Suchergebnisse

La Universidad Pedagógica Veracruzana (UPV) como institución formadora de docentes en educación básica, durante la crisis sanitaria por COVID-19 estableció estrategias académicas para el aprendizaje en línea, autónomo y auto organizado. El objetivo fue analizar las apreciaciones del aprendizaje en línea de los aprendientes de la licenciatura de educación básica de la UPV en el contexto de la pandemia. La metodología de la investigación se fundamentó bajo el método exploratorio, en el paradigma positivista, con enfoque mixto, de tipo no experimental y diseño descriptivo. La herramienta de recolección de datos que se utilizó fue un cuestionario con ítems en escala de Likert y abiertas y se suministró a una muestra de 3,306 sujetos, todos ellos inscritos en el periodo febrero-julio de 2021. Los resultados obtenidos mostraron una aceptación favorable en el aspecto pedagógico, así como la adaptación al trabajo a distancia. Sin embargo, es notoria la brecha digital entre los participantes debido a las localidades en donde radican, ya que algunas de ellas son de tipo indígena y rural, en donde la cobertura de Internet es de difícil acceso. A partir de lo anterior, no se encontraron diferencias significativas de género en los sentimientos expresados por los aprendientes. Por último, a pesar de que el proceso formativo continuó en línea, los estudiantes señalaron que la interacción presencial es imprescindible para la socialización de los aprendizajes, dado que no es lo mismo interactuar a distancia.

[ES] El presente artículo se enmarca dentro de la arquitectura contemporánea de Paraguay y tiene por objetivo aproximarnos a la utilización del dibujo a mano alzada como herramienta de transmisión de conocimiento técnico entre el arquitecto y el artesano, como parte del proceso constructivo de una obra arquitectónica. Este aspecto será analizado a partir de la lectura de casos, que consideran como base de datos las ilustraciones originales de tres edificios, como un testimonio vivo del proceso de obra. ; [EN] This article is framed within the contemporary architecture of Paraguay and aims to analyze freehand drawing as a tool to transmit technical knowledge between the architect and the craftsman during construction of an architectural work. This process will be analyzed by reading case studies and using the original illustrations from three different architectural projects as a living testimony of the work process. ; The research has been funded by the Ministry of Culture, Arts and Heritage of the Government of Chile, under the Scholarships Chile CREA, Call 2019. ; Uribe Ortiz, JL. (2020). El dibujo a mano alzada como herramienta de resolución técnica: estudio de tres casos en la arquitectura contemporánea de Paraguay. EGA Expresión Gráfica Arquitectónica. 25(39):86-97. https://doi.org/10.4995/ega.2020.13952 ; OJS ; 86 ; 97 ; 25 ; 39 ; BRESSON, R. "Bresson por Bresson. Entrevistas 1943 - 1983" ["Bresson, by Bresson: Interviews, 1943 to 1983"]. Editorial in El cuenco de plata [The Silver Plate], Buenos Aires, Argentina (2014). ; CORVALÁN, Javier. "Un fin del mundo. Fragmento de El libro negro" ["An End of the World: Fragment of the Black Book"] in RITA: Revista Indexada de Textos Académicos, año 1, N° 1. [Indexed Journal of Academic Texts, Year 1, Issue 1]. Madrid, Spain (2014). ; FORTY, Adrián. "La palabra y el concepto" ["The World and the Concept"] in Ediciones ARQ [Architectural Editions], Santiago, Chile (2018). ; GIURIA, Juan. "La arquitectura en el Paraguay" [Architecture in Paraguay], in Instituto de ...

RESUMEN Durante los últimos veinte años la contingencia política y las crisis económicas han orientado la mirada de la escena arquitectónica contemporánea hacia contextos periféricos, promoviendo una arquitectura surgida bajo ámbitos de escasez y articulada por su abundante cultura material. Lo anterior ha definido una nueva narrativa arquitectónica orientada por la incidencia del proceso artesanal como parte activa de la obra arquitectónica. Una arquitectura al margen la cual se articula a partir de la reaparición del quehacer material del artesano y el saber ancestral del hombre como una condición contemporánea de la arquitectura. Es ahí donde el presente artículo se inserta, a partir de una serie de planteamientos que orientan los márgenes de acción de la nueva arquitectura contemporánea en Paraguay, cuya narrativa arquitectónica será desplegada a partir de la lectura de tres casos de estudio agrupados en los materiales característicos proporcionados por ese territorio.SUMMARY During the past twenty years, political contingency and frequent economic crises within Paraguay have oriented their view of contemporary architecture towards peripheral contexts, resulting in a style of architecture which emerged under scarce resources, but articulated by its abundant material culture. The above has defined a new architectural narrative, oriented by the artisanal process as an active part of architectural work. Paraguay enjoys an "architecture on the margin," which is typified by the reappearance of material craftsman paired with the ancestral knowledge of man as a contemporary condition. This is the context of the present article, based on a series of approaches that guide the margins of action of the new contemporary architecture in Paraguay, whose architectural narrative will be illustrated by the analysis of three case studies, grouped in the characteristic materials provided by that territory.

Durante los últimos veinte años la contingencia política y las crisis económicas han orientado la mirada de la escena arquitectónica contemporánea hacia contextos periféricos, promoviendo una arquitectura surgida bajo ámbitos de escasez y articulada por su abundante cultura material. Lo anterior ha definido una nueva narrativa arquitectónica orientada por la incidencia del proceso artesanal como parte activa de la obra arquitectónica. Una arquitectura al margen la cual se articula a partir de la reaparición del quehacer material del artesano y el saber ancestral del hombre como una condición contemporánea de la arquitectura. Es ahí donde el presente artículo se inserta, a partir de una serie de planteamientos que orientan los márgenes de acción de la nueva arquitectura contemporánea en Paraguay, cuya narrativa arquitectónica será desplegada a partir de la lectura de tres casos de estudio agrupados en los materiales característicos proporcionados por ese territorio. ; During the past twenty years, political contingency and frequent economic crises within Paraguay have oriented their view of contemporary architecture towards peripheral contexts, resulting in a style of architecture which emerged under scarce resources, but articulated by its abundant material culture. The above has defined a new architectural narrative, oriented by the artisanal process as an active part of architectural work. Paraguay enjoys an "architecture on the margin," which is typified by the reappearance of material craftsman paired with the ancestral knowledge of man as a contemporary condition. This is the context of the present article, based on a series of approaches that guide the margins of action of the new contemporary architecture in Paraguay, whose architectural narrative will be illustrated by the analysis of three case studies, grouped in the characteristic materials provided by that territory.

Schindler, K. et. al. ; Context. A stellar occultation by a trans-Neptunian object (TNO) provides an opportunity to probe the size and shape of these distant solar system bodies. In the past seven years, several occultations by TNOs have been observed, but mostly from a single location. Only very few TNOs have been sampled simultaneously from multiple locations. Sufficient data that enable a robust estimation of shadow size through an ellipse fit could only be obtained for two objects. Aims. We present the first observation of an occultation by the TNO 2007 UK126 on 15 November 2014, measured by three observers, one nearly on and two almost symmetrical to the shadow's centerline. This is the first multi-chord dataset obtained for a so-called detached object, a TNO subgroup with perihelion distances so large that the giant planets have likely not perturbed their orbits. We also revisit Herschel/PACS far-infrared data, applying a new reduction method to improve the accuracy of the measured fluxes. Combining both datasets allows us to comprehensively characterize 2007 UK126. Methods. We use error-in-variable regression to solve the non-linear problem of propagating timing errors into uncertainties of the ellipse parameters. Based on the shadow's size and a previously reported rotation period, we expect a shape of a Maclaurin spheroid and derive a geometrically plausible size range. To refine our size estimate of 2007 UK126, we model its thermal emission using a thermophysical model code. We conduct a parametric study to predict far-infrared fluxes and compare them to the Herschel/PACS measurements. Results. The favorable geometry of our occultation chords, combined with minimal dead-time imaging, and precise GPS time measurements, allow for an accurate estimation of the shadow size (best-fitting ellipse with axes 645.80 +/- 5.68 km x 597.81 +/- 12.74 km) and the visual geometric albedo (p(V) = 15.0 +/- 1.6%). By combining our analyses of the occultation and the far-infrared data, we can constrain the effective diameter of 2007 UK126 to d(eff) = 599-629 km. We conclude that subsolar surface temperatures are in the order of approximate to 50 55 K. ; K.S. has been supported financially by a one-year fellowship from the German Academic Exchange Service (DAAD) during his stay at NASA Ames Research Center, CA as part of his Ph.D. research. K.S. would also like to thank the Universities Space Research Association (USRA) for their support throughout his thesis. T.M., C.K. and J.L.O. have received funding from the European Union's Horizon 2020 Research and Innovation Programme, under Grant Agreement No. 687378. C.K. has been supported by the PECS grant # 4000109997/13/NL/KML of the Hungarian Space Office and the European Space Agency, the K-104607 grant of the Hungarian Research Fund (OTKA), and the GINOP-2.3.2-15-2016 00003 grant of the National Research, Development and Innovation Office of Hungary (NKFIH). J.L.O. acknowledges support from Proyecto de Excelencia J.A. 2012-FQM1776. ; Peer reviewed

Context. Time series observations of the dwarf planet Haumea and the Plutinos 2003 VS and 2003 AZ with Herschel/PACS are presented in this work. Thermal emission of these trans-Neptunian objects (TNOs) were acquired as part of the >TNOs are Cool> Herschel Space Observatory key programme. Aims. We search for the thermal light curves at 100 and 160 μm of Haumea and 2003 AZ, and at 70 and 160 μm for 2003 VS by means of photometric analysis of the PACS data. The goal of this work is to use these thermal light curves to obtain physical and thermophysical properties of these icy Solar System bodies. Methods. When a thermal light curve is detected, it is possible to derive or constrain the object thermal inertia, phase integral and/or surface roughness with thermophysical modeling. Results. Haumea's thermal light curve is clearly detected at 100 and 160 μm. The effect of the reported dark spot is apparent at 100 μm. Different thermophysical models were applied to these light curves, varying the thermophysical properties of the surface within and outside the spot. Although no model gives a perfect fit to the thermal observations, results imply an extremely low thermal inertia (0.73) for Haumea's surface. We note that the dark spot region appears to be only weakly different from the rest of the object, with modest changes in thermal inertia and/or phase integral. The thermal light curve of 2003 VS is not firmly detected at 70 μm and at 160 μm but a thermal inertia of (2 ± 0.5) MKS can be derived from these data. The thermal light curve of 2003 AZ is not firmly detected at 100 μm. We apply a thermophysical model to the mean thermal fluxes and to all the Herschel/PACS and Spitzer/MIPS thermal data of 2003 AZ, obtaining a close to pole-on orientation as the most likely for this TNO. Conclusions. For the three TNOs, the thermal inertias derived from light curve analyses or from the thermophysical analysis of the mean thermal fluxes confirm the generally small or very small surface thermal inertias of the TNO population, which is consistent with a statistical mean value Γ = 2.5 ± 0.5 MKS.© ESO, 2017. ; The research leading to these results has received funding from the European Union's Horizon 2020 Research and Innovation Programme, under Grant Agreement No. 687378. P. Santos-Sanz and J. L. Ortiz would like to acknowledge financial support by the Spanish grant AYA-2014-56637-C2-1-P and the Proyecto de Excelencia de la Junta de Andalucia J.A. 2012-FQM1776. C. Kiss acknowledges financial support from NKFIH grant GINOP-2.3.2-15-2016-00003. E. Vilenius was supported by the German DLR project number 50 OR 1108. R. Duffard acknowledges financial support from the MINECO for his Ramon y Cajal Contract. ; Peer Reviewed

Full list of authors: Santos-Sanz, P.; Ortiz, J. L.; Sicardy, B.; Benedetti-Rossi, G.; Morales, N.; Fernández-Valenzuela, E.; Duffard, R.; Iglesias-Marzoa, R.; Lamadrid, J. L.; Maícas, N.; Pérez, L.; Gazeas, K.; Guirado, J. C.; Peris, V.; Ballesteros, F. J.; Organero, F.; Ana-Hernández, L.; Fonseca, F.; Alvarez-Candal, A.; Jiménez-Teja, Y. Vara-Lubiano, M.; Braga-Ribas, F.; Camargo, J. I. B.; Desmars, J.; Assafin, M.; Vieira-Martins, R.; Alikakos, J.; Boutet, M.; Bretton, M.; Carbognani, A.; Charmandaris, V.; Ciabattari, F.; Delincak, P.; Fuambuena Leiva, A.; González, H.; Haymes, T.; Hellmich, S.; Horbowicz, J.; Jennings, M.; Kattentidt, B.; Kiss, Cs; Komžík, R.; Lecacheux, J.; Marciniak, A.; Moindrot, S.; Mottola, S.; Pal, A.; Paschalis, N.; Pastor, S.; Perello, C.; Pribulla, T.; Ratinaud, C.; Reyes, J. A.; Sanchez, J.; Schnabel, C.; Selva, A.; Signoret, F.; Sonbas, E.; Alí-Lagoa, V.--This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted reuse, distribution, and reproduction in any medium, provided the original work is properly cited. ; We predicted a stellar occultation of the bright star Gaia DR1 4332852996360346368 (UCAC4 385-75921) (mV = 14.0 mag) by the centaur 2002 GZ32 for 2017 May 20. Our latest shadow path prediction was favourable to a large region in Europe. Observations were arranged in a broad region inside the nominal shadow path. Series of images were obtained with 29 telescopes throughout Europe and from six of them (five in Spain and one in Greece) we detected the occultation. This is the fourth centaur, besides Chariklo, Chiron, and Bienor, for which a multichord stellar occultation is reported. By means of an elliptical fit to the occultation chords, we obtained the limb of 2002 GZ32 during the occultation, resulting in an ellipse with axes of 305 ± 17 km × 146 ± 8 km. From this limb, thanks to a rotational light curve obtained shortly after the occultation, we derived the geometric albedo of 2002 GZ32 (pV = 0.043 ± 0.007) and a 3D ellipsoidal shape with axes 366 km × 306 km × 120 km. This shape is not fully consistent with a homogeneous body in hydrostatic equilibrium for the known rotation period of 2002 GZ32. The size (albedo) obtained from the occultation is respectively smaller (greater) than that derived from the radiometric technique but compatible within error bars. No rings or debris around 2002 GZ32 were detected from the occultation, but narrow and thin rings cannot be discarded. © 2020 The Author(s) Published by Oxford University Press on behalf of Royal Astronomical Society. ; P.S-S. acknowledges financial support by the Spanish grant AYA-RTI2018-098657-J-I00 'LEO-SBNAF' (MCIU/AEI/FEDER, UE). PS-S, JLO, NM, and RD acknowledge financial support from the State Agency for Research of the Spanish MCIU through the 'Center of Excellence Severo Ochoa' award for the Instituto de Astrofisica de Andalucia (SEV-2017-0709), they also acknowledge the financial support by the Spanish grant AYA-2017-84637-R and the Proyecto de Excelencia de la Junta de Andalucia J.A. 2012-FQM1776. We acknowledge support of the publication fee by the CSIC Open Access Publication Support Initiative through its Unit of Information Resources for Research (URICI). The research leading to these results has received funding from the European Union's Horizon 2020 Research and Innovation Programme, under Grant Agreement no. 687378, as part of the project `Small Bodies Near and Far' (SBNAF). Part of the research leading to these results has received funding from the European Research Council under the European Community's H2020 (2014-2020/ERC Grant Agreement no. 669416 `LUCKY STAR'). E.F-V. acknowledges funding through the Preeminant Postdoctoral Program of the University of Central Florida. Part of the data were collected during the photometric monitoring observations with the robotic and remotely controlled observatory at the University of Athens Observatory -UOAO (Gazeas 2016). F.J.B. acknowledges financial support by the Spanish grant AYA2016-81065-C2-2-P. A.A-C. acknowledges support from FAPERJ (grant E26/203.186/2016) and CNPq (grants 304971/20162 and 401669/2016-5). A.C. acknowledges the use of the main telescope of theAstronomical Observatory of the Autonomous Region of the Aosta Valley (OAVdA). C.K. has been supported by the grants K125015 and GINOP-2.3.2-15-2016-00003 of the National Research, Development and Innovation Office, Hungary (NKFIH). T.P. and R.K. acknowledge support from the project ITMS No. 26220120029, based on the Research and development program financed from the European Regional Development Fund and from the Slovak Research and Development Agency -the contract No. APVV-150458. We are grateful to the CAHA and OSN staffs. This research is partially based on observations collected at Centro Astronomico Hispano-Aleman (CAHA) at Calar Alto, operated jointly by Junta de Andalucia and Consejo Superior de Investigaciones Cientificas (IAA-CSIC). This research was also partially based on observation carried out at the Observatorio de Sierra Nevada (OSN) operated by Instituto de Astrofisica de Andalucia (CSIC). This article is also based on observations made with the Liverpool Telescope operated on the island of La Palma by the Instituto de Astrofisica de Canarias in the Spanish Roque de losMuchachos Observatory. Partially based on observations made with the Tx40 telescope at the Observatorio Astrofisico de Javalambre in Teruel, a Spanish Infraestructura Cientifico-Tecnica Singular (ICTS) owned, managed and operated by the Centro de Estudios de Fisica del Cosmos de Arag on (CEFCA). Tx40 is funded with the Fondos de Inversiones de Teruel (FITE). This work has made use of data from the European Space Agency (ESA) mission Gaia (https://www.cosmos.esa.int/gaia), processed by the Gaia Data Processing and Analysis Consortium (DPAC, https://www.cosmos.esa.int/web/gaia/dpac/consortium).Funding for the DPAC has been provided by national institutions, in particular the institutions participating in the Gaia Multilateral Agreement. ; Peer reviewed

Ortiz, José Luis et. al. ; Haumea-one of the four known trans-Neptunian dwarf planets- is a very elongated and rapidly rotating body1-3. In contrast to other dwarf planets4-6, its size, shape, albedo and density are not well constrained. The Centaur Chariklo was the first body other than a giant planet known to have a ring system7, and the Centaur Chiron was later found to possess something similar to Chariklo's rings8,9. Here we report observations from multiple Earth-based observatories of Haumea passing in front of a distant star (a multichord stellar occultation). Secondary events observed around the main body of Haumea are consistent with the presence of a ring with an opacity of 0.5, width of 70 kilometres and radius of about 2,287 kilometres. The ring is coplanar with both Haumea's equator and the orbit of its satellite Hi'iaka. The radius of the ring places it close to the 3:1 mean-motion resonance with Haumea's spin period-that is, Haumea rotates three times on its axis in the time that a ring particle completes one revolution. The occultation by the main body provides an instantaneous elliptical projected shape with axes of about 1,704 kilometres and 1,138 kilometres. Combined with rotational light curves, the occultation constrains the three-dimensional orientation of Haumea and its triaxial shape, which is inconsistent with a homogeneous body in hydrostatic equilibrium. Haumea's largest axis is at least 2,322 kilometres, larger than previously thought, implying an upper limit for its density of 1,885 kilograms per cubic metre and a geometric albedo of 0.51, both smaller than previous estimates1,10,11. In addition, this estimate of the density of Haumea is closer to that of Pluto than are previous estimates, in line with expectations. No global nitrogen- or methane-dominated atmosphere was detected.© 2017 Macmillan Publishers Limited, part of Springer Nature. All rights reserved. ; J.L.O. acknowledges funding from Spanish and Andalusian grants MINECO AYA-2014-56637-C2-1-P and J. A. 2012-FQM1776 as well as FEDER funds. Part of the research leading to these results received funding from the European Union's Horizon 2020 Research and Innovation Programme, under grant agreement no. 687378. B.S. acknowledges support from the French grants 'Beyond Neptune' ANR-08-BLAN-0177 and 'Beyond Neptune II' ANR-11-1S56-0002. Part of the research leading to these results has received funding from the European Research Council under the European Community's H2020 (2014-2020/ERG grant agreement no. 669416 'Lucky Star'). A.P. and R.S. have been supported by the grant LP2012-31 of the Hungarian Academy of Sciences. All of the Hungarian contributors acknowledge the partial support from K-125015 grant of the National Research, Development and Innovation Office (NKFIH). G.B.-R., F.B.-R., F.L.R., R.V.-M., J.I.B.C., M.A., A.R.G.-J. and B.E.M. acknowledge support from CAPES, CNPq and FAPERJ. J.C.G. acknowledges funding from AYA2015-63939-C2-2-P and from the Generalitat Valenciana PROMETEOII/2014/057. K.H. and P.P. were supported by the project RVO:67985815. The Astronomical Observatory of the Autonomous Region of the Aosta Valley acknowledges a Shoemaker NEO Grant 2013 from The Planetary Society. We acknowledge funds from a 2016 'Research and Education' grant from Fondazione CRT. We also acknowledge the Slovakian project ITMS no. 26220120029. ; Peer Reviewed

We present time series photometry of Bienor in four observation campaigns from 2013 to 2016 and compare them with previous observations in the literature dating back to 2000. The results show a remarkable decline in the amplitude of the rotational light curve and in the absolute magnitude. This suggests that the angle between the rotation axis and the line of sight has changed noticeably during the last 16 yr as Bienor orbits the Sun. From the light-curve amplitude data, we are able to determine the orientation of the rotation axis of Bienor (β = 50 ± 3°, λp = 35 ± 8°). We are also able to constrain the b/a axial ratio of a triaxial Jacobi ellipsoidal body (with semi-axis a > b > c). The best fit is for b/a = 0.45±0.05, which corresponds to a density value of 594 kgm under the usual assumption of hydrostatic equilibrium and given that Bienor's rotational period is 9.17 h. However, the absolute magnitude of Bienor at several epochs is not well reproduced. We tested several explanations such as relaxing the hydrostatic equilibrium constraint, a large north-south asymmetry in the surface albedo of Bienor or even a ring system. When a ring system of similar characteristics to those of Chariklo and Chiron is included, we can fit both the lightcurve amplitude and absolute magnitude. In this case, the derived axial ratio is modified to b/a = 0.37 ± 0.10. The implied density is 678 kgm. Also, the existence of a ring is consistent with the spectroscopic detection of water ice on Bienor. Nevertheless, the other explanations cannot be discarded.© 2016 The Authors Published by Oxford University Press on behalf of the Royal Astronomical Society. ; Funding from Spanish grant AYA-2014-56637-C2-1-P is acknowledged, as is the Proyecto de Excelencia de la Junta de Andalucia, J. A. 2012-FQM1776. RD acknowledges the support of MINECO for his Ramon y Cajal Contract. The research leading to these results has received funding from the European Union's Horizon 2020 Research and Innovation Programme under Grant Agreement no. 687378. ; Peer Reviewed

All authors: Ortiz, J. L.; Santos-Sanz, P.; Sicardy, B.; Benedetti-Rossi, G.; Duffard, R.; Morales, N.; Braga-Ribas, F.; Fernández-Valenzuela, E.; Nascimbeni, V.; Nardiello, D.; Carbognani, A.; Buzzi, L.; Aletti, A.; Bacci, P.; Maestripieri, M.; Mazzei, L.; Mikuz, H.; Skvarc, J.; Ciabattari, F.; Lavalade, F. Scarfi, G.; Mari, J. M.; Conjat, M.; Sposetti, S.; Bachini, M.; Succi, G.; Mancini, F.; Alighieri, M.; Dal Canto, E.; Masucci, M.; Vara-Lubiano, M.; Gutiérrez, P. J.; Desmars, J.; Lecacheux, J.; Vieira-Martins, R.; Camargo, J. I. B.; Assafin, M.; Colas, F.; Beisker, W.; Behrend, R.; Mueller, T. G.; Meza, E.; Gomes-Junior, A. R.; Roques, F.; Vachier, F.; Mottola, S.; Hellmich, S.; Campo Bagatin, A.; Alvarez-Candal, A.; Cikota, S.; Cikota, A.; Christille, J. M.; Pál, A.; Kiss, C.; Pribulla, T.; Komžík, R.; Madiedo, J. M.; Charmandaris, V.; Alikakos, J.; Szakáts, R.; Farkas-Takács, A.; Varga-Verebélyi, E.; Marton, G.; Marciniak, A.; Bartczak, P.; Butkiewicz-Baķ, M.; Dudziński, G.; Alí-Lagoa, V.; Gazeas, K.; Paschalis, N.; Tsamis, V.; Guirado, J. C.; Peris, V.; Iglesias-Marzoa, R.; Schnabel, C.; Manzano, F.; Navarro, A.; Perelló, C.; Vecchione, A.; Noschese, A.; Morrone, L. ; Context. Deriving physical properties of trans-Neptunian objects is important for the understanding of our Solar System. This requires observational efforts and the development of techniques suitable for these studies. Aims. Our aim is to characterize the large trans-Neptunian object (TNO) 2002 TC302. Methods. Stellar occultations offer unique opportunities to determine key physical properties of TNOs. On 28 January 2018, 2002 TC302 occulted a mv ∼ 15.3 star with designation 593-005847 in the UCAC4 stellar catalog, corresponding to Gaia source 130957813463146112. Twelve positive occultation chords were obtained from Italy, France, Slovenia, and Switzerland. Also, four negative detections were obtained near the north and south limbs. This represents the best observed stellar occultation by a TNO other than Pluto in terms of the number of chords published thus far. From the 12 chords, an accurate elliptical fit to the instantaneous projection of the body can be obtained that is compatible with the near misses. Results. The resulting ellipse has major and minor axes of 543 ± 18 km and 460 ± 11 km, respectively, with a position angle of 3 ± 1 degrees for the minor axis. This information, combined with rotational light curves obtained with the 1.5 m telescope at Sierra Nevada Observatory and the 1.23 m telescope at Calar Alto observatory, allows us to derive possible three-dimensional shapes and density estimations for the body based on hydrostatic equilibrium assumptions. The effective diameter in equivalent area is around 84 km smaller than the radiometrically derived diameter using thermal data from Herschel and Spitzer Space Telescopes. This might indicate the existence of an unresolved satellite of up to ∼300 km in diameter, which is required to account for all the thermal flux, although the occultation and thermal diameters are compatible within their error bars given the considerable uncertainty of the thermal results. The existence of a potential satellite also appears to be consistent with other ground-based data presented here. From the effective occultation diameter combined with absolute magnitude measurements we derive a geometric albedo of 0.147 ± 0.005, which would be somewhat smaller if 2002 TC302 has a satellite. The best occultation light curves do not show any signs of ring features or any signatures of a global atmosphere. © ESO 2020. ; This research was partially based on data taken at the Sierra Nevada Observatory, which is operated by the Instituto de Astrofisica de Andalucia (CSIC). This research is also partially based on data taken at the German-Spanish Calar Alto observatory, which is jointly operated by the Max Planck Institute fur Astronomie and the Instituto de Astrofisica de Andalucia (CSIC). Part of the results were also based on observations taken at the 1.6m telescope on Pico dos Dias Observatory. This research was partially based on observations collected at the Schmidt telescope 67/92 cm (Asiago, Italy) of the INAF - Osservatorio Astronomico di Padova. Funding from Spanish projects AYA2014-56637-C2-1-P, AYA2017-89637-R, from FEDER, and Proyecto de Excelencia de la Junta de Andalucia 2012-FQM1776 is acknowledged. We would like to acknowledge financial support by the Spanish grant AYA-RTI2018-098657-JI00 "LEO-SBNAF" (MCIU/AEI/FEDER, UE) and the financial support from the State Agency for Research of the Spanish MCIU through the "Center of Excellence Severo Ochoa" award for the Instituto de Astrofisica de Andalucia (SEV- 2017-0709). Part of the research received funding from the European Union's Horizon 2020 Research and Innovation Programme, under grant agreement no. 687378 and from the ERC programme under Grant Agreement no. 669416 Lucky Star. The following authors acknowledge the respective CNPq grants: FB-R 309578/2017-5; RV-M 304544/2017-5, 401903/2016-8; J.I.B.C. 308150/2016-3; MA 427700/2018-3, 310683/2017-3, 473002/2013-2. This study was financed in part by the CoordenacAo de Aperfeiacoamento de Pessoal de Nivel Superior - Brasil (CAPES) - Finance Code 001 and the National Institute of Science and Technology of the e-Universe project (INCT do e-Universo, CNPq grant 465376/2014-2). GBR acknowledges CAPES-FAPERJ/PAPDRJ grant E26/203.173/2016, MA FAPERJ grant E-26/111.488/2013 and ARGJr FAPESP grant 2018/11239-8. E.F.-V. acknowledges support from the 2017 Preeminent Postdoctoral Program (P 3 ) at UCF. C.K., R.S., A.F-T., and G.M. have been supported by the K-125015 and GINOP-2.3.2-15-2016-00003 grants of the Hungarian National Research, Development and Innovation Office (NKFIH), Hungary. G.M. was also supported by the Hungarian National Research, Development and Innovation Office (NKFIH) grant PD-128 360. R.K. and T.P. were supported by the VEGA 2/0031/18 grant. We acknowledge the use of Occult software by D. Herald.

Full list of authors: Morgado, B. E.; Sicardy, B.; Braga-Ribas, F.; Desmars, J.; Gomes-Júnior, A. R.; Bérard, D.; Leiva, R.; Ortiz, J. L.; Vieira-Martins, R.; Benedetti-Rossi, G.; Santos-Sanz, P.; Camargo, J. I. B.; Duffard, R.; Rommel, F. L.; Assafin, M.; Boufleur, R. C.; Colas, F.; Kretlow, M.; Beisker, W.; Sfair, R.; Snodgrass, C.; Morales, N.; Fernández-Valenzuela, E.; Amaral, L. S.; Amarante, A.; Artola, R. A.; Backes, M.; Bath, K. -L.; Bouley, S.; Buie, M. W.; Cacella, P.; Colazo, C. A.; Colque, J. P.; Dauvergne, J. -L.; Dominik, M.; Emilio, M.; Erickson, C.; Evans, R.; Fabrega-Polleri, J.; Garcia-Lambas, D.; Giacchini, B. L.; Hanna, W.; Herald, D.; Hesler, G.; Hinse, T. C.; Jacques, C.; Jehin, E.; Jørgensen, U. G.; Kerr, S.; Kouprianov, V.; Levine, S. E.; Linder, T.; Maley, P. D.; Machado, D. I.; Maquet, L.; Maury, A.; Melia, R.; Meza, E.; Mondon, B.; Moura, T.; Newman, J.; Payet, T.; Pereira, C. L.; Pollock, J.; Poltronieri, R. C.; Quispe-Huaynasi, F.; Reichart, D.; de Santana, T.; Schneiter, E. M.; Sieyra, M. V.; Skottfelt, J.; Soulier, J. F.; Starck, M.; Thierry, P.; Torres, P. J.; Trabuco, L. L.; Unda-Sanzana, E.; Yamashita, T. A. R.; Winter, O. C.; Zapata, A.; Zuluaga, C. A.--This is an Open Access article, published by EDP Sciences, under the terms of the Creative Commons Attribution License (https://creativecommons.org/licenses/by/4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. ; Context. The Centaur (10199) Chariklo has the first ring system discovered around a small object. It was first observed using stellar occultation in 2013. Stellar occultations allow sizes and shapes to be determined with kilometre accuracy, and provide the characteristics of the occulting object and its vicinity. Aims. Using stellar occultations observed between 2017 and 2020, our aim is to constrain the physical parameters of Chariklo and its rings. We also determine the structure of the rings, and obtain precise astrometrical positions of Chariklo. Methods. We predicted and organised several observational campaigns of stellar occultations by Chariklo. Occultation light curves were measured from the datasets, from which ingress and egress times, and the ring widths and opacity values were obtained. These measurements, combined with results from previous works, allow us to obtain significant constraints on Chariklo's shape and ring structure. Results. We characterise Chariklo's ring system (C1R and C2R), and obtain radii and pole orientations that are consistent with, but more accurate than, results from previous occultations. We confirm the detection of W-shaped structures within C1R and an evident variation in radial width. The observed width ranges between 4.8 and 9.1 km with a mean value of 6.5 km. One dual observation (visible and red) does not reveal any differences in the C1R opacity profiles, indicating a ring particle size larger than a few microns. The C1R ring eccentricity is found to be smaller than 0.022 (3σ), and its width variations may indicate an eccentricity higher than ~0.005. We fit a tri-axial shape to Chariklo's detections over 11 occultations, and determine that Chariklo is consistent with an ellipsoid with semi-axes of 143.8-1.5+1.4, 135.2-2.8+1.4, and 99.1-2.7+5.4 km. Ultimately, we provided seven astrometric positions at a milliarcsecond accuracy level, based on Gaia EDR3, and use it to improve Chariklo's ephemeris. © B. E. Morgado et al. 2021. ; This work was carried out within the "Lucky Star" umbrella that agglomerates the efforts of the Paris, Granada and Rio teams, which is funded by the European Research Council under the European Community's H2020 (ERC Grant Agreement No. 669416). This research made use of SORA, a python package for stellar occultations reduction and analysis, developed with the support of ERC Lucky Star and LIneA/Brazil, within the collaboration Rio-Paris-Granada teams. This work has made use of data from the European Space Agency (ESA) mission Gaia (https://www.cosmos.esa.int/gaia), processed by the Gaia Data Processing and Analysis Consortium (DPAC, https://www.cosmos.esa.int/web/gaia/dpac/consortium). Part of this research is suported by INCT do e-Universo, Brazil (CNPQ grants 465376/2014-2). Based in part on observations made at the Laboratório Nacional de Astrofísica (LNA), Itajubá-MG, Brazil. The data include observations taken by the MiNDSTEp team at the Danish 1.54 m telescope at ESO's La Silla observatory" and "UGJ acknowledges funding from the European Union H2020-MSCA-ITN-2019 under grant no. 860470 (CHAMELEON) and from the Novo Nordisk Foundation Interdisciplinary Synergy Programme grant no. NNF19OC0057374. TRAPPIST-South is funded by the Belgian Fund for Scientific Research (Fond National de la Recherche Scientifique, FNRS) under the grant PDR T.0120.21. The authors acknowledge the use of Sonja Itting-Enke's C14 telescope and the facilities at the Cuno Hoffmeister Memorial Observatory (CHMO). The following authors acknowledge the respective CNPq grants: BEM 150612/2020-6; FB-R 314772/2020-0; RV-M 304544/2017-f5, 401903/2016-8; JIBC 308150/2016-3 and 305917/2019-6; MA 427700/2018-3, 310683/2017-3, 473002/2013-2. G.B.R. acknowledges CAPES-FAPERJ/PAPDRJ grant E26/203.173/2016 and CAPES-PRINT/UNESP grant 88887.571156/2020-00, MA FAPERJ grant E-26/111.488/2013 and ARGJr FAPESP grant 2018/11239-8. J.L.O., P.S.-S., R.D., and N.M. acknowledge financial support from the State Agency for Research of the Spanish MCIU through the "Center of Excellence Severo Ochoa" award to the Instituto de Astrofísica de Andalucía (SEV-2017-0709), from Spanish project AYA2017-89637-R, and from FEDER. P.S.-S. acknowledges financial support by the Spanish grant AYA-RTI2018-098657-J-I00 "LEO-SBNAF" (MCIU/AEI/FEDER, UE). E. Jehin is a Belgian FNRS Senior Research Associate. R.S. and O.C.W. acknowledge FAPESP grant 2016/24561-0 and CNPq grant 305210/2018-1. T.C.H. acknowledges financial support from the National Research Foundation (NRF; No. 2019R1I1A1A01059609). ; Peer reviewed

The trans-Neptunian objects (TNOs) are small Solar System bodies at large distances from the Sun. As such, their physical properties are difficult tomeasure. Accurate determination of their physical parameters is essential to model and theorize the actual composition and distribution of the population, and to improve our understanding of the formation and evolution of the Solar System. The objective of this work is to construct phase curves in two filters, V and R, of a large TNO sample obtaining absolute magnitudes (H) and phase coefficients (β), and study possible relations between them and other physical parameters (orbital elements, sizes, and albedos).We used our own data, together with data from the literature, to create the phase curves assuming an overall linear trend. We obtained new magnitudes for 28 TNOs, 28 in the V filter and 36 in the R filter. These magnitudes, together with data from the literature, allowed us to obtain absolutes magnitudes, 114 in the V filter and 113 in the R filter, of which 106 have both. From the search for correlations, we found a strong anticorrelation between H - H and Δβ = β - β, which is probably more related to surface structure than to composition or size of the objects. © 2018 The Author(s). ; Based in part on observations collected at the German-Spanish Astronomical Center, Calar Alto, operated jointly by Max-Planck-Institut fur Astronomie and Instituto de Astrofisica de Andalucia (CSIC). Partially based on observations obtained at the Southern Astrophysical Research (SOAR) telescope, which is a joint project of the Ministerio da Ciencia, Tecnologia, Inovacoes e Comunicacoes (MC-TIC) da Republica Federativa do Brasil, the U.S. National Optical Astronomy Observatory (NOAO), the University of North Carolina at Chapel Hill (UNC), and Michigan State University (MSU). CAL acknowledges support from CNPq (141784/2015-6). AAC acknowledges support from CNPq and FAPERJ. Part of the research leading to these results has received funding from the European Union's Horizon 2020 Research and Innovation Programme, under Grant Agreement No. 687378. PSS and JLO would like to acknowledge financial support by the Spanish grant AYA-2014-56637-C2-1-P and the Proyecto de Excelencia de la Junta de Andalucia J.A. 2012-FQM1776.

The study of minor planets is motivated both by fundamental science of Solar system origins (some of these bodies contain the most pristine materials from the early ages of the planetary nebula) and by practical reasons concerning space exploration and impact frequency with Earth. Among minor bodies, near-Earth asteroids are a particularly important group: these objects are nearby the Earth's orbit and they represent both resources and hazards to humans. This is the case of 2014 JO 25. The encounter of this potentially hazardous asteroid with the Earth at 0.011 75 au on 2017 April 19 was a good opportunity to study its properties through photometric and spectral analyses. The work we present here has been carried out thanks to a worldwide observational campaign that included time-series photometry and spectroscopy in the visible and near-infrared wavelengths. The optical images for photometric analysis were collected at different phase angles using small telescopes (<0.5 m) and medium telescopes (from 0.6 to 1.5 m). Spectral analysis was performed by 2-4 m telescopes. The light curve of 2014 JO 25 indicates a synodic rotational period of 4.5286 ± 0.0004 h. Although rotational period had been previously obtained by other authors, this work confirms it with a better accuracy. The obtained reflectance spectrum of this asteroid indicates that it belongs to the S-complex and its surface is most likely composed of a mixture of pyroxenes and olivine. From the comparison of its spectrum to those of meteorite samples, as well as from the wavelength position of the first absorption band (close to 0.9 μm), we suggest that this asteroid might contain a large fraction of low-calcium pyroxene and, tentatively, some amounts of metal.© 2018 The Author(s) Published by Oxford University Press on behalf of the Royal Astronomical Society. ; J. Licandro (JL), M. Serra-Ricart (MSR), O. Vaduvescu (OV), M. Popescu (MP), and J. de Leon (JdL) acknowledge support from the AYA2015-67772-R project (MINECO, Spain). JdL also acknowledges support from from MINECO under the 2015 Severo Ochoa Program SEV-2015-0548. The Isaac Newton Telescope and its service mode are operated on the island of La Palma by the Isaac Newton Group of Telescopes in the Spanish Observatorio del Roque de los Muchachos of the Instituto de Astrofisica de Canarias. The work of MP was also been supported by a grant of the Romanian National Authority for Scientific Research - UEFISCDI, project number PN-II-RU-TE-2014-4-2199. The research leading to these results has received funding from the European Union's Horizon 2020 Research and Innovation Programme, under Grant Agreement No. 687378. We thank E. Molinari for allocation of Director's Discretionary Time at the Telescopio Nazionale Galileo. The work by P. Pravec was supported by the Grant Agency of the Czech Republic, Grant 17-00774S. Observations at CS3 and continued support of the asteroid light-curve data base (LCDB; Warner et al. 2009) are supported by NASA grant 80NSSC18K0851. This paper is partially based on data taken at the 0.77 m La Hita telescope, which is jointly operated by the Instituto de Astrofisica de Andalucia-CSIC and Astrohita. Blue Mountains Observatory is supported by the 2015 Shoemaker NEO grant. ; Peer Reviewed

Context. A group of trans-Neptunian objects (TNOs) are dynamically related to the dwarf planet 136108 Haumea. Ten of them show strong indications of water ice on their surfaces, are assumed to have resulted from a collision, and are accepted as the only known TNO collisional family. Nineteen other dynamically similar objects lack water ice absorptions and are hypothesized to be dynamical interlopers. Aims. We have made observations to determine sizes and geometric albedos of six of the accepted Haumea family members and one dynamical interloper. Ten other dynamical interlopers have been measured by previous works. We compare the individual and statistical properties of the family members and interlopers, examining the size and albedo distributions of both groups. We also examine implications for the total mass of the family and their ejection velocities. Methods. We use far-infrared space-based telescopes to observe the target TNOs near their thermal peak and combine these data with optical magnitudes to derive sizes and albedos using radiometric techniques. Using measured and inferred sizes together with ejection velocities, we determine the power-law slope of ejection velocity as a function of effective diameter. Results. The detected Haumea family members have a diversity of geometric albedos 0.3-0.8, which are higher than geometric albedos of dynamically similar objects without water ice. The median geometric albedo for accepted family members is pV = 0.48-0.18 +0.28, compared to 0.08-0.05 +0.07 for the dynamical interlopers. In the size range D = 175-300 km, the slope of the cumulative size distribution is q = 3.2-0.4 +0.7 for accepted family members, steeper than the q = 2.0 ± 0.6 slope for the dynamical interlopers with D < 500 km. The total mass of Haumea's moons and family members is 2.4% of Haumea's mass. The ejection velocities required to emplace them on their current orbits show a dependence on diameter, with a power-law slope of 0.21-0.50. © ESO 2018. ; Part of this work was supported by the German DLR project number 50 OR 1108. T.M., C.K., P.S., and R.D. acknowledge that the research leading to these results has received funding from the European Union's Horizon 2020 Research and Innovation Programme, under Grant Agreement no 687378. A.P. acknowledges the grant LP2012-31 of the Hungarian Academy of Sciences. N.P. acknowledges funding by the Portuguese FCT - Foundation for Science and Technology (ref: SFRH/BGCT/113686/2015). CITEUC is funded by Portuguese National Funds through FCT - Foundation for Science and Technology (project: UID/Multi/00611/2013) and FEDER - European Regional Development Fund through COMPETE 2020 - Operational Programme Competitiveness and Internationalisation (project: POCI-01-0145-FEDER-006922). C.K. has been supported by the K-125015 and GINOP-2.3.2-15-2016-00003 grants of the National Research, Development and Innovation Office (NKFIH, Hungary).