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1. Optical monitoring of the Didymos-Dimorphos asteroid system with the Danish telescope around the DART mission impact

Author

Rożek, Agata, Snodgrass, Colin, Jørgensen, Uffe G., Pravec, Petr, Bonavita, Mariangela, Rabus, Markus, Khalouei, Elahe, Longa-Peña, Penélope, Burgdorf, Martin J., Donaldson, Abbie, Gardener, Daniel, Crake, Dennis, Sajadian, Sedighe, Bozza, Valerio, Skottfelt, Jesper, Dominik, Martin, Fynbo, J., Hinse, Tobias C., Hundertmark, Markus, Rahvar, Sohrab, Southworth, John, Tregloan-Reed, Jeremy, Kretlow, Mike, Rota, Paolo, Peixinho, Nuno, Andersen, Michael, Amadio, Flavia, Barrios-López, Daniela, and Baeza, Nora Soledad Castillo

Subjects
Astrophysics - Earth and Planetary Astrophysics
Abstract

The NASA's Double-Asteroid Redirection Test (DART) was a unique planetary defence and technology test mission, the first of its kind. The main spacecraft of the DART mission impacted the target asteroid Dimorphos, a small moon orbiting asteroid (65803) Didymos, on 2022 September 26. The impact brought up a mass of ejecta which, together with the direct momentum transfer from the collision, caused an orbital period change of 33 +/- 1 minutes, as measured by ground-based observations. We report here the outcome of the optical monitoring campaign of the Didymos system from the Danish 1.54 m telescope at La Silla around the time of impact. The observations contributed to the determination of the changes in the orbital parameters of the Didymos-Dimorphos system, as reported by arXiv:2303.02077, but in this paper we focus on the ejecta produced by the DART impact. We present photometric measurements from which we remove the contribution from the Didymos-Dimorphos system using a H-G photometric model. Using two photometric apertures we determine the fading rate of the ejecta to be 0.115 +/- 0.003 mag/d (in a 2" aperture) and 0.086 +/- 0.003 mag/d (5") over the first week post-impact. After about 8 days post-impact we note the fading slows down to 0.057 +/- 0.003 mag/d (2" aperture) and 0.068 +/- 0.002 mag/d (5"). We include deep-stacked images of the system to illustrate the ejecta evolution during the first 18 days, noting the emergence of dust tails formed from ejecta pushed in the anti-solar direction, and measuring the extent of the particles ejected sunward to be at least 4000 km., Comment: 20 pages, 6 figures. Accepted for publication in The Planetary Science Journal

Published
2023

3. Optical Monitoring of the Didymos–Dimorphos Asteroid System with the Danish Telescope around the DART Mission Impact

Author

Rożek, Agata, primary, Snodgrass, Colin, additional, Jørgensen, Uffe G., additional, Pravec, Petr, additional, Bonavita, Mariangela, additional, Rabus, Markus, additional, Khalouei, Elahe, additional, Longa-Peña, Penélope, additional, Burgdorf, Martin J., additional, Donaldson, Abbie, additional, Gardener, Daniel, additional, Crake, Dennis, additional, Sajadian, Sedighe, additional, Bozza, Valerio, additional, Skottfelt, Jesper, additional, Dominik, Martin, additional, Fynbo, J., additional, Hinse, Tobias C., additional, Hundertmark, Markus, additional, Rahvar, Sohrab, additional, Southworth, John, additional, Tregloan-Reed, Jeremy, additional, Kretlow, Mike, additional, Rota, Paolo, additional, Peixinho, Nuno, additional, Andersen, Michael, additional, Amadio, Flavia, additional, Barrios-López, Daniela, additional, and Castillo Baeza, Nora Soledad, additional

Published
2023
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4. Physical properties of the trans-Neptunian binary 2000 YW₁₃₄

Author

Vara-Lubiano, Mónica, Fernández-Valenzuela, Estela, Kretlow, Mike, Morales, Nicolas, Benedetti-Rossi, Gustavo, Rommel, Flavia, Ortiz, Jose Luis, Sicardy, Bruno, Santos-Sanz, Pablo, Vieira-Martins, Roberto, Braga-Ribas, Felipe, Camargo, Julio, Kilic, Yucel, Morgado, Bruno, Gomes, Altair, Álvarez-Candal, Álvaro, Lecacheux, Jean, Assafin, Marcelo, Duffard, Rene, Souami, Damya, Desmars, Josselin, Mottola, Stefano, Sota, Alfredo, Pal, Andras, Szakáts, Róbert, Kiss, Csaba, Kalup, Cs., Derekas, Aliz, Zejmo, Michal, Marciniak, Anna, Ogloza, Waldemar, Dangl, Gerhard, Carbognani, Albino, Stirpe, Giovanna, Bruni, Ivan, Csányi, István, Skvar\v, Jure, Mikuz, Herman, Meister, Stefan, Conjat, Matthieu, Ciabattari, Fabrizio, and Krannich, Gregor

Subjects
Trans-Neptunian-Asteroids, Stellar Occultations
Published
2022

5. Book of Abstracts - 41th European Symposium on Occultation Projects (ESOP)

Author

Kretlow, Mike

Subjects
Astronomy, Occultations
Abstract

Book of abstracts of the41th European Symposium on Occultation Projects (ESOP) held inGranada, Spain, 10–11 September 2022. The European Symposium on Occultation Projects is a conference open to both amateur and professionalastronomers and is organized annually by the International Occultation Timing Association / European Section (IOTA/ES).

Published
2022
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6. The Trans-Neptunian Object (19521) Chaos as seen from stellar occultations and photometry observations

Author

Ortiz, Jose, Morales, Nicolas, Vara-Lubiano, Monica, Kretlow, Mike, Sicardy, Bruno, Santos-Sanz, Pablo, Fernandez-Valenzuela, Estela, Braga-Ribas, Felipe, Desmars, Josselin, Duffard, Rene, Camargo, Julio, Souami, Damya, Kilic, Yucel, Rommel, Flavia, Vieira-Martins, Roberto, Assafin, Marcelo, Álvarez-Candal, Álvaro, Morgado, Bruno, Benedetti-Rossi, Guga, Gomes-Junior, Altair, Institut de Mécanique Céleste et de Calcul des Ephémérides (IMCCE), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Lille-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), and Institut Polytechnique des Sciences Avancées (IPSA)

Subjects
[SDU.ASTR]Sciences of the Universe [physics]/Astrophysics [astro-ph]
Abstract

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. *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/

Published
2022

7. Cataloguing astronomical ground-based images of asteroids and TNOs

Author

Morales, Rafael, primary, Morales, Nicolás, additional, Duffard, René, additional, Ortiz, José Luis, additional, Vara-Lubiano, Mónica, additional, Rommel, Flavia, additional, Kretlow, Mike, additional, Santos-Sanz, Pablo, additional, Fernandez-Valenzuela, Estela, additional, Alvarez-Candal, Alvaro, additional, and Robles, Nicolás, additional

Published
2022
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8. Unveiling the Kuiper belt from the JWST through stellar occultations

Author

Santos-Sanz, Pablo, primary, Pinilla-Alonso, Noemí, additional, Stansberry, John, additional, Holler, Bryan J., additional, Gomes Junior, Altair R., additional, Morgado, Bruno E., additional, Ortiz, José Luis, additional, Sicardy, Bruno, additional, Morales, Nicolás, additional, Vara-Lubiano, Mónica, additional, Fernández-Valenzuela, Estela, additional, Desmars, Josselin, additional, Kretlow, Mike, additional, Souami, Damya, additional, Braga-Ribas, Felipe, additional, Camargo, Julio, additional, Benedetti-Rossi, Gustavo, additional, Rommel, Flavia L., additional, Duffard, René, additional, and Assafin, Marcelo, additional

Published
2022
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10. Hi’iaka’s physical and dynamical properties using long-term photometric data

Author

Fernández-Valenzuela, Estela, primary, Ortiz, José Luis, additional, Morales, Nicolás, additional, Jehin, Emmanuel, additional, Burdanov, Artem, additional, de Wit, Julien, additional, Ferrais, Marin, additional, Vara-Lubiano, Mónica, additional, Morales, Rafael, additional, Kretlow, Mike, additional, Santos-Sanz, Pablo, additional, Alvarez-Candal, Alvaro, additional, Duffard, René, additional, Pál, András, additional, Kiss, Csaba, additional, and Szakáts, Róbert, additional

Published
2022
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11. Search for rings around the large Trans-Neptunian Object (50000) Quaoar

Author

Sicardy, Bruno, Morgado, Bruno, Braga-Ribas, Felipe, Ortiz, Jose Luis, Desmars, Josselin, Pereira, Chrystian, Viera-Martins, Roberto, Salo, Heikki, de Santana, Thamiris, Sfair, Rafael, Assafin, Marcelo, Benedetti-Rossi, Gustavo, Camargo, Julio, Fernandez-Valenzuela, Estela, Gomes-Júnior, Altair, Kretlow, Mike, Rommel, Flavia, Santos-Sanz, Pablo, Souami, Damya, Vachier, Frédéric, Institut de Mécanique Céleste et de Calcul des Ephémérides (IMCCE), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Lille-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), and Institut Polytechnique des Sciences Avancées (IPSA)

Subjects
[SDU.ASTR]Sciences of the Universe [physics]/Astrophysics [astro-ph]
Abstract

The Trans-Neptunian Object (50000) Quaoar, classified as a cubewano, is a dwarf planet candidate with a diameter of 1110 km [Br13], semi-major axis of 43.7 au and orbital eccentricity of 0.04. Its satellite Weywot orbits at 13,300 km from the primary object, and from its flux [Fr10], its diameter is about 90 km, assuming the same albedo as Quaoar. Several campaigns were conducted under the umbrella of the Lucky Star project (https://lesia.obspm.fr/lucky-star/) to observe stellar occultations by Quaoar and Weywot. Besides measuring Quaoar's and Weywot's size and shapes, those campaigns aimed at searching for material around Quaoar.Here, we will present the results of our search for rings around Quaoar based on the following observations: Dates Places of observations2 September 2018 Namibia5 June 2019 Canary Islands11 June 2020 Australia, CHEOPS satellite27 August 2021 AustraliaThese campaigns were undertaken in a context where rings are already known to exists around other small bodies of the solar system: the Centaur object Chariklo [Br14] and the dwarf planet Haumea [Or17]. These two ring systems, in spite of large differences in sizes and heliocentric distances, both orbit close to the 1/3 Spin-Orbit Resonance (SOR) with the central body [Or17,Le17], meaning that the latter completes three rotations while a ring particle completes one orbital revolution. Because of their non-axisymmetric shapes, and contrarily to giant planets, Chariklo and Haumea induce strong SORs [Si19]. Theoretical calculations [Si21] and numerical simulations of collisional disks [Sa21] show that the 1/3 SOR is indeed a possible cause of confinement of a narrow ring.If ring exists at the Quaoar 1/3 SOR, it should be close to an orbital radius of 4,200 km. This represents 7.5 Quaoar's radii, well outside the Roche limit of the central body. So, if a dense ring were to be confined near this resonance, it is expected to accrete into a satellite, and thus disappear over a short time scale. We will discuss models that could maintain a colliding disk near the Quaoar 1/3 SOR in spite of this obstacle.Acknowledgments. 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 no. 669416 "Lucky Star"[Br13] Braga-Ribas et al., ApJ 773, 26 (2013)[Fr10] Fraser and Brown, ApJ, 714, 1547 (2010)[Le17] Leiva et al., Astron. J. 154, 159 (2017)[Or17] Ortiz et al., Nature 550, 219 (2017)[Sa21] Salo, H. et al., European Planetary Science Congress, EPSC2021-338 (2021)[Si19] Sicardy, B. et al., Nature Astronomy 3, 146 (2019)[Si21] Sicardy, B. et al., European Planetary Science Congress, EPSC2021-91 (2021)

Published
2022

13. Constraints on the structure and seasonal variations of Triton's atmosphere from the 5 October 2017 stellar occultation and previous observations

Author

Física aplicada I, Fisika aplikatua I, Marques Oliveira, Joana, Sicardy, Bruno, Gómes Junior, A.R., Ortiz, J.L., Strobel, D.F., Bertrand, T., Forget, F., Lellouch, E., Desmars, J., Bérard, D., Doressoundiram, A., Lecacheux, J., Leiva, R., Meza, E., Roques, F., Souami, D., Widemann, T., Santos Sanz, Pablo, Morales, N., Duffard, Rene, Fernández Valenzuela, Estela, Castro Tirado, A.J., Braga Ribas, Felipe, Morgado, Bruno, Assafin, Marcelo, Bueno de Camargo, Julio Ignacio, Vieira Martins, Roberto, Benedetti Rossi, Gustavo, Santos Filho, S., Banda Huarca, M.V., Quispe Huaynasi, F., Pereira, Chrystian Luciano, Rommel, Flavia Luane, Margoti, Giuliano, Dias Oliveira, A., Colas, F., Berthier, J., Renner, S., Hueso, Ricardo, Pérez Hoyos, Santiago, Sánchez Lavega, Agustín María, Rojas Palenzuela, José Félix, Beisker, W., Kretlow, Mike, Herald, D., Gault, D., Bath, K.-L., Bode, H.-J., Bredner, E., Guhl, K., Haymes, T.V., Hummel, E., Kattentidt, B., Klös, O., Pratt, A., Thome, B., Avdellidou, Chrysa, Gazeas, K., Karampotsiou, E., Tzouganatos, L., Kardasis, E., Christou, A.A., Xilouris, Emmanuel, Alikakos, I., Gourzelas, A., Liakos, Alexios, Charmandaris, Vassilis, Jelínek, Martin, Štrobl, Jan, Eberle, A., Rapp, K., Gährken, B., Klemt, B., Kowollik, S., Bitzer, R., Miller, M., Herzogenrath, G., Frangenberg, Dirk, Brandis, L., Pütz, I., Perdelwitz, Volker, Piehler, G. M., Riepe, P., von Poschinger, K., Baruffetti, P., Cenadelli, D., Christille, J.-M., Ciabattari, F., Di Luca, R., Alboresi, D., Leto, Giuseppe, Zanmar Sánchez, R., Bruno, P., Occhipinti, G., Morrone, L., Cupolino, L., Noschese, A., Vecchione, A., Scalia, Cesare, Lo Savio, R., Giardina, G., Kamoun, S., Barbosa, R., Behrend, R., Spano, M., Bouchet, E., Cottier, M., Falco, L., G. Gallego, Sofía, Tortorelli, Luca, Sposetti, S., Sussenbach, J., Van Den Abbeel, F., André, P., Llibre, M., Pailler, Frédéric, Ardissone, J., Boutet, Michel, Sánchez, J., Bretton, M., Cailleau, A., Pic, V., Granier, L., Chauvet, R., Conjat, M., Dauvergne, J.L., Dechambre, O., Delay, P., Delcroix, Marc, Rousselot, Lionel, Ferreira, João, Machado, Pedro, Tanga, P., Rivet, J.-P., Frappa, Eric, Irzyk, M., Jabet, F., Kaschinski, M., Klotz, A., Rieugnie, Y., Klotz, A.N., Labrevoir, O., Lavandier, D., Walliang, D., Leroy, A., Bouley, S., Lisciandra, S., Coliac, Jean-François, Metz, F., Erpelding, D., Nougayrede, Jean-Philippe, Midavaine, T., Miniou, M., Moindrot, S., Morel, P., Reginato, B., Reginato, E., Rudelle, J., Tregon, B., Tanguy, R., David, J., Thuillot, W., Hestroffer, D., Vaudescal, G., Baba Aissa, D., Grigahcene, Z., Briggs, D., Broadbent, Stephen, Denyer, P., Haigh, Nicholas, Quinn, N., Thurston, G., Fossey, S. J., Arena, C., Jennings, M., talbot, J., Alonso Burgos, Sergio, Román Reche, A., Casanova, V., Briggs, E., Iglesias Marzoa, Ramón, Abril Ibáñez, J., Díaz Martín, M.C., González, H., Maestre García, J.L., Marchant, Jonathan, Ordoñez Etxeberria, Iñaki, Martorell, P., Salamero, J., Organero, F., Ana, L., Fonseca, F., Peris, V., Brevia, O., Selva, A., Perelló Pérez, Carlos, Cabedo, V., Gonçalves, Rui M. D., Ferreira, M., Marques Dias, Filipe, Daassou, A., Barkaoui, Khalid, Benkhaldoun, Z., Guennoun, M., Chouqar, J., Jehin, E., Rinner, C., Lloyd, J., El Moutamid, Maryame, Lamarche, C., Pollock, J.T., caton, D.B., Kouprianov, Vladimir, Timerson, B.W., Blanchard, G., Payet, B., Peyrot, A., Teng-Chuen-Yu, J.-P., Françoise, J., Mondon, Bernard, Payet, Thierry, Boissel, C., Castets, M., Hubbard, William, Hill, R., Reitsema, H. J., Mousis, Olivier, Ball, L., Neilsen, G., Hutcheon, S., lay, K., Anderson, P., Moy, M., Jonsen, M., Pink, I., Walters, R., Downs, B., Física aplicada I, Fisika aplikatua I, Marques Oliveira, Joana, Sicardy, Bruno, Gómes Junior, A.R., Ortiz, J.L., Strobel, D.F., Bertrand, T., Forget, F., Lellouch, E., Desmars, J., Bérard, D., Doressoundiram, A., Lecacheux, J., Leiva, R., Meza, E., Roques, F., Souami, D., Widemann, T., Santos Sanz, Pablo, Morales, N., Duffard, Rene, Fernández Valenzuela, Estela, Castro Tirado, A.J., Braga Ribas, Felipe, Morgado, Bruno, Assafin, Marcelo, Bueno de Camargo, Julio Ignacio, Vieira Martins, Roberto, Benedetti Rossi, Gustavo, Santos Filho, S., Banda Huarca, M.V., Quispe Huaynasi, F., Pereira, Chrystian Luciano, Rommel, Flavia Luane, Margoti, Giuliano, Dias Oliveira, A., Colas, F., Berthier, J., Renner, S., Hueso, Ricardo, Pérez Hoyos, Santiago, Sánchez Lavega, Agustín María, Rojas Palenzuela, José Félix, Beisker, W., Kretlow, Mike, Herald, D., Gault, D., Bath, K.-L., Bode, H.-J., Bredner, E., Guhl, K., Haymes, T.V., Hummel, E., Kattentidt, B., Klös, O., Pratt, A., Thome, B., Avdellidou, Chrysa, Gazeas, K., Karampotsiou, E., Tzouganatos, L., Kardasis, E., Christou, A.A., Xilouris, Emmanuel, Alikakos, I., Gourzelas, A., Liakos, Alexios, Charmandaris, Vassilis, Jelínek, Martin, Štrobl, Jan, Eberle, A., Rapp, K., Gährken, B., Klemt, B., Kowollik, S., Bitzer, R., Miller, M., Herzogenrath, G., Frangenberg, Dirk, Brandis, L., Pütz, I., Perdelwitz, Volker, Piehler, G. M., Riepe, P., von Poschinger, K., Baruffetti, P., Cenadelli, D., Christille, J.-M., Ciabattari, F., Di Luca, R., Alboresi, D., Leto, Giuseppe, Zanmar Sánchez, R., Bruno, P., Occhipinti, G., Morrone, L., Cupolino, L., Noschese, A., Vecchione, A., Scalia, Cesare, Lo Savio, R., Giardina, G., Kamoun, S., Barbosa, R., Behrend, R., Spano, M., Bouchet, E., Cottier, M., Falco, L., G. Gallego, Sofía, Tortorelli, Luca, Sposetti, S., Sussenbach, J., Van Den Abbeel, F., André, P., Llibre, M., Pailler, Frédéric, Ardissone, J., Boutet, Michel, Sánchez, J., Bretton, M., Cailleau, A., Pic, V., Granier, L., Chauvet, R., Conjat, M., Dauvergne, J.L., Dechambre, O., Delay, P., Delcroix, Marc, Rousselot, Lionel, Ferreira, João, Machado, Pedro, Tanga, P., Rivet, J.-P., Frappa, Eric, Irzyk, M., Jabet, F., Kaschinski, M., Klotz, A., Rieugnie, Y., Klotz, A.N., Labrevoir, O., Lavandier, D., Walliang, D., Leroy, A., Bouley, S., Lisciandra, S., Coliac, Jean-François, Metz, F., Erpelding, D., Nougayrede, Jean-Philippe, Midavaine, T., Miniou, M., Moindrot, S., Morel, P., Reginato, B., Reginato, E., Rudelle, J., Tregon, B., Tanguy, R., David, J., Thuillot, W., Hestroffer, D., Vaudescal, G., Baba Aissa, D., Grigahcene, Z., Briggs, D., Broadbent, Stephen, Denyer, P., Haigh, Nicholas, Quinn, N., Thurston, G., Fossey, S. J., Arena, C., Jennings, M., talbot, J., Alonso Burgos, Sergio, Román Reche, A., Casanova, V., Briggs, E., Iglesias Marzoa, Ramón, Abril Ibáñez, J., Díaz Martín, M.C., González, H., Maestre García, J.L., Marchant, Jonathan, Ordoñez Etxeberria, Iñaki, Martorell, P., Salamero, J., Organero, F., Ana, L., Fonseca, F., Peris, V., Brevia, O., Selva, A., Perelló Pérez, Carlos, Cabedo, V., Gonçalves, Rui M. D., Ferreira, M., Marques Dias, Filipe, Daassou, A., Barkaoui, Khalid, Benkhaldoun, Z., Guennoun, M., Chouqar, J., Jehin, E., Rinner, C., Lloyd, J., El Moutamid, Maryame, Lamarche, C., Pollock, J.T., caton, D.B., Kouprianov, Vladimir, Timerson, B.W., Blanchard, G., Payet, B., Peyrot, A., Teng-Chuen-Yu, J.-P., Françoise, J., Mondon, Bernard, Payet, Thierry, Boissel, C., Castets, M., Hubbard, William, Hill, R., Reitsema, H. J., Mousis, Olivier, Ball, L., Neilsen, G., Hutcheon, S., lay, K., Anderson, P., Moy, M., Jonsen, M., Pink, I., Walters, R., and Downs, B.

Abstract

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.

Published
2022

15. Pluto's Atmospheric Activity, Ephemeris Offset and Satellite Detections from Observations in 2007

Author

Sicardy, Bruno, Widemann, Thomas, Colas, François, Doressoundiram, Alain, Lecacheux, Jean, Vachier, Frédéric, Beisker, Wolfgang, Assafin, Marcelo, Camargo, J. I. B., da Silva Neto, D. N., Ribas, F. B., Andrei, A., Vieira Martins, Roberto, Behrend, Raoul, Hubbard, W. E., Larson, S., Marchis, Franck, Wong, Michael H., Severson, S., Dunham, David W., Warner, Brian D., Peterson, C., Molnar, L., George, T., Maley, Paul, Coziol, R., Choi, Y., Bath, Karl Ludwig, Kretlow, Mike, Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), Pôle Planétologie du LESIA, Laboratoire d'études spatiales et d'instrumentation en astrophysique = Laboratory of Space Studies and Instrumentation in Astrophysics (LESIA), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité), Institut de Mécanique Céleste et de Calcul des Ephémérides (IMCCE), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Lille-Centre National de la Recherche Scientifique (CNRS), Groupe Astrométrie et Planétologie (GAP), and Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Lille-Centre National de la Recherche Scientifique (CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris

Subjects
[PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph]
Abstract

International audience

Published
2007

16. Les occultations stellaires par Titan, Pluton, Charton et Titania

Author

Sicardy, Bruno, Widemann, Thomas, Bellucci, Aurélie, Lecacheux, Alain, Lellouch, Emmanuel, Roques, Françoise, Colas, François, Beisker, Wolfgang, Kretlow, Mike, Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), Physique des plasmas, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Pôle Planétologie du LESIA, Laboratoire d'études spatiales et d'instrumentation en astrophysique = Laboratory of Space Studies and Instrumentation in Astrophysics (LESIA), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, and Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité)

Subjects
[PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph]
Abstract

National audience

Published
2006

17. The two stellar occultations of November 14, 2003: revealing Titan's stratosphere at sub-km resolution

Author

Sicardy, Bruno, Colas, François, Widemann, Thomas, Fienga, Agnès, Lacour, Sylvestre, Lecacheux, Jean, Lellouch, Emmanuel, Pau, Sylvain, Renner, Stefan, Roques, Françoise, Glass, Ian S., Baba, D., Nagata, Tetsuya, Ferri, Francesca, Martinez, C., Beisker, Wolfgang, Enke, S., Bath, Karl Ludwig, Bode, F., Bode, H.-J., Fiel, D., Kretlow, Mike, Hernandez, M., Horns, D., Luedemann, J., Luedemann, H., Tegtmeier, A., Dewitt, Curtis N., Fraser, B., Jones, T., Shonau, P., Turk, C., Meintjies, P., Howell, R. R., Kidger, Mark R., Ortiz, José Luiz, Rosenzweig, P., Naranjo, O., Rapaport, M., Observatoire de Paris, Université Paris sciences et lettres (PSL), Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), Pôle Astronomie du LESIA, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Ingénieurs, Techniciens et Administratifs, Pôle Planétologie du LESIA, Laboratoire d'études spatiales et d'instrumentation en astrophysique = Laboratory of Space Studies and Instrumentation in Astrophysics (LESIA), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité), South African Astronomical Observatory (SAAO), Nagoya University, Università degli Studi di Padova = University of Padua (Unipd), Facultad Regional Buenos Aires, Universidad Tecnológica Nacional, International Occultation Timing Association, European Section (IOTA/ES), South African Weather Service, Boyden Observatory, University of the Free State, WIRO, IAC Tenerife, IAA Granada, and Universidad Central de Venezuela (UCV)

Subjects
[PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph]
Abstract

International audience; On November 14, 2003, Titan occulted two bright Tycho stars (V= 8.4 and V= 10.3). The first event was observed in the Indian Ocean and southern Africa, while the second one was followed from western Europe, northern and central Americas. Data were gathered by both professional and amateur astronomers, using fixed and portable telescopes at wavelengths ranging from visible to near IR (K band).

Published
2004

18. Changes in Pluto's Atmosphere Revealed by Occultations

Author

Sicardy, Bruno, Widemann, Thomas, Lellouch, Emmanuel, Veillet, Christian, Colas, François, Roques, Françoise, Beisker, Wolfgang, Kretlow, Mike, Cuillandre, Jean-Charles, Hainaut, Olivier, Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), Pôle Planétologie du LESIA, Laboratoire d'études spatiales et d'instrumentation en astrophysique = Laboratory of Space Studies and Instrumentation in Astrophysics (LESIA), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, and Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité)

Subjects
[PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph]
Abstract

International audience

Published
2003

19. The 20 July 2002 occultation of P126 by Pluto

Author

Sicardy, Bruno, Colas, François, Widemann, Thomas, Beisker, Wolfgang, Birnbaum, C., Brooks, K., Delsanti, Audrey, Fienga, Agnès, Gendron, Éric, Hainaut, Olivier, Kretlow, Mike, Lagrange, Anne-Marie, Lecacheux, Jean, Leyrat, Cédric, Maury, Alain, Raynaud, Elisabeth, Rapaport, M., Renner, Stefan, Roques, Françoise, Schultheis, Mathias, Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), Pôle Astronomie du LESIA, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Pôle Planétologie du LESIA, Laboratoire d'études spatiales et d'instrumentation en astrophysique = Laboratory of Space Studies and Instrumentation in Astrophysics (LESIA), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, and Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité)

Subjects
[PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph]
Abstract

International audience

Published
2002

20. Large Changes in Pluto’s Atmosphere Revealed by Stellar Occultations

Author

Sicardy, Bruno, primary, Widemann, Thomas, additional, Lellouch, Emmanuel, additional, Roques, Françoise, additional, Gendron, Eric, additional, Veillet, Christian, additional, Cuillandre, Jean-Charles, additional, Colas, François, additional, Beisker, Wolfgang, additional, Kretlow, Mike, additional, Hainaut, Olivier R., additional, and Lidman, Chris, additional

Published
2005
Full Text
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22. Optical Monitoring of the Didymos–Dimorphos Asteroid System with the Danish Telescope around the DART Mission Impact

Author

Rożek, Agata, Snodgrass, Colin, Jørgensen, Uffe G., Pravec, Petr, Bonavita, Mariangela, Rabus, Markus, Khalouei, Elahe, Longa-Peña, Penélope, Burgdorf, Martin J., Donaldson, Abbie, Gardener, Daniel, Crake, Dennis, Sajadian, Sedighe, Bozza, Valerio, Skottfelt, Jesper, Dominik, Martin, Fynbo, J., Hinse, Tobias C., Hundertmark, Markus, Rahvar, Sohrab, Southworth, John, Tregloan-Reed, Jeremy, Kretlow, Mike, Rota, Paolo, Peixinho, Nuno, Andersen, Michael, Amadio, Flavia, Barrios-López, Daniela, Castillo Baeza, Nora Soledad, Rożek, Agata, Snodgrass, Colin, Jørgensen, Uffe G., Pravec, Petr, Bonavita, Mariangela, Rabus, Markus, Khalouei, Elahe, Longa-Peña, Penélope, Burgdorf, Martin J., Donaldson, Abbie, Gardener, Daniel, Crake, Dennis, Sajadian, Sedighe, Bozza, Valerio, Skottfelt, Jesper, Dominik, Martin, Fynbo, J., Hinse, Tobias C., Hundertmark, Markus, Rahvar, Sohrab, Southworth, John, Tregloan-Reed, Jeremy, Kretlow, Mike, Rota, Paolo, Peixinho, Nuno, Andersen, Michael, Amadio, Flavia, Barrios-López, Daniela, and Castillo Baeza, Nora Soledad

Abstract

The NASA’s Double-Asteroid Redirection Test (DART) was a unique planetary defence and technology test mission, the first of its kind. The main spacecraft of the DART mission impacted the target asteroid Dimorphos, a small moon orbiting the asteroid Didymos (65803), on 2022 September 26. The impact brought up a mass of ejecta which, together with the direct momentum transfer from the collision, caused an orbital period change of 33 ± 1 minutes, as measured by ground-based observations. We report here the outcome of the optical monitoring campaign of the Didymos system from the Danish 1.54 m telescope at La Silla around the time of impact. The observations contributed to the determination of the changes in the orbital parameters of the Didymos–Dimorphos system, as reported by Thomas et al., but in this paper we focus on the ejecta produced by the DART impact. We present photometric measurements from which we remove the contribution from the Didymos–Dimorphos system using an H–G photometric model. Using two photometric apertures we determine the fading rate of the ejecta to be 0.115 ± 0.003 mag day−1 (in a 2″ aperture) and 0.086 ± 0.003 mag day−1 (5″) over the first week postimpact. After about 8 days postimpact we note the fading slows down to 0.057 ± 0.003 mag day−1 (2″ aperture) and 0.068 ± 0.002 mag day−1 (5″). We include deep-stacked images of the system to illustrate the ejecta evolution during the first 18 days, noting the emergence of dust tails formed from ejecta pushed in the antisolar direction, and measuring the extent of the particles ejected Sunward to be at least 4000 km.

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