice, and therefore triggering sublimation-driven activity. Rapid rotation and sublimation activity mechanisms are likely coupled. Therefore, further research should be made on such fast rotational asteroids that are located in primitive families. [ABSTRACT FROM AUTHOR]

The impact of the Double Asteroid Redirection Test (DART) spacecraft with Dimorphos allows us to study asteroid collision physics, including momentum transfer, the ejecta properties, and the visibility of such events in the Solar system. We report observations of the DART impact in the ultraviolet (UV), visible light, and near-infrared (IR) wavelengths. The observations support the existence of at least two separate components of the ejecta: a fast and a slow component. The fast-ejecta component is composed of a gaseous phase, moving at about 1.6 km s−1 with a mass of ≲104 kg. The fast ejecta is detected in the UV and visible light, but not in the near-IR z -band observations. Fitting a simplified optical thickness model to these observations allows us to constrain some of the properties of the fast ejecta, including its scattering efficiency and the opacity of the gas. The slow ejecta component is moving at typical velocities of up to about 10 m s−1. It is composed of micrometer-size particles, that have a scattering efficiency, at the direction of the observer, of the order of 10−3 and a total mass of ∼106 kg. The larger particles in the slow ejecta, whose size is bound to be in the range between ∼1 mm and ∼1 m, likely have a scattering efficiency larger than that of the pre-impact Didymos system. [ABSTRACT FROM AUTHOR]

Submicron debris released in interplanetary collisions gets charged in the solar wind and generates disturbances to the magnetic field environment. The unique magnetic field disturbances, named interplanetary field enhancements (IFEs) are recorded by many spacecraft. In this study, we have developed a novel model to trace the IFEs to their origins. By employing this model, we can pinout regions with highly collision frequencies, thereby identifying regions of intense collisional activity. The model can help constrain interplanetary magnetic disturbances and our results can be used to guide part of the interplanetary-object survey. [ABSTRACT FROM AUTHOR]

On 2023 December 12, the star α Orionis will be occulted by asteroid (319) Leona. This represents an extraordinary and unique opportunity to analyse the brightness distribution of Betelgeuse's photosphere with extreme angular resolution by studying light curves from different points on Earth and at different wavelengths. Here we present observations of another occultation by asteroid Leona, on 2023 September 13, whose goal was to determine Leona's projected shape and size in preparation for the December 12th event and its interpretation. The occultation campaign was highly successful with 25 positive detections from 17 different sites and a near miss. The effective diameter in projected area derived from the positive detections was 66 ± 2 km using an elliptical fit to the instantaneous limb. The body is highly elongated, with dimensions of 79.6 ± 2.2 km × 54.8 ± 1.3 km in its long and short axis, respectively, at occultation time. This result, in combination with dense time series photometry of Leona that we recently obtained, together with archival sparse photometry, allowed us to predict the angular size of the asteroid for the Betelgeuse event and to simulate the expected brightness change. Also, an accurate position coming from the occultation is provided, to improve the orbit of Leona. [ABSTRACT FROM AUTHOR]

Charles Smallwood (1812-1873) is well known as an early Canadian meteorologist and possessor of a very valuable "Fraunhofer" refractor, 17 cm (7 inches) in diameter and 3.35 m (11 feet) in length. Here, for the first time since Smallwood's time, some more details are provided about the telescope and the observations he made with it in the 1850s including planets and their satellites, minor planets, double stars, clusters and nebulae in the Messier catalogue. [ABSTRACT FROM AUTHOR]

We analyse the role of the general relativity (GR) on the nodal librations of test particles located at the Habitable Zone (HZ) around a solar-mass star, which evolve under the influence of an eccentric planetary-mass perturber with a semimajor axis of 0.1 au. Based on a secular Hamiltonian up to quadrupole level, we derive analytical criteria that define the nodal libration region of an HZ particle as a function of its eccentricity e 2 and inclination i 2, and the mass m 1 and the eccentricity e 1 of the perturber. We show that an HZ particle can experience nodal librations with orbital flips or purely retrograde orbits for any m 1 and e 1 by adopting a suitable combination of e 2 and i 2. For m 1 < 0.84 MJup, the greater the m 1 value, the smaller the e 2 value above which nodal librations are possible for a given e 1. For m 1 > 0.84 MJup, an HZ test particle can undergo nodal librations for any e 2 and appropriate values of e 1 and i 2. The same correlation between m 1 and e 2 is obtained for nodal librations with orbital flips, but a mass limit for m 1 of 1.68 MJup is required in this case. Moreover, the more massive the inner perturber, the greater the nodal libration region associated with orbital flips in the (e 1, i 2) plane for a given value of e 2. Finally, we find good agreements between the analytical criteria and results from N -body simulations for values of m 1 ranging from Saturn-like planets to super-Jupiters. [ABSTRACT FROM AUTHOR]

We present 24 new dense light curves of the near-Earth asteroids (3103) Eger, (161989) Cacus, (2100) Ra-Shalom, and (12711) Tukmit, obtained with the Instituto Astrofísico Canarias 80 and Telescopio Abierto Remoto 2 telescopes at the Teide Observatory (Tenerife, Spain) during 2021 and 2022, in the framework of projects visible NEAs observations survey and NEO Rapid Observation, Characterization and Key Simulations. The shape models and rotation state parameters (P , λ, β) were computed by applying the light curve inversion method to the new data altogether with the archival data. For (3013) Eger and (161989) Cacus, our shape models and rotation state parameters agree with previous works, though they have smaller uncertainties. For (2100) Ra-Shalom, our results also agree with previous studies. Still, we find that a Yarkovsky–O'Keefe–Radzievskii–Paddack acceleration of υ = (0.223 ± 0.237) × 10−8 rad d−2 slightly improves the fit of the light curves, suggesting that (2100) Ra-Shalom could be affected by this acceleration. We also present for the first time a shape model for (12711) Tukmit, along with its rotation state parameters (P  = 3.484900 ± 0.000031 h, λ = 27° ± 8°, β = 9° ± 15°). [ABSTRACT FROM AUTHOR]

While proper orbital elements are currently available for more than 1 million asteroids, taxonomical information is still lagging behind. Surveys like SDSS-MOC4 provided preliminary information for more than 100 000 objects, but many asteroids still lack even a basic taxonomy. In this study, we use Dark Energy Survey (DES) data to provide new information on asteroid physical properties. By cross-correlating the new DES data base with other data bases, we investigate how asteroid taxonomy is reflected in DES data. While the resolution of DES data is not sufficient to distinguish between different asteroid taxonomies within the complexes, except for V-type objects, it can provide information on whether an asteroid belongs to the C- or S-complex. Here, machine learning methods optimized through the use of genetic algorithms were used to predict the labels of more than 68 000 asteroids with no prior taxonomic information. Using a high-quality, limited set of asteroids with data on gri slopes and i − z colours, we detected 409 new possible V-type asteroids. Their orbital distribution is highly consistent with that of other known V-type objects. [ABSTRACT FROM AUTHOR]

The Centaur (60558) Echeclus was discovered on 2000 March 03, orbiting between the orbits of Jupiter and Uranus. After exhibiting frequent outbursts, it also received a comet designation, 174P. If the ejected material can be a source of debris to form additional structures, studying the surroundings of an active body like Echeclus can provide clues about the formation scenarios of rings, jets, or dusty shells around small bodies. Stellar occultation is a handy technique for this kind of investigation, as it can, from Earth-based observations, detect small structures with low opacity around these objects. Stellar occultation by Echeclus was predicted and observed in 2019, 2020, and 2021. We obtain upper detection limits of rings with widths larger than 0.5 km and optical depth of τ = 0.02. These values are smaller than those of Chariklo's main ring; in other words, a Chariklo-like ring would have been detected. The occultation observed in 2020 provided two positive chords used to derive the triaxial dimensions of Echeclus based on a 3D model and pole orientation available in the literature. We obtained a  = 37.0 ± 0.6 km, b  = 28.4 ± 0.5 km, and c  = 24.9 ± 0.4 km, resulting in an area-equivalent radius of 30.0 ± 0.5 km. Using the projected limb at the occultation epoch and the available absolute magnitude (⁠|$\rm {H}_{\rm {v}} = 9.971 \pm 0.031$|⁠), we calculate an albedo of p v = 0.050 ± 0.003. Constraints on the object's density and internal friction are also proposed. [ABSTRACT FROM AUTHOR]

The rotational properties of ∼10-m-scale asteroids are poorly understood with only a few measurements. Additionally, collisions or thermal recoil can spin their rotations to periods less than a few seconds obfuscating their study due to the observational cadence imposed by the long read-out times of charge-coupled device imagers. We present a method to measure the rotation periods of 10-m-scale asteroids using the target of opportunity capability of the Canada–France–Hawaii Telescope (CFHT) and its MegaCam imager by intentionally streaking their detections in single exposures when they are at their brightest. Periodic changes in brightness as small as ∼0.05 mag along the streak can be measured as short as a few seconds. Additionally, the streak photometry is taken in multiple g, r , and i filter exposures enabling the measurement of asteroid colours. The streak photometry method was tested on CFHT observations of three 10-m-scale asteroids, 2016 GE1, 2016 CG18, and 2016 EV84. Our three targets are among the smallest known asteroids with measured rotation periods/colours having some of the shortest known rotation periods. We compare our rotation period and taxonomic results with independent data from the literature and discuss applications of the method to future small asteroid observations. [ABSTRACT FROM AUTHOR]

Fireball monitoring network is the main equipment for monitoring impact from small-size near-Earth objects (NEOs), and determining meteorite fall locations. In this paper, a monitoring system using a multi-station distributed all-sky video camera network is proposed, and a regional prototype system has been constructed in Jiangsu and surrounding areas. The main processes of fireball monitoring were implemented, including network control, video capture, data processing, trajectory determination, and orbit calculation. After running for 1 yr, the results show that the limiting apparent magnitude - 1.0 for meteors in the video, and the absolute magnitude exhaustive detection regime can reach around - 2.5. The flux of fireballs is found to be 2.68 × 10 − 7 km − 2 · h − 1. The percentages of streams and sporadic meteors are 46% and 54%, respectively, and the fraction of cometary orbits equals 72.9%, while for asteroidal-type it is 27.1%. The statistical results are close to those of the international meteor monitoring networks, which verified the monitoring capability of the network system in practical operation. [ABSTRACT FROM AUTHOR]

In this paper, we perform a dynamical study of the population of objects in the unstable quasi-Hilda region. The aim of this work is to make an update of the population of quasi-Hilda comets (QHCs) that have recently arrived from the Centaurs region. To achieve our goal, we have applied a dynamical criteria to constrain the unstable quasi-Hilda region that allowed us to select 828 potential candidates. The orbital data of the potential candidates were taken from the ASTORB data base and we apply backward integration to search by those that have recently arrived from the outer regions of the Solar system. Then we studied the dynamical evolution of the candidates from a statistical point of view by calculating the time-averaged distribution of a number of clones of each candidate as a function of aphelion and perihelion distances. We found that 47 objects could have been recently injected into the inner Solar system from the Centaur or transneptunian regions. These objects may have preserved volatile material and are candidates to exhibit cometary activity. [ABSTRACT FROM AUTHOR]

Contact binary asteroids are ubiquitous in the solar system: the Kuiper belt, main belt, and near-Earth populations all house these complex aggregates. Although contact binaries account for up to 30% of small bodies in the solar system, the formation of one has yet to be observed. We present a preliminary mission design to create a contact binary asteroid and observe its formation using a binary NEO system, a kinetic impactor, and an observer spacecraft. Not only does this mission address an important gap in planetary science, it also serves the planetary defense community: it will further demonstrate planetary defense technology to provide unique observation opportunities. A binary system offers a convenient natural laboratory for this mission, as the ability to form a contact binary using a kinetic impactor depends greatly on the size of the target and the proximity to its parent body. From among all known binary near-Earth objects, binary asteroid system (350751) 2002 AW was chosen for this case study. A spacecraft can achieve rendezvous with this system from low-Earth orbit with a cheap total Δ V ≈ 4.3 km/s. A pair of spacecraft launch on the same launch vehicle and separate before asteroid impact. The two spacecraft are (1) an impactor that has been adapted from the DART spacecraft and (2) an observer spacecraft that will rendezvous with the binary system and observe the creation of the contact binary. The spacecraft impact must be designed such that it redirects the secondary into a collision course with the primary while not catastrophically disrupting the target asteroid. Impact parameters such as angle of impact, catastrophic disruption limit, and the β factor have been considered. Among other design decisions, we present our target-selection methodology, launch-vehicle considerations, and launch opportunities. • Details mission design to create a contact binary. • Demonstrates utility of planetary defense technology to yield scientific results. • Specifies target selection process for mission. [ABSTRACT FROM AUTHOR]

Long-period comets are planetesimal remnants constraining the environment and volatiles of the protoplanetary disc. We report the discovery of hyperbolic long-period comet C/2022 E3 Zwicky Transient Facility (ZTF), which has a perihelion ∼1.11 au, an eccentricity ≳1 and an inclination ∼109°, from images taken with the Palomar 48-inch telescope during morning twilight on 2022 March 2. Additionally, we report the characterization of C/2022 E3 (ZTF) from observations taken with the Palomar 200-inch, the Palomar 60-inch, and the NASA Infrared Telescope Facility in early 2023 February to 2023 March when the comet passed within ∼0.28 au of the Earth and reached a visible magnitude of ∼5. We measure g – r = 0.70 ± 0.01, r – i = 0.20 ± 0.01, i – z = 0.06 ± 0.01, z – J = 0.90 ± 0.01, J – H = 0.38 ± 0.01, and H – K = 0.15 ± 0.01 colours for the comet from observations. We measure the A(0°)fρ (0.8 μm) in a 6500 km radius from the nucleus of 1483 ± 40 cm, and CN, C3, and C2 production of 5.43 ± 0.11 × 1025, 2.01 ± 0.04 × 1024, and 3.08 ± 0.5 × 1025 mol s−1, similar to other long-period comets. We additionally observe the appearance of jet-like structures at a scale of ∼4000 km in wide-field g -band images, which may be caused by the presence of CN gas in the near-nucleus coma. [ABSTRACT FROM AUTHOR]

Although the present-day orbital distribution of minor bodies that go around the Sun between the orbit of Neptune and the Kuiper Cliff is well understood, past ∼50 au from the Sun, our vision gets blurred as objects become fainter and fainter and their orbital periods span several centuries. Deep imaging using the largest telescopes can overcome the first issue but the problems derived from the second one are better addressed using data analysis techniques. Here, we make use of the heliocentric range and range-rate of the known Kuiper belt objects and their uncertainties to identify structures in orbital parameter space beyond the Kuiper Cliff. The distribution in heliocentric range there closely resembles that of the outer main asteroid belt with a gap at ∼70 au that may signal the existence of a dynamical analogue of the Jupiter family comets. Outliers in the distribution of mutual nodal distances suggest that a massive perturber is present beyond the heliopause. [ABSTRACT FROM AUTHOR]

Small Solar system bodies serve as pristine records that have been minimally altered since their formation. Their observations provide valuable information regarding the formation and evolution of our Solar system. Interstellar objects can also provide insight on the formation of exoplanetary systems and planetary system evolution as a whole. In this work, we present the application of our framework to search for small Solar system bodies in exoplanet transit survey data collected by the Antarctic Search for Transiting ExoPlanets (ASTEP) project. We analysed data collected during the Austral winter of 2021 by the ASTEP 400 telescope located at the Concordia Station, at Dome C, Antarctica. We identified 20 known objects from dynamical classes ranging from Inner Main-belt asteroids to one comet. Our search recovered known objects down to a magnitude of V  = 20.4 mag, with a retrieval rate of ∼80 per cent for objects with V ≤ 20 mag. Future work will apply the pipeline to archival ASTEP data that observed fields for periods of longer than a few hours to treat them as deep-drilling data sets and reach fainter limiting magnitudes for slow-moving objects, on the order of V ≈ 23–24 mag. [ABSTRACT FROM AUTHOR]

The paper discusses priority scientific tasks related to the study of small bodies in the Solar System, identifies the most promising objects for investigation from a spacecraft on a flyby trajectory and the sample return mission, and develops proposals for the preliminary composition of scientific instruments for remote asteroid research methods. A long-term and phased Russian scientific program for studying small Solar System bodies using spacecraft with electric propulsion has been proposed. The project is designed in such a way as to explore the largest number of scientifically interesting asteroids using a smaller number of spacecraft. A design concept for a small spacecraft to investigate near-Earth asteroids on a flyby trajectory and a main spacecraft for studying metallic asteroids in the Main Belt and sample sample return has been developed. A ballistic analysis of the flyby of five near-Earth asteroids and three metallic asteroids in the Main Belt is presented, as well as a ballistic analysis of the sample return mission from a Main Belt asteroid. The option of sample return using the nuclear tug Zevs is also considered. [ABSTRACT FROM AUTHOR]

The study of near-Earth objects (NEOs) allow us to obtain information on the Solar system smallest bodies due to their closeness to Earth. In this work, we present the results of visible spectroscopic observations of 43 small and newly discovered NEOs, obtained during eighteen observing runs between October 2020 and December 2021, using the Goodman High Throughput Spectrograph at the 4.1-m Southern Astrophysical Research telescope (Cerro Pachón, Chile). We found a taxonomic distribution dominated by S-type asteroids but with an overabundance of A- and D-types. This result is in agreement with recent works on NEOs' characterization and has implications for possible differences in the taxonomic distribution of 'large' and 'small' objects and emphasizes the idea of a non-homogeneous NEO population. [ABSTRACT FROM AUTHOR]

Small bodies in the Solar System are appealing targets for scientific and technological space missions, owing to their diversity in intrinsic and extrinsic properties, besides orbit and other factors. Missions to small bodies pass through the critical onboard object detection phase, where the body's light becomes visible to the spacecraft camera. The relative line-of-sight to the object is acquired and processed to feed relative guidance and navigation algorithms, therefore steering the spacecraft trajectory towards the target. This work assesses the distance of detection for each small body in the Solar System considering the target radiometric properties, three typical spacecraft camera setups, and the relative observation geometry by virtue of a radiometric model. Several uncertainties and noises are considered in the modelling of the detection process. The detection distances for each known small body are determined for small-, medium-, and large-class spacecraft. This proves useful for early mission design phases, where a waypoint for detection needs to be determined, allowing the shift from an absolute to a relative guidance and navigation phase. The work produces an extensive dataset that is freely accessible and useful for teams working on the design phases of space missions. [ABSTRACT FROM AUTHOR]

We present a physical model and spin-state analysis of the potentially hazardous asteroid (23187) 2000 PN9. As part of a long-term campaign to make direct detections of the Yarkovsky–O'Keefe–Radzievskii–Paddack (YORP) effect, we collected optical light curves of the asteroid between 2006 and 2020. These observations were combined with planetary radar data to develop a detailed shape model, which was used to search for YORP acceleration. We report that 2000 PN9 is a relatively large top-shaped body with a sidereal rotation period of 2.53216 ± 0.00015 h. Although we find no evidence for rotational acceleration, YORP torques smaller than |$\sim 10^{-8}\, \rm rad\,{d}^{-2}$| cannot be ruled out. It is likely that 2000 PN9 is a YORP-evolved object, and may be an example of YORP equilibrium or self-limitation. [ABSTRACT FROM AUTHOR]

D-type asteroids are among the most primitive small bodies of the solar system. Believed to be formed in the outer solar system, a minor fraction of these faint objects can be found in the near-Earth region. Some were suspected to be extinct comets disguised as asteroids. If D-type near-Earth asteroids could represent extinct comets, they would offer us a unique opportunity to investigate the relationship between two classes of minor bodies in our solar system. To provide new insights into D-type asteroids' composition and dynamical evolution and the possible relation with comets, we introduce the mission concept CARINA (Comet Asteroid Relation INvestigation and Analysis). CARINA will visit and collect a sample from the asteroid 2002 AT4 and address key scientific questions related to our understanding of the early solar system evolution, and the origins of water and life on the early Earth. This paper outlines the scientific motivation and the means for the sample return. The spacecraft is equipped with a sampling ring to perform in-situ analysis and to collect, in a "touch and go" manner, samples from the surface and subsurface of the asteroid. A capsule is expected to return the samples to Earth in pristine conditions for detailed and extended analysis. These would represent a rare contribution to our meteorite collection since it would be the first time that material from a D class asteroid would be collected. • CARINA is proposed to be the first sample return mission to a D-type asteroid. • The mission would address the relationship between comets and asteroids. • CARINA's science case and objectives, subsystems engineering design, and mission analysis are presented. [ABSTRACT FROM AUTHOR]

Meteorites provide an important source of information about the formation and composition of asteroids, because the level of accuracy of studies and analyses performed in a laboratory cannot be achieved by any ground- or space-based observation. To better understand what asteroid types a meteorite represents, it is crucial to identify the body they originated from. In this paper, we aim to determine possible parent bodies for the known meteorite falls among the known population of near-Earth asteroids (NEAs). By using the similarity criterion DN , based on geocentric quantities, we found 20 possible NEA–meteorite pairs. By performing additional numerical simulations of the backward dynamics, we found that 12 of these pairs may be associated with a possible separation event from the progenitor NEA, while the remaining 8 pairs appear to be ambiguous or random associations. The most interesting are the Pribram and Neuschwanstein meteorites, which are dynamically associated with (482488) 2012 SW20 with a common separation age dating back to about 20–30 kyr ago, and the Motopi Pan meteorite, which has three candidate parent bodies: (454100) 2013 BO73, 2017 MC3, and 2009 FZ4. The average time of separation between our meteorite list and the progenitor body appears to be about 10 kyr, a time consistent with what is expected from the collision frequency of small NEAs. Based on our results, we suggest that about 25 per cent of meteorites do not originate in the main belt, but mainly from little collision events happening between NEAs in the inner Solar system. [ABSTRACT FROM AUTHOR]

We study nodal librations of outer particles in the framework of the elliptical restricted three-body problem including general relativity (GR) effects. From an analytical treatment based on secular interactions up to quadrupole level, we derive equations that define the nodal libration region of an outer test particle, which depends on the physical and orbital parameters of the bodies of the system. From this, we analyse how the GR constrains the semimajor axis of outer test particles that experience nodal librations under the effects of an inner planet around a single stellar component. Such an upper limit of the semimajor axis, which is called a 2,lim, depends on the mass of the star m s, the mass m 1, the semimajor axis a 1, and the eccentricity e 1 of the inner planet, and the eccentricity e 2 of the outer test particle. On the one hand, our results show that the greater m 1, a 1, and e 2 and the smaller m s, the greater the value of a 2,lim. On the other hand, for fixed m s, m 1, a 1, and e 2, a 2,lim does not strongly depend on e 1, except for large values of such an orbital parameter. We remark that N -body experiments of particular scenarios that include GR show results consistent with the analytical criteria derived in this research. Moreover, the study of hypothetical small body populations of real systems composed of a single star and an inner planetary-mass companion show that the GR effects can play a very important role in their global dynamics. [ABSTRACT FROM AUTHOR]

Dynamic exploration around non-spherical bodies has increased in recent decades due to the interest in studying the motion of spacecraft orbits, moons, and particle ring around these bodies. The dynamic structure around these objects is defined by regular and chaotic regions. The Poincaré surface of section technique allows mapping these regions, identifying the location of resonances, and the size of regular and chaotic zones, thus helping us to understand the dynamics around these bodies. Using this technique, we map in the a – e space the stable and unstable regions around ellipsoidal bodies, such as the dwarf planet Haumea, the centaur Chariklo, and other five hypothetical bodies, in which we keep part of the physical parameters of Haumea but we varied its period of rotation and ellipticity, to analyse the impact of these alterations in the extensions of the stable and unstable regions due to first kind orbits and spin-orbit type resonances. We identified a large region of stability, in semimajor axis and eccentricity, due to the first kind orbits. Periodic orbits of the first kind are present in a large semimajor axis interval for all considered systems and have almost zero eccentricity, while resonant and quasi-periodic orbits have high eccentricities. Furthermore, we identified the bifurcation of the 2:6 resonance when there is a spin reduction of a body with the same physical parameters as Haumea. This bifurcation generates a chaotic region, reducing the extension of the stability zone. [ABSTRACT FROM AUTHOR]

Recent observations and detections of interstellar objects (ISOs) passing through the Solar system have sparked a wave of interest into these objects. Although rare, these ISOs can be captured into bound orbits around the Sun. In this study, we investigate the novel idea of capture of ISOs into near-Earth orbits and find that a steady population of ISOs exists among the current population of near-Earth objects (NEOs). Using numerical simulations, we find that the capture of ISOs into near-Earth orbits is dominated by Jupiter that is 104 times more efficient in capturing ISOs compared to Earth. Captured ISOs are more likely to be in orbits with high eccentricities and low inclinations. We also investigate the stability of captured ISOs and find that they are generally unstable and have an average survival lifetime of ∼1 Myr, consistent with lifetime of NEOs originating from outer asteroid belt, and are ejected from the Solar system due to interactions with other planets or the Sun. Our results have important implications for understanding the population of ISOs in the Solar system and possible future detection. We find that about one to a few 50–70 m sized captured ISOs among NEOs would be detectable by Vera Rubin Observatory over its lifetime. By detecting and studying captured ISOs, we can learn about the properties and origins of such objects, and the formation and evolution of exoplanetary systems and even our Solar system. [ABSTRACT FROM AUTHOR]

We conducted optical polarimetry and near-infrared spectroscopy of Japan Aerospace Exploration Agency (JAXA)'s Hayabusa2# mission target, (98943) 2001 CC21, in early 2023. Our new observations indicate that this asteroid has a polarimetric inversion angle of ∼20°, absorption bands around 0.9 and 1.9 μ m, and a geometric albedo of 0.23 ± 0.04. All these features are consistent with those of S types but inconsistent with L types. Based on this evidence, we conclude that JAXA's Hayabusa2# spacecraft will explore an S-type asteroid (more specifically, an L or LL chondrite-like object) with albedo and size (0.44–0.53 km when we assume the absolute magnitude of 18.8) similar to (25143) Itokawa. [ABSTRACT FROM AUTHOR]

Main Belt asteroid (152830) Dinkinesh will be the first fly-by target of the Lucy mission on 2023 November 1, during its cruise to the Trojan clouds. We report our photometric time series observations of this target performed on 14 nights over nearly three months during the 2022-23 apparition with the 1.23-m telescope at Calar Alto, Spain, aimed at determining its rotation and photometric properties. We find that Dinkinesh is a slow rotator (P syn = 52.67 ± 0.04 h) with a moderately large light-curve amplitude (A  = 0.39 ± 0.02), which implies an axial ratio a / b ≳ 1.43. Its photometric parameters in the HG-system are H R = 17.17 ± 0.04 and G R = 0.378 ± 0.035 with a colour index |$\rm {V \!-\! R}$|  = 0.455 ± 0.025. A fit to the IAU |$\rm {H,G_1,G_2}$| system results in |$H_{\rm R-(H,G_1,G_2)}$|  = 17.17 ± 0.14; G 1  = 0.37 ± 0.17 and G 2  = 0.43 ± 0.04. Assuming that Dinkinesh's albedo lies within ±2σ of the average value for small S-class asteroids, its spherical surface-equivalent diameter is between 0.66 and 1.36 km. [ABSTRACT FROM AUTHOR]

The dynamical interaction of minor bodies (such as comets or asteroids) with planets plays an essential role in the planetary system's architecture and evolution. As a result of these interactions, structures such as the Kuiper belt and the Oort cloud can be created. In particular, the collision of minor bodies with planets can drastically change the planet's internal and orbital evolution. We present an analytical formulation to determine the collision time-scale for a minor body to impact a planet for arbitrary geometry. By comparing with a suite of detailed N -body simulations and an analytical method for collision time-scales in the Solar system, we confirmed the accuracy of our analytical formulation. As a proof of concept, we focused on the collision time-scales of minor bodies similar to the Jupiter-family comets and the long-period comets with a Jupiter-like planet. We show that our analytical method yields in good agreement with the numerical simulations. The formalism presented here thus provides a succinct and accurate alternative to numerical calculations. [ABSTRACT FROM AUTHOR]

Airless bodies are subjected to space-weathering effects that modify the first few microns of their surface. Therefore, understanding their impact on the optical properties of asteroids is key to the interpretation of their color variability and infrared reflectance observations. The recent Hayabusa2 sample return mission to asteroid Ryugu offers the first opportunity to study these effects, in the case of the most abundant spectral type among the main-asteroid belt, C-type objects. This study employs vibrational electron energy-loss spectroscopy in the transmission electron microscope to achieve the spatial resolution required to measure the distinct mid-infrared spectral signature of Ryugu's space-weathered surface. The comparison with the spectrum of the pristine underlying matrix reveals the loss of structural -OH and C-rich components in the space-weathered layers, providing direct experimental evidence that exposure to the space environment tends to mask the optical signatures of phyllosilicates and carbonaceous matter. Our findings should contribute to rectifying potential underestimations of water and carbon content of C-type asteroids when studied through remote sensing with new-generation telescopes.

While contact binary objects are common in the solar system, their formation mechanism is unclear. In this work we examine several contact binaries and calculate the necessary strength parameters that allow the two lobes to merge without the smaller of the two being gravitationally destroyed by the larger. We find a small but nonzero amount of cohesion or a large friction angle is required for the smaller lobe to survive the merging process, consistent with observations. This means it is possible for two previously separated rubble piles to experience a collapse of their mutual orbit and form a contact binary. The necessary strength required to survive this merger depends on the relative size, shape, and density of the body, with prolate shapes requiring more cohesion than oblate shapes.

The NASA New Horizons Venetia Burney Student Dust Counter (SDC) measures dust particle impacts along the spacecraft’s flight path for grains with mass ≥10 ^−12 g, mapping out their spatial density distribution. We present the latest SDC dust density, size distribution, and flux measurements through 55 au and compare them to numerical model predictions. Kuiper Belt objects (KBOs) are thought to be the dominant source of interplanetary dust particles in the outer solar system due to both collisions between KBOs and their continual bombardment by interstellar dust particles. Continued measurements through 55 au show higher than model-predicted dust fluxes as New Horizons approaches the putative outer edge of the Kuiper Belt (KB). We discuss potential explanations for the growing deviation: radiation pressure stretches the dust distribution to further heliocentric distances than its parent body distribution; icy dust grains undergo photosputtering that rapidly increases their response to radiation pressure forces and pushes them further away from the Sun; and the distribution of KBOs may extend much further than existing observations suggest. Ongoing SDC measurements at even larger heliocentric distances will continue to constrain the contributions of dust production in the KB. Continued SDC measurements remain crucial for understanding the Kuiper Belt and the interpretation of dust disks around other stars.

Contact. Potentially hazardous asteroids (PHA) in Earth-crossing orbits pose a constant threat to life on Earth. Several mitigation methods have been proposed, and the most feasible technique appears to be the disintegration of the impactor and the generation of a fragment cloud by explosive penetrators at interception. However, mitigation analyses tend to neglect the effect of orbital dynamics on the trajectory of fragments. Aims. We aim to study the effect of orbital dynamics of the impactor's cloud on the number of fragments that hit the Earth, assuming different interception dates. We investigate the effect of self-gravitational cohesion and the axial rotation of the impactor. Methods. We computed the orbits of 105 fragments with a high-precision direct N-body integrator of the eighth order, running on GPUs. We considered orbital perturbations from all large bodies in the Solar System and the self-gravity of the cloud fragments. Results. Using a series of numerical experiments, we show that orbital shear causes the fragment cloud to adopt the shape of a triaxial ellipsoid. The shape and alignment of the triaxial ellipsoid are strongly modulated by the cloud's orbital trajectory and, hence, the impact cross-section of the cloud with respect to the Earth. Therefore, the number of fragments hitting the Earth is strongly influenced by the orbit of the impactor and the time of interception. A minimum number of impacts occur for a well-defined orientation of the impactor rotational axis, depending on the date of interception. Conclusions. To minimise the lethal consequences of an PHA's impact, a well-constrained interception timing is necessary. A too-early interception may not be ideal for PHAs in the Apollo or Aten groups. Thus, we find that the best time to intercept PHA is when it is at the pericentre of its orbit. [ABSTRACT FROM AUTHOR]