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Context. First identified in 2016 by the Japan Aerospace eXploration Agency (JAXA) Akatsuki mission, the discontinuity or disruption is a recurrent wave observed to propagate over decades at the deeper clouds of Venus (47–56 km above the surface), while its absence at the top of the clouds (∼70 km) suggests that it dissipates at the upper clouds and contributes to the maintenance of the puzzling atmospheric superrotation of Venus through wave-mean flow interaction. Aims. Taking advantage of the campaign of ground-based observations undertaken in coordination with the Akatsuki mission from December 2021 until July 2022, we undertook the longest uninterrupted monitoring of the cloud discontinuity to date to obtain a pioneering long-term characterisation of its main properties and to better constrain its recurrence and lifetime. Methods. The dayside upper, middle, and nightside lower clouds were studied with images acquired by the Akatsuki Ultraviolet Imager (UVI), amateur observers, and SpeX at the NASA Infrared Telescope Facility (IRTF). Hundreds of images were inspected in search of the discontinuity events and to measure key properties such as its dimensions, orientation, and rotation period. Results. We succeeded in tracking the discontinuity at the middle clouds during 109 days without interruption. The discontinuity exhibited properties nearly identical to measurements in 2016 and 2020, with an orientation of 91° ±8°, length of 4100 ± 800 km, width of 500 ± 100 km, and a rotation period of 5.11 ± 0.09 days. Ultraviolet images during 13–14 June 2022 suggest that the discontinuity may have manifested at the top of the clouds during ∼21 h as a result of an altitude change in the critical level for this wave, due to slower zonal winds. J.P. thanks EMERGIA funding from Junta de Andalucía in Spain (code: EMERGIA20_00414). I.G.-L. and A.S.-L. were supported by Grant PID2019-109467GB-I00 funded by MCIN/AEI/10.13039/501100011033/ and by Grupos 1128 Gobierno Vasco IT1742-22. We thank the members of JAXA’s Akatsuki mission and Visiting Astronomers at the Infrared Telescope Facility operated by the University of Hawaii under contract 80HQTR19D0030 with NASA. This research would have been impossible without the many amateur observers who observed Venus intensively during the investigated period and shared their images, although we would like to highlight contributions from M. A. Bianchi, G. Calapai, D. Kananovich, N. MacNeill, V. Mirabella, W. M. Lonsdale, R. Sedrani, L. S. Viola and G. Z. Wang.

J.M.O. acknowledges financial support from the Portuguese Foundation for Science and Technology (FCT) and the European Social Fund (ESF) through the PhD grant SFRH/BD/131700/2017. The work leading to these results has received funding from the European Research Council under the European Community's H2020 2014-2021 ERC grant Agreement nffi 669416 "Lucky Star". We thank S. Para who supported some travels to observe the 5 October 2017 occultation. T.B. was supported for this research by an appointment to the National Aeronautics and Space Administration (NASA) Post-Doctoral Program at the Ames Research Center administered by Universities Space Research Association (USRA) through a contract with NASA. We acknowledge useful exchanges with Mark Gurwell on the ALMA CO observations. 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. J.L.O., P.S.-S., N.M. and R.D. 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 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. 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). P.S.-S. acknowledges financial support by the Spanish grant AYA-RTI2018-098657-J-I00 "LEO-SBNAF". The work was partially based on observations made at the Laboratorio Nacional de Astrofisica (LNA), Itajuba-MG, Brazil. The following authors acknowledge the respective CNPq grants: F.B.-R. 309578/2017-5; R.V.-M. 304544/2017-5, 401903/2016-8; J.I.B.C. 308150/2016-3 and 305917/2019-6; M.A. 427700/20183, 310683/2017-3, 473002/2013-2. This study was financed in part by the Coordenacao de Aperfeicoamento 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). G.B.R. acknowledges CAPES-FAPERJ/PAPDRJ grant E26/203.173/2016 and CAPES-PRINT/UNESP grant 88887.571156/2020-00, M.A. FAPERJ grant E26/111.488/2013 and A.R.G.Jr. FAPESP grant 2018/11239-8. B.E.M. thanks CNPq 150612/2020-6 and CAPES/Cofecub-394/2016-05 grants. Part of the photometric data used in this study were collected in the frame of the photometric observations with the robotic and remotely controlled telescope at the University of Athens Observatory (UOAO; Gazeas 2016). The 2.3 m Aristarchos telescope is operated on Helmos Observatory by the Institute for Astronomy, Astrophysics, Space Applications and Remote Sensing of the National Observatory of Athens. Observations with the 2.3 m Aristarchos telescope were carried out under OPTICON programme. This project has received funding from the European Union's Horizon 2020 research and innovation programme under grant agreement No 730890. This material reflects only the authors views and the Commission is not liable for any use that may be made of the information contained therein. The 1. 2m Kryoneri telescope is operated by the Institute for Astronomy, Astrophysics, Space Applications and Remote Sensing of the National Observatory of Athens. The Astronomical Observatory of the Autonomous Region of the Aosta Valley (OAVdA) is managed by the Fondazione Clement Fillietroz-ONLUS, which is supported by the Regional Government of the Aosta Valley, the Town Municipality of Nus and the "Unite des Communes valdotaines Mont-Emilius". The 0.81 m Main Telescope at the OAVdA was upgraded thanks to a Shoemaker NEO Grant 2013 from The Planetary Society. D.C. and J.M.C. acknowledge funds from a 2017 'Research and Education' grant from Fondazione CRT-Cassa di Risparmio di Torino. P.M. acknowledges support from the Portuguese Fundacao para a Ciencia e a Tecnologia ref. PTDC/FISAST/29942/2017 through national funds and by FEDER through COMPETE 2020 (ref. POCI010145 FEDER007672). F.J. acknowledges Jean Luc Plouvier for his help. S.J.F. and C.A. would like to thank the UCL student support observers: Helen Dai, Elise Darragh-Ford, Ross Dobson, Max Hipperson, Edward Kerr-Dineen, Isaac Langley, Emese Meder, Roman Gerasimov, Javier Sanjuan, and Manasvee Saraf. We are grateful to the CAHA, OSN and La Hita Observatory staffs. This research is partially based on observations collected at Centro Astronomico HispanoAleman (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 Liverpool John Moores University in the Spanish Observatorio del Roque de los Muchachos of the Instituto de Astrofisica de Canarias with financial support from the UK Science and Technology Facilities Council. Partially based on observations made with the Tx40 and Excalibur telescopes 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 Aragon (CEFCA). Tx40 and Excalibur are funded with the Fondos de Inversiones de Teruel (FITE). A.R.R. would like to thank Gustavo Roman for the mechanical adaptation of the camera to the telescope to allow for the observation to be recorded. R.H., J.F.R., S.P.H. and A.S.L. have been supported by the Spanish projects AYA2015-65041P and PID2019-109467GB-100 (MINECO/FEDER, UE) and Grupos Gobierno Vasco IT1366-19. Our great thanks to Omar Hila and their collaborators in Atlas Golf Marrakech Observatory for providing access to the T60cm telescope. TRAPPIST is a project funded by the Belgian Fonds (National) de la Recherche Scientifique (F.R.S.-FNRS) under grant PDR T.0120.21. TRAPPIST-North is a project funded by the University of Liege, and performed in collaboration with Cadi Ayyad University of Marrakesh. E.J. is a FNRS Senior Research Associate., Context. A stellar occultation by Neptune's main satellite, Triton, was observed on 5 October 2017 from Europe, North Africa, and the USA. We derived 90 light curves from this event, 42 of which yielded a central flash detection. Aims. We aimed at constraining Triton's atmospheric structure and the seasonal variations of its atmospheric pressure since the Voyager 2 epoch (1989). We also derived the shape of the lower atmosphere from central flash analysis. Methods. We used Abel inversions and direct ray-tracing code to provide the density, pressure, and temperature profiles in the altitude range similar to 8 km to similar to 190 km, corresponding to pressure levels from 9 mu bar down to a few nanobars. Results. (i) A pressure of 1.18 +/- 0.03 mu bar is found at a reference radius of 1400 km (47 km altitude). (ii) A new analysis of the Voyager 2 radio science occultation shows that this is consistent with an extrapolation of pressure down to the surface pressure obtained in 1989. (iii) A survey of occultations obtained between 1989 and 2017 suggests that an enhancement in surface pressure as reported during the 1990s might be real, but debatable, due to very few high S/N light curves and data accessible for reanalysis. The volatile transport model analysed supports a moderate increase in surface pressure, with a maximum value around 2005-2015 no higher than 23 mu bar. The pressures observed in 1995-1997 and 2017 appear mutually inconsistent with the volatile transport model presented here. (iv) The central flash structure does not show evidence of an atmospheric distortion. We find an upper limit of 0.0011 for the apparent oblateness of the atmosphere near the 8 km altitude., Portuguese Foundation for Science and Technology SFRH/BD/131700/2017, European Social Fund (ESF) SFRH/BD/131700/2017, European Research Council under the European Community's H2020 2014-2021 ERC grant 669416, Spanish Government SEV-2017-0709 AYA-2017-84637-R AYA-RTI2018-098657-J-I00, Junta de Andalucia 2012-FQM1776, European Union's Horizon 2020 Research and Innovation Programme, as part of the project "Small Bodies Near and Far" (SBNAF) 687378, Conselho Nacional de Desenvolvimento Cientifico e Tecnologico (CNPQ), Fundacao de Apoio a Pesquisa do Distrito Federal (FAPDF) 309578/2017-5 304544/2017-5 401903/2016-8 308150/2016-3 305917/2019-6 427700/2018-3 310683/2017-3 473002/2013-2, Coordenacao de Aperfeicoamento de Pessoal de Nivel Superior (CAPES) 001, Conselho Nacional de Desenvolvimento Cientifico e Tecnologico (CNPQ) 465376/2014-2 CAPES-FAPERJ/PAPDRJ grant E26/203.173/2016 CAPES-PRINT/UNESP grant 88887.571156/2020-00, Fundacao Carlos Chagas Filho de Amparo a Pesquisa do Estado do Rio De Janeiro (FAPERJ) E26/111.488/2013, Fundacao de Amparo a Pesquisa do Estado de Sao Paulo (FAPESP) 2018/11239-8, Conselho Nacional de Desenvolvimento Cientifico e Tecnologico (CNPQ) 150612/2020-6, European Union's Horizon 2020 research and innovation programme 730890, Regional Government of the Aosta Valley, Town Municipality of Nus, Unite des Communes valdotaines Mont-Emilius, Planetary Society, Fondazione CRT-Cassa di Risparmio di Torino, Portuguese Foundation for Science and Technology PTDC/FISAST/29942/2017, FEDER through COMPETE 2020 POCI010145 FEDER007672, UK Research & Innovation (UKRI), Science & Technology Facilities Council (STFC), Fondos de Inversiones de Teruel (FITE), Spanish Government AYA2015-65041P PID2019-109467GB-100, Grupos Gobierno Vasco IT1366-19, Fonds de la Recherche Scientifique - FNRS PDR T.0120.21, University of Liege, CAPES/Cofecub-394/2016-05

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 (P3) 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.