Early collisional evolution of TNOs

Any early or late dynamical instability in the outer Solar system should have left their footprint on the trans-Neptunian object (TNO) populations. Here, we study the collisional and dynamical evolution of such populations numerically by an updated version of ALICANDEP, which suitably takes into account the onset of an early dynamical instability. Key parameters for collisional and dynamical evolution are chosen to match results with current observables. The new model (ALICANDEP-22) considers an original region located between 22 and 30 au, containing 20–30 M_Earth from which bodies are either dynamically ejected from the region or implanted into the current plutinos and hot classical trans-Neptunian belt. An in situ population of objects is also present since the beginning, corresponding to the current cold-classical population. Collisional and dynamical evolution is allowed starting from initial conditions accounting for streaming instability models and observational constraints. ALICANDEP-22 successfully reproduces observational constraints as well as the shape of the size-frequency distribution expected for the Trojan population. The model concludes that Arrokoth is likely a primordial body but cannot be conclusive on the origin of comet 67P/Churyumov–Gerasimenko. The current presence of bodies larger than Pluto in the outer TNO population – waiting to be discovered – is compatible with the initial distributions that allow the model to match current constraints

Collisional evolution of the trans-Neptunian region in an early dynamical instability scenario

Any early or late dynamical instability in the outer Solar system should have left their footprint on the trans-Neptunian object (TNO) populations. Here, we study the collisional and dynamical evolution of such populations numerically by an updated version of ALICANDEP, which suitably takes into account the onset of an early dynamical instability. Key parameters for collisional and dynamical evolution are chosen to match results with current observables. The new model (ALICANDEP-22) considers an original region located between 22 and 30 au, containing 20-30 Earth mass from which bodies are either dynamically ejected from the region or implanted into the current plutinos and hot classical trans-Neptunian belt. An in situ population of objects is also present since the beginning, corresponding to the current cold-classical population. Collisional and dynamical evolution is allowed starting from initial conditions accounting for streaming instability models and observational constraints. ALICANDEP-22 successfully reproduces observational constraints as well as the shape of the size-frequency distribution expected for the Trojan population. The model concludes that Arrokoth is likely a primordial body but cannot be conclusive on the origin of comet 67P/Churyumov-Gerasimenko. The current presence of bodies larger than Pluto in the outer TNO population - waiting to be discovered - is compatible with the initial distributions that allow the model to match current constraints

Physical properties of the trans-Neptunian binary 2000 YW₁₃₄

The study of trans-Neptunian binaries (TNBs) remains one of the most active areas of progress in understanding the solar system beyond Neptune. TNBs have been found in every dynamical population of the trans-Neptunian region (Noll et al. 2020), with proportions ranging from 29 % in the cold classical population to 5.5 % for the remaining classes combined (Brunini 2020). The formation of the contact TNB Arrokoth is one of the challenges that formation models face nowadays. The current angular momentum of Arrokoth is too low and the current binary formation scenarios, by either rotational fission or streaming instability (Nesvorný et al. 2019), require also loss of angular momentum (McKinnon et al. 2020). Additionally, formation mechanisms of close binaries may be distinct from those for the wider pairs. As the angular momentum of a system approaches that of an object spinning near its critical rotation period, rotational fission is the most likely explanation for their formation (Descamps et al. 2008), which is thought to be the case for the proposed satellites of Varuna and 2002 TC302 systems (Fernández-Valenzuela et al. 2019; Ortiz et al. 2020). If close TNBs turn out to be common for objects rotating close to the breakup limit, that could reveal important clues about angular momentum evolution during accretion for TNOs (Petit et al. 2011). However, characterizing binary systems at such distances is challenging. From the ~120 known TNBs, only around 40 have their mutual orbit fully determined, let alone physical characterization. 2000 YW134 is a TNB in a 3:8 resonance with an orbital semi-major axis of 57.4 au (a rare occurrence). On February 23rd, 2022, it occulted the Gaia EDR3 star 627356458358636544 (V = 17.1 mag). The stellar occultation was initially predicted using the JPL orbit solution #24, and updated using data from the 1.5-m and 1.23-m telescopes at Sierra Nevada and Calar Alto Observatories, using the same methodology as explained in Ortiz et al (2020). From the 17 observatories involved, seven reported positive chords, with five of them corresponding to the main body and the other two chords corresponding to its satellite. We are currently working on the analysis of these data in order to obtain the physical properties that characterize the system. Preliminary results show that the lower limit for the equivalent projected diameter of the satellite is twice the previously estimated size from HST observations (Stephens et al. 2006). We will also compare our results with the area-equivalent diameter and albedo obtained using thermal data from Herschel and Spitzer observations (Farkas-Takács et al. 2020)

The Trans-Neptunian Object (19521) Chaos as seen from stellar occultations and photometry observations

<p>Trans-Neptunian Objects (TNOs) are important solar system bodies that carry valuable information on the first stages of our solar system and its evolution. The TNO named (19521) Chaos (formerly known as 1998 WH24) is a large object, presumably in the 600-km size range judging by its approximate absolute magnitude and assuming a typical geometric albedo for a TNO. This is a comparable size to that of the three largest asteroids in the main asteroid belt. Therefore, it is an important body to study and characterize through stellar occultations and through other techniques. On October 20th, 2020, a three-chord stellar occultation was recorded by our team (Vara-Lubiano et al. 2021) within the context of the Lucky Star international collaboration* on stellar occultations by TNOs and other outer solar system bodies, and recently, on January 14th, 2022, another stellar occultation by Chaos has been recorded, whose main preliminary results will be presented. In this case 24 sites participated in the campaign. There were 8 positive detections and 3 near misses. The analysis of this occultation combined with the previous one and with photometry data obtained along 17 years (within our own TNO observing program) will be presented. We expect to derive an accurate size and shape as well as an accurate geometric albedo, which can be compared with radiometric measurements. We also expect to provide constraints on the spin axis orientation. The fact that no satellite around Chaos has been discovered so far means that we do not know the system mass so we cannot infer a bulk density for the body to compare with hydrostatic equilibrium computations, but we can derive other useful constraints.</p> <p>*Lucky Star (LS) is an EU-funded research activity to obtain physical properties of distant Solar System objects using stellar occultations. LS collaboration agglomerates the efforts of the Paris, Granada, and Rio teams. https://lesia.obspm.fr/lucky-star/ </p&gt

Visionado y análisis de actuaciones judiciales en clase: La elaboración de un dosier digital de videos, escritos procesales, resoluciones judiciales y una metodología docente para su visionado y análisis

Memoria del Proyecto de innovación docente: «Visionado y análisis de actuaciones judiciales en clase: La elaboración de un dosier digital de videos, escritos procesales, resoluciones judiciales y una metodología docente para su visionado y análisis (Convocatoria 2023-2024, proyecto núm. 55).Depto. de Derecho Procesal y Derecho PenalFac. de DerechoFALSEsubmitte