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1. The multichord stellar occultation by the centaur Bienor on January 11, 2019

Author

Fernández-Valenzuela, E., Morales, N., Vara-Lubiano, M., Ortiz, J. L., Benedetti-Rossi, G., Sicardy, B., Kretlow, M., Santos-Sanz, P., Morgado, B., Souami, D., Organero, F., Ana, L., Fonseca, F., Román, A., Alonso, S., Gonçalves, R., Ferreira, M., Iglesias-Marzoa, R., Lamadrid, J. L., Alvarez-Candal, A., Assafin, M., Braga-Ribas, F., Camargo, J. I. B., Colas, F., Desmars, J., Duffard, R., Lecacheux, J., Gomes-Júnior, A. R., Rommel, F. L., Vieira-Martins, R., Pereira, C. L., Casanova, V., Selva, A., Perelló, C., Mottola, S., Hellmich, S., Maestre, J. L., Castro-Tirado, A. J., Pal, A., Trigo-Rodriguez, J. M., Beisker, W., Laporta, A., Garcés, M., Escaned, L., and Bretton, M.

Subjects
Astrophysics - Earth and Planetary Astrophysics
Abstract

Within our program of physical characterization of trans-Neptunian objects and centaurs, we predicted a stellar occultation by the centaur (54598) Bienor to occur on January 11, 2019, with good observability potential. We obtained high accuracy astrometric data to refine the prediction, resulting in a shadow path favorable for the Iberian Peninsula. This encouraged us to carry out an occultation observation campaign that resulted in five positive detections from four observing sites. This is the fourth centaur for which a multichord (more than two chords) stellar occultation has been observed so far, the other three being (2060) Chiron, (10199) Chariklo, and (95626) 2002 GZ$_{32}$. From the analysis of the occultation chords, combined with the rotational light curve obtained shortly after the occultation, we determined that Bienor has an area-equivalent diameter of $150\pm20$ km. This diameter is $\sim30$ km smaller than the one obtained from thermal measurements. The position angle of the short axis of the best fitting ellipse obtained through the analysis of the stellar occultation does not match that of the spin axis derived from long-term photometric models. We also detected a strong irregularity in one of the minima of the rotational light curve that is present no matter the aspect angle at which the observations were done. We present different scenarios to reconcile the results from the different techniques. We did not detect secondary drops related to potential rings or satellites. Nonetheless, similar rings in size to that of Chariklo's cannot be discarded due to low data accuracy., Comment: Accepted for publication in A\&A

Published
2022
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2. Constraints on the structure and seasonal variations of Triton's atmosphere from the 5 October 2017 stellar occultation and previous observations

Author

Oliveira, J. Marques, Sicardy, B., Gomes-Júnior, 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, P., Morales, N., Duffard, R., Fernández-Valenzuela, E., Castro-Tirado, A. J., Braga-Ribas, F., Morgado, B. E., Assafin, M., Camargo, J. I. B., Vieira-Martins, R., Benedetti-Rossi, G., Santos-Filho, S., Banda-Huarca, M. V., Quispe-Huaynasi, F., Pereira, C. L., Rommel, F. L., Margoti, G., Dias-Oliveira, A., Colas, F., Berthier, J., Renner, S., Hueso, R., Pérez-Hoyos, S., Sánchez-Lavega, A., Rojas, J. F., Beisker, W., Kretlow, M., 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, C., Gazeas, K., Karampotsiou, E., Tzouganatos, L., Kardasis, E., Christou, A. A., Xilouris, E. M., Alikakos, I., Gourzelas, A., Liakos, A., Charmandaris, V., Jelínek, M., Štrobl, J., Eberle, A., Rapp, K., Gährken, B., Klemt, B., Kowollik, S., Bitzer, R., Miller, M., Herzogenrath, G., Frangenberg, D., Brandis, L., Pütz, I., Perdelwitz, V., Piehler, G. M., Riepe, P., von Poschinger, K., Baruffetti, P., Cenadelli, D., Christille, J. -M., Ciabattari, F., Di Luca, R., Alboresi, D., Leto, G., Sanchez, R. Zanmar, Bruno, P., Occhipinti, G., Morrone, L., Cupolino, L., Noschese, A., Vecchione, A., Scalia, C., Savio, R. Lo, Giardina, G., Kamoun, S., Barbosa, R., Behrend, R., Spano, M., Bouchet, E., Cottier, M., Falco, L., Gallego, S., Tortorelli, L., Sposetti, S., Sussenbach, J., Abbeel, F. Van Den, André, P., Llibre, M., Pailler, F., Ardissone, J., Boutet, M., Sanchez, J., Bretton, M., Cailleau, A., Pic, V., Granier, L., Chauvet, R., Conjat, M., Dauvergne, J. L., Dechambre, O., Delay, P., Delcroix, M., Rousselot, L., Ferreira, J., Machado, P., Tanga, P., Rivet, J. -P., Frappa, E., 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, J. -F., Metz, F., Erpelding, D., Nougayrède, P., 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., Aissa, D. Baba, Grigahcene, Z., Briggs, D., Broadbent, S., Denyer, P., Haigh, N. J., Quinn, N., Thurston, G., Fossey, S. J., Arena, C., Jennings, M., Talbot, J., Alonso, S., Reche, A. Román, Casanova, V., Briggs, E., Iglesias-Marzoa, R., Ibáñez, J. Abril, Martín, M. C. Díaz, González, H., García, J. L. Maestre, Marchant, J., Ordonez-Etxeberria, I., Martorell, P., Salamero, J., Organero, F., Ana, L., Fonseca, F., Peris, V., Brevia, O., Selva, A., Perello, C., Cabedo, V., Gonçalves, R., Ferreira, M., Dias, F. Marques, Daassou, A., Barkaoui, K., Benkhaldoun, Z., Guennoun, M., Chouqar, J., Jehin, E., Rinner, C., Lloyd, J., Moutamid, M. El, Lamarche, C., Pollock, J. T., Caton, D. B., Kouprianov, V., Timerson, B. W., Blanchard, G., Payet, B., Peyrot, A., Teng-Chuen-Yu, J. -P., Françoise, J., Mondon, B., Payet, T., Boissel, C., Castets, M., Hubbard, W. B., Hill, R., Reitsema, H. J., Mousis, O., Ball, L., Neilsen, G., Hutcheon, S., Lay, K., Anderson, P., Moy, M., Jonsen, M., Pink, I., Walters, R., and Downs, B.

Subjects
Astrophysics - Earth and Planetary Astrophysics
Abstract

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. 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. We used Abel inversions and direct ray-tracing code to provide the density, pressure, and temperature profiles in the altitude range $\sim$8 km to $\sim$190 km, corresponding to pressure levels from 9 {\mu}bar down to a few nanobars. Results. (i) A pressure of 1.18$\pm$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., Comment: 52 pages, 26 figures in the main paper, 2 figures in appendix B, 9 figures in appendix C, 1 long table over 5 pages

Published
2022
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3. The 2017 May 20$^{\rm th}$ stellar occultation by the elongated centaur (95626) 2002 GZ$_{32}$

Author

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., Leiva, A. Fuambuena, 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., and Alí-Lagoa, V.

Subjects
Astrophysics - Earth and Planetary Astrophysics, Astrophysics - Solar and Stellar Astrophysics
Abstract

We predicted a stellar occultation of the bright star Gaia DR1 4332852996360346368 (UCAC4 385-75921) (m$_{\rm V}$= 14.0 mag) by the centaur 2002 GZ$_{32}$ for 2017 May 20$^{\rm th}$. 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 multi-chord stellar occultation is reported. By means of an elliptical fit to the occultation chords we obtained the limb of 2002 GZ$_{32}$ during the occultation, resulting in an ellipse with axes of 305 $\pm$ 17 km $\times$ 146 $\pm$ 8 km. From this limb, thanks to a rotational light curve obtained shortly after the occultation, we derived the geometric albedo of 2002 GZ$_{32}$ ($p_{\rm V}$ = 0.043 $\pm$ 0.007) and a 3-D ellipsoidal shape with axes 366 km $\times$ 306 km $\times$ 120 km. This shape is not fully consistent with a homogeneous body in hydrostatic equilibrium for the known rotation period of 2002 GZ$_{32}$. 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 GZ$_{32}$ were detected from the occultation, but narrow and thin rings cannot be discarded., Comment: Accepted for publication in MNRAS (8-Dec.-2020), 15 pages, 9 figures

Published
2020
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4. The multichord stellar occultation by the centaur Bienor on January 11, 2019

Author

Fernández-Valenzuela, E., primary, Morales, N., additional, Vara-Lubiano, M., additional, Ortiz, J. L., additional, Benedetti-Rossi, G., additional, Sicardy, B., additional, Kretlow, M., additional, Santos-Sanz, P., additional, Morgado, B., additional, Souami, D., additional, Organero, F., additional, Ana, L., additional, Fonseca, F., additional, Román, A., additional, Alonso, S., additional, Gonçalves, R., additional, Ferreira, M., additional, Iglesias-Marzoa, R., additional, Lamadrid, J. L., additional, Alvarez-Candal, A., additional, Assafin, M., additional, Braga-Ribas, F., additional, Camargo, J. I. B., additional, Colas, F., additional, Desmars, J., additional, Duffard, R., additional, Lecacheux, J., additional, Gomes-Júnior, A. R., additional, Rommel, F. L., additional, Vieira-Martins, R., additional, Pereira, C. L., additional, Casanova, V., additional, Selva, A., additional, Perelló, C., additional, Mottola, S., additional, Hellmich, S., additional, Maestre, J. L., additional, Castro-Tirado, A. J., additional, Pal, A., additional, Trigo-Rodriguez, J. M., additional, Beisker, W., additional, Laporta, A., additional, Garcés, M., additional, Escaned, L., additional, and Bretton, M., additional

Published
2023
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5. VizieR Online Data Catalog: Triton light curves from 05/10/2017 (Marques Oliveira+, 2022)

Author

Marques Oliveira, J., Sicardy, B., Gomes-Junior, A. R., Ortiz, J. L., Strobel, D. F., Bertrand, T., Forget, F., Lellouch, E., Desmars, J., Berard, D., Doressoundiram, A., Lecacheux, J., Leiva, R., Meza, E., Roques, F., Souami, D., Widemann, T., Santos-Sanz, P., Morales, N., Duffard, R., Fernandez-Valenzuela, E., Castro-Tirado, A. J., Braga-Ribas, F., Morgado, B. E., Assafin, M., Camargo, J. I. B., Vieira-Martins, R., Benedetti-Rossi, G., Santos-Filho, S., Banda-Huarca, M. V., Quispe-Huaynasi, F., Pereira, C. L., Rommel, F. L., Margoti, G., Dias-Oliveira, A., Colas, F., Berthier, J., Renner, S., Hueso, R., Perez-Hoyos, S., Sanchez-Lavega, A., Rojas, J. F., Beisker, W., Kretlow, M., Herald, D., Gault, D., Bath, K.-L., Bode, H.-J., Bredner, E., Guhl, K., Haymes, T. V., Hummel, E., Kattentidt, B., Klos, O., Pratt, A., Thome, B., Avdellidou, C., Gazeas, K., Karampotsiou, E., Tzouganatos, L., Kardasis, E., Christou, A. A., Xilouris, E. M., Alikakos, I., Gourzelas, A., Liakos, A., Charmandaris, V., Jelinek, M., Strobl, J., Eberle, A., Rapp, K., Gahrken, B., Kowo Llik, S., Bitzer, R., Miller, M., Herzogenrath, G., Frangenberg, D., Brandis, L., Puetz, I., Perdelwitz, V., Piehler, G. M., Riepe, P., von Poschinger, K., Baruffetti, P., Cenadelli, D., Christille, J.-M., Ciabattari, F., Di, Luca R., Alboresi, D., Leto, G., Zanmar Sanchez, R., Bruno, P., Occhipinti, G., Morrone, L., Cupolino, L., Noschese, A., Vecchione, A., Scalia, C., Lo Savio, R., Giardina, G., Kamoun, S., Barbosa, R., Behrend, R., Spano, M., Bouchet, E., Cottier, M., Falco, L., Gallego, S., Tortorelli, L., Sposetti, S., Sussenbach, J., van den Abbeel, F., Andre, P., Llibre, M., Pailler, F., Ardissone, J., Boutet, M., Sanchez, J., Bretton, M., Cailleau, A., Pic, V., Granier, L., Chauvet, R., Conjat, M., Dauvergne, J. L., Dechambre, O., Delay, P., Delcroix, M., Rousselot, L., Ferreira, J., Machado, P., Tanga, P., Rivet, J.-P., Frappa, E., 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, J.-F., Metz, F., Erpelding, D., Nougayrede, P., 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, S., Denyer, P., Haigh, N. J., Quinn, N., Thurston, G., Fossey, S. J., Arena, C., Jennings, M., Talbot, J., Alonso, S., Roman Reche, A., Casanova, V., Briggs, E., Iglesias-Marzoa, R., Abril Ibanez, J., Diaz, Martin M. C., Gonzalez, H., Maestre Garcia, J. L., Marchant, J., Ordonez-Etxeberria, I., Martorell, P., Salamero, J., Organero, F., Ana, L., Fonseca, F., Peris, V., Brevia, O., Selva, A., Perello, C., Cabedo, V., Goncalves, R., Ferreira, M., Marques Dias, F., Daassou, A., Barkaoui, K., Benkhaldoun, Z., Guennoun, M., Chouqar, J., Jehin, E., Rinner, C., Lloyd, J., El Moutamid, M., Lamarche, C., Pollock, J. T., Caton, D. B., Kouprianov, V., Timerson, B. W., Blanchard, G., Payet, B., Peyrot, A., Teng-Chuen-Yu, J.-P., Francoise, J., Mondon, B., Payet, T., Boissel, C., Castets, M., Hubbard, W. B., Hill, R., Reitsema, H. J., Mousis, O., Ball, L., Hutcheon, S., Lay, K., Anderson, P., Moy, M., Jonsen, M., Pink, I., Walters, R., Downs, B., Institut de Mécanique Céleste et de Calcul des Ephémérides (IMCCE), 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)-Université de Lille-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)

Subjects
Photometry, Planets, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], Solar system
Abstract

International audience; The data provided features all light curves from the 5 October 2017 event. The names of the files are the same names, in lower caps and with no spaces, that are presented in Figures C.1 and C.2. The first column of all files is the time in seconds, starting on 5 October 2017 00:00:00 UTC. The second column of all files is the normalised flux, where the unocculted flux oscillates around 1. (2 data files).

Published
2022

6. 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

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

Author

Marques Oliveira, J., primary, Sicardy, B., additional, Gomes-Júnior, A. R., additional, Ortiz, J. L., additional, Strobel, D. F., additional, Bertrand, T., additional, Forget, F., additional, Lellouch, E., additional, Desmars, J., additional, Bérard, D., additional, Doressoundiram, A., additional, Lecacheux, J., additional, Leiva, R., additional, Meza, E., additional, Roques, F., additional, Souami, D., additional, Widemann, T., additional, Santos-Sanz, P., additional, Morales, N., additional, Duffard, R., additional, Fernández-Valenzuela, E., additional, Castro-Tirado, A. J., additional, Braga-Ribas, F., additional, Morgado, B. E., additional, Assafin, M., additional, Camargo, J. I. B., additional, Vieira-Martins, R., additional, Benedetti-Rossi, G., additional, Santos-Filho, S., additional, Banda-Huarca, M. V., additional, Quispe-Huaynasi, F., additional, Pereira, C. L., additional, Rommel, F. L., additional, Margoti, G., additional, Dias-Oliveira, A., additional, Colas, F., additional, Berthier, J., additional, Renner, S., additional, Hueso, R., additional, Pérez-Hoyos, S., additional, Sánchez-Lavega, A., additional, Rojas, J. F., additional, Beisker, W., additional, Kretlow, M., additional, Herald, D., additional, Gault, D., additional, Bath, K.-L., additional, Bode, H.-J., additional, Bredner, E., additional, Guhl, K., additional, Haymes, T. V., additional, Hummel, E., additional, Kattentidt, B., additional, Klös, O., additional, Pratt, A., additional, Thome, B., additional, Avdellidou, C., additional, Gazeas, K., additional, Karampotsiou, E., additional, Tzouganatos, L., additional, Kardasis, E., additional, Christou, A. A., additional, Xilouris, E. M., additional, Alikakos, I., additional, Gourzelas, A., additional, Liakos, A., additional, Charmandaris, V., additional, Jelínek, M., additional, Štrobl, J., additional, Eberle, A., additional, Rapp, K., additional, Gährken, B., additional, Klemt, B., additional, Kowollik, S., additional, Bitzer, R., additional, Miller, M., additional, Herzogenrath, G., additional, Frangenberg, D., additional, Brandis, L., additional, Pütz, I., additional, Perdelwitz, V., additional, Piehler, G. M., additional, Riepe, P., additional, von Poschinger, K., additional, Baruffetti, P., additional, Cenadelli, D., additional, Christille, J.-M., additional, Ciabattari, F., additional, Di Luca, R., additional, Alboresi, D., additional, Leto, G., additional, Zanmar Sanchez, R., additional, Bruno, P., additional, Occhipinti, G., additional, Morrone, L., additional, Cupolino, L., additional, Noschese, A., additional, Vecchione, A., additional, Scalia, C., additional, Lo Savio, R., additional, Giardina, G., additional, Kamoun, S., additional, Barbosa, R., additional, Behrend, R., additional, Spano, M., additional, Bouchet, E., additional, Cottier, M., additional, Falco, L., additional, Gallego, S., additional, Tortorelli, L., additional, Sposetti, S., additional, Sussenbach, J., additional, Van Den Abbeel, F., additional, André, P., additional, Llibre, M., additional, Pailler, F., additional, Ardissone, J., additional, Boutet, M., additional, Sanchez, J., additional, Bretton, M., additional, Cailleau, A., additional, Pic, V., additional, Granier, L., additional, Chauvet, R., additional, Conjat, M., additional, Dauvergne, J. L., additional, Dechambre, O., additional, Delay, P., additional, Delcroix, M., additional, Rousselot, L., additional, Ferreira, J., additional, Machado, P., additional, Tanga, P., additional, Rivet, J.-P., additional, Frappa, E., additional, Irzyk, M., additional, Jabet, F., additional, Kaschinski, M., additional, Klotz, A., additional, Rieugnie, Y., additional, Klotz, A. N., additional, Labrevoir, O., additional, Lavandier, D., additional, Walliang, D., additional, Leroy, A., additional, Bouley, S., additional, Lisciandra, S., additional, Coliac, J.-F., additional, Metz, F., additional, Erpelding, D., additional, Nougayrède, P., additional, Midavaine, T., additional, Miniou, M., additional, Moindrot, S., additional, Morel, P., additional, Reginato, B., additional, Reginato, E., additional, Rudelle, J., additional, Tregon, B., additional, Tanguy, R., additional, David, J., additional, Thuillot, W., additional, Hestroffer, D., additional, Vaudescal, G., additional, Baba Aissa, D., additional, Grigahcene, Z., additional, Briggs, D., additional, Broadbent, S., additional, Denyer, P., additional, Haigh, N. J., additional, Quinn, N., additional, Thurston, G., additional, Fossey, S. J., additional, Arena, C., additional, Jennings, M., additional, Talbot, J., additional, Alonso, S., additional, Román Reche, A., additional, Casanova, V., additional, Briggs, E., additional, Iglesias-Marzoa, R., additional, Abril Ibáñez, J., additional, Díaz Martín, M. C., additional, González, H., additional, Maestre García, J. L., additional, Marchant, J., additional, Ordonez-Etxeberria, I., additional, Martorell, P., additional, Salamero, J., additional, Organero, F., additional, Ana, L., additional, Fonseca, F., additional, Peris, V., additional, Brevia, O., additional, Selva, A., additional, Perello, C., additional, Cabedo, V., additional, Gonçalves, R., additional, Ferreira, M., additional, Marques Dias, F., additional, Daassou, A., additional, Barkaoui, K., additional, Benkhaldoun, Z., additional, Guennoun, M., additional, Chouqar, J., additional, Jehin, E., additional, Rinner, C., additional, Lloyd, J., additional, El Moutamid, M., additional, Lamarche, C., additional, Pollock, J. T., additional, Caton, D. B., additional, Kouprianov, V., additional, Timerson, B. W., additional, Blanchard, G., additional, Payet, B., additional, Peyrot, A., additional, Teng-Chuen-Yu, J.-P., additional, Françoise, J., additional, Mondon, B., additional, Payet, T., additional, Boissel, C., additional, Castets, M., additional, Hubbard, W. B., additional, Hill, R., additional, Reitsema, H. J., additional, Mousis, O., additional, Ball, L., additional, Neilsen, G., additional, Hutcheon, S., additional, Lay, K., additional, Anderson, P., additional, Moy, M., additional, Jonsen, M., additional, Pink, I., additional, Walters, R., additional, and Downs, B., additional

Published
2022
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8. Constraints on the structure and seasonal variations of Triton's atmosphere from the 5 October 2017 stellar occultation and previous observations

Author

Marques Oliveira, J. Sicardy, B. Gomes-Júnior, 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, P. Morales, N. Duffard, R. Fernández-Valenzuela, E. Castro-Tirado, A.J. Braga-Ribas, F. Morgado, B.E. Assafin, M. Camargo, J.I.B. Vieira-Martins, R. Benedetti-Rossi, G. Santos-Filho, S. Banda-Huarca, M.V. Quispe-Huaynasi, F. Pereira, C.L. Rommel, F.L. Margoti, G. Dias-Oliveira, A. Colas, F. Berthier, J. Renner, S. Hueso, R. Pérez-Hoyos, S. Sánchez-Lavega, A. Rojas, J.F. Beisker, W. Kretlow, M. 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, C. Gazeas, K. Karampotsiou, E. Tzouganatos, L. Kardasis, E. Christou, A.A. Xilouris, E.M. Alikakos, I. Gourzelas, A. Liakos, A. Charmandaris, V. Jelínek, M. Štrobl, J. Eberle, A. Rapp, K. Gährken, B. Klemt, B. Kowollik, S. Bitzer, R. Miller, M. Herzogenrath, G. Frangenberg, D. Brandis, L. Pütz, I. Perdelwitz, V. Piehler, G.M. Riepe, P. Von Poschinger, K. Baruffetti, P. Cenadelli, D. Christille, J.-M. Ciabattari, F. Di Luca, R. Alboresi, D. Leto, G. Zanmar Sanchez, R. Bruno, P. Occhipinti, G. Morrone, L. Cupolino, L. Noschese, A. Vecchione, A. Scalia, C. Lo Savio, R. Giardina, G. Kamoun, S. Barbosa, R. Behrend, R. Spano, M. Bouchet, E. Cottier, M. Falco, L. Gallego, S. Tortorelli, L. Sposetti, S. Sussenbach, J. Van Den Abbeel, F. André, P. Llibre, M. Pailler, F. Ardissone, J. Boutet, M. Sanchez, J. Bretton, M. Cailleau, A. Pic, V. Granier, L. Chauvet, R. Conjat, M. Dauvergne, J.L. Dechambre, O. Delay, P. Delcroix, M. Rousselot, L. Ferreira, J. MacHado, P. Tanga, P. Rivet, J.-P. Frappa, E. 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, J.-F. Metz, F. Erpelding, D. Nougayrède, P. 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, S. Denyer, P. Haigh, N.J. Quinn, N. Thurston, G. Fossey, S.J. Arena, C. Jennings, M. Talbot, J. Alonso, S. Román Reche, A. Casanova, V. Briggs, E. Iglesias-Marzoa, R. Abril Ibáñez, J. Díaz Martín, M.C. González, H. Maestre García, J.L. Marchant, J. Ordonez-Etxeberria, I. Martorell, P. Salamero, J. Organero, F. Ana, L. Fonseca, F. Peris, V. Brevia, O. Selva, A. Perello, C. Cabedo, V. Gonçalves, R. Ferreira, M. Marques Dias, F. Daassou, A. Barkaoui, K. Benkhaldoun, Z. Guennoun, M. Chouqar, J. Jehin, E. Rinner, C. Lloyd, J. El Moutamid, M. Lamarche, C. Pollock, J.T. Caton, D.B. Kouprianov, V. Timerson, B.W. Blanchard, G. Payet, B. Peyrot, A. Teng-Chuen-Yu, J.-P. Françoise, J. Mondon, B. Payet, T. Boissel, C. Castets, M. Hubbard, W.B. Hill, R. Reitsema, H.J. Mousis, O. Ball, L. Neilsen, G. Hutcheon, S. Lay, K. Anderson, P. Moy, M. Jonsen, M. Pink, I. Walters, R. 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 ∼8 km to ∼190 km, corresponding to pressure levels from 9 μbar down to a few nanobars. Results. (i) A pressure of 1.18 ± 0.03 μbar 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 μbar. 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

9. The 2017 May 20 stellar occultation by the elongated centaur (95626) 2002 GZ32

Author

Santos-Sanz, P, primary, Ortiz, J L, additional, Sicardy, B, additional, Benedetti-Rossi, G, additional, Morales, N, additional, Fernández-Valenzuela, E, additional, Duffard, R, additional, Iglesias-Marzoa, R, additional, Lamadrid, J L, additional, Maícas, N, additional, Pérez, L, additional, Gazeas, K, additional, Guirado, J C, additional, Peris, V, additional, Ballesteros, F J, additional, Organero, F, additional, Ana-Hernández, L, additional, Fonseca, F, additional, Alvarez-Candal, A, additional, Jiménez-Teja, Y, additional, Vara-Lubiano, M, additional, Braga-Ribas, F, additional, Camargo, J I B, additional, Desmars, J, additional, Assafin, M, additional, Vieira-Martins, R, additional, Alikakos, J, additional, Boutet, M, additional, Bretton, M, additional, Carbognani, A, additional, Charmandaris, V, additional, Ciabattari, F, additional, Delincak, P, additional, Fuambuena Leiva, A, additional, González, H, additional, Haymes, T, additional, Hellmich, S, additional, Horbowicz, J, additional, Jennings, M, additional, Kattentidt, B, additional, Kiss, Cs, additional, Komžík, R, additional, Lecacheux, J, additional, Marciniak, A, additional, Moindrot, S, additional, Mottola, S, additional, Pal, A, additional, Paschalis, N, additional, Pastor, S, additional, Perello, C, additional, Pribulla, T, additional, Ratinaud, C, additional, Reyes, J A, additional, Sanchez, J, additional, Schnabel, C, additional, Selva, A, additional, Signoret, F, additional, Sonbas, E, additional, and Alí-Lagoa, V, additional

Published
2020
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10. Albedo and atmospheric constraints of dwarf planet Makemake from a stellar occultation

Author

Ortiz, J. L., Sicardy, B., Braga-Ribas, F., Alvarez-Candal, A., Lellouch, E., Duffard, R., Pinilla-Alonso, N., Ivanov, V. D., Littlefair, S. P., Camargo, J. I. B., Assafin, M., Unda-Sanzana, E., Jehin, E., Morales, N., Tancredi, G., Gil-Hutton, R., de la Cueva, I., Colque, J. P., Da Silva Neto, D. N., Manfroid, J., Thirouin, A., Gutiérrez, P. J., Lecacheux, J., Gillon, M., Maury, A., Colas, F., Licandro, J., Mueller, T., Jacques, C., Weaver, D., Milone, A., Salvo, R., Bruzzone, S., Organero, F., Behrend, R., Roland, S., Vieira-Martins, R., Widemann, T., Roques, F., Santos-Sanz, P., Hestroffer, D., Dhillon, V. S., Marsh, T. R., Harlingten, C., Bagatin, Campo A., Alonso, M. L., Ortiz, M., Colazo, C., Lima, H. J. F., Oliveira, A. S., Kerber, L. O., Smiljanic, R., Pimentel, E., Giacchini, B., Cacella, P., and Emilio, M.

Published
2012
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11. A Pluto-like radius and a high albedo for the dwarf planet Eris from an occultation

Author

Sicardy, B., Ortiz, J. L., Assafin, M., Jehin, E., Maury, A., Lellouch, E., Hutton, Gil R., Braga-Ribas, F., Colas, F., Hestroffer, D., Lecacheux, J., Roques, F., Santos-Sanz, P., Widemann, T., Morales, N., Duffard, R., Thirouin, A., Castro-Tirado, A. J., Jelínek, M., Kubánek, P., Sota, A., Sánchez-Ramírez, R., Andrei, A. H., Camargo, J. I. B., da Silva Neto, D. N., Gomes, Ramos A., Martins, Vieira R., Gillon, M., Manfroid, J., Tozzi, G. P., Harlingten, C., Saravia, S., Behrend, R., Mottola, S., Melendo, García E., Peris, V., Fabregat, J., Madiedo, J. M., Cuesta, L., Eibe, M. T., Ullán, A., Organero, F., Pastor, S., de los Reyes, J. A., Pedraz, S., Castro, A., de la Cueva, I., Muler, G., Steele, I. A., Cebrián, M., Montañés-Rodríguez, P., Oscoz, A., Weaver, D., Jacques, C., Corradi, W. J. B., Santos, F. P., Reis, W., Milone, A., Emilio, M., Gutiérrez, L., Vázquez, R., and Hernández-Toledo, H.

Published
2011
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12. A superbolide recorded over Spain on July 13, 2012

Author

Madiedo Gil, José María|||0000-0003-0806-5194, Trigo Rodríguez, Josep María, Zamorano, J., Sánchez de Miguel, A., Ocaña Gónzalez, Francisco, Izquierdo Gómez, Jaime, Ortiz Moreno, José Luis, Castro Tirado, Alberto J., Morales, Nicolás, Galadí, D., Guindos, E. de, Lacruz, J., Organero, F., Hernández, L. A., Fonseca, F., Tapia, Mar, and Cabrera Caño, Jesús

Abstract

One of the aims of the SPanish Meteor Network (SPMN) is the recovery and analysis of meteorites. So, we focus special attention on very bright fireballs, as under appropriate conditions these unusual events may give rise to meteorite falls. For this purpose we operate 25 meteor observing stations that monitor the night sky over Spain and neighbouring areas. These provide useful data for the determination of radiant, orbital, photometric and chemical parameters [1, 2, 3]. In this context, we present here the first results of the analysis of a superbolide observed over the Iberian Peninsula on July 13, 2012.

Published
2013

13. The stellar occultation by Makemake on 2011 April 23

Author

Ortiz, J. L., Sicardy, B., Assafin, M., Alvarez-Candal, A., Valentin Ivanov, Camargo, J., Littlefair, S., Unda-Sanzana, E., Jehin, E., Braga-Ribas, F., Lellouch, E., Morales, N., Licandro, J., Gil-Hutton, R., Duffard, R., Colque, J. P., Tancredi, G., Mafroid, J., Thirouin, A., Lecacheux, J., Gillon, M., Maury, A., Colas, F., Jaques, C., Weaver, D., Milone, A., Salvo, S., Bruzzone, S., Organero, F., Behrend, R., Roland, S., Vieira-Martins, R., Widemann, T., Roques, F., Santos-Sanz, P., Hestroffer, D., Instituto de Astrofisica de Andalucia-CSIC, Solar System Department, Granada, Spain, Observatório do Valongo, Universidade Federal do Rio de Janeiro, European Southern Observatory, Chile, Observatorio Nacional / MCT, Brazil, Duke University [Durham], Instituto de Astronomia, Universidad Catolica del Norte, University of Liège, Institut de Mécanique Céleste et de Calcul des Ephémérides (IMCCE), Université Pierre et Marie Curie - Paris 6 (UPMC)-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)-Université de Lille-Centre National de la Recherche Scientifique (CNRS)

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

International audience; We have taken advantage of a stellar occultation by the dwarf planet Makemake on 2011 April 23, to determine several of its main physical properties. We present results from a multisite campaign with 8 positive occultation detections from 5 different sites, including data from the 8-m VLT and 3.5-m NTT telescopes in Chile, which have very high temporal resolution. Because the star was significantly fainter than Makemake (setting a record in the magnitude of a star whose occultation has been detected), the occultation resulted in a drop of just ~0.3 mag in the lightcurves. From the lightcurves we have been able to determine the size and shape of the body, its geometric albedo and constraints on its atmosphere.

14. The 2017 May 20 stellar occultation by the elongated centaur (95626) 2002 GZ32

Author

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. Komzík, 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.

Abstract

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. © 2021 2020 The Author(s) Published by Oxford University Press on behalf of Royal Astronomical Society.

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