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1. A study of centaur (54598) Bienor from multiple stellar occultations and rotational light curves

Author: Rizos, J. L., Fernández-Valenzuela, E., Ortiz, J. L., Rommel, F. L., Sicardy, B., Morales, N., Santos-Sanz, P., Leiva, R., Vara-Lubiano, M., Morales, R., Kretlow, M., Alvarez-Candal, A., Holler, B. J., Duffard, R., Gómez-Limón, J. M., Desmars, J., Souami, D., Assafin, M., Benedetti-Rossi, G., Braga-Ribas, F., Camargo, J. I. B., Colas, F., Lecacheux, J., Gomes-Júnior, A. R., Vieira-Martins, R., Pereira, C. L., Morgado, B., Kilic, Y., Redfield, S., Soloff, C., McGregor, K., Green, K., Midavaine, T., Schreurs, O., Lecossois, M., Boninsegna, R., Ida, M., Cam, P. Le, Isobe, K., Watanabe, Hayato, Yuasa, S., Watanabe, Hikaru, and Kidd, S.
Subjects: Astrophysics - Earth and Planetary Astrophysics
Abstract: Centaurs, distinguished by their volatile-rich compositions, play a pivotal role in understanding the formation and evolution of the early solar system, as they represent remnants of the primordial material that populated the outer regions. Stellar occultations offer a means to investigate their physical properties, including shape, rotational state, or the potential presence of satellites and rings. This work aims to conduct a detailed study of the centaur (54598) Bienor through stellar occultations and rotational light curves from photometric data collected during recent years. We successfully predicted three stellar occultations by Bienor, which were observed from Japan, Eastern Europe, and the USA. In addition, we organized observational campaigns from Spain to obtain rotational light curves. At the same time, we develop software to generate synthetic light curves from three-dimensional shape models, enabling us to validate the outcomes through computer simulations. We resolve Bienor's projected ellipse for December 26, 2022, determine a prograde sense of rotation, and confirm an asymmetric rotational light curve. We also retrieve the axes of its triaxial ellipsoid shape as a = (127 $\pm$ 5) km, b = (55 $\pm$ 4) km, and c = (45 $\pm$ 4) km. Moreover, we refine the rotation period to 9.1736 $\pm$ 0.0002 hours and determine a geometric albedo of (6.5 $\pm$ 0.5) %, higher than previously determined by other methods. Finally, by comparing our findings with previous results and simulated rotational light curves, we analyze whether an irregular or contact-binary shape, the presence of an additional element such as a satellite, or significant albedo variations on Bienor's surface, may be present.
Published: 2024
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2. The stellar occultation by (319) Leona on 13 September 2023 in preparation for the occultation of Betelgeuse

Author: Ortiz, J. L., Kretlow, M., Schnabel, C., Morales, N., Flores-Martín, J., González, M. Sánchez, Casarramona, F., Selva, A., Perelló, C., Román-Reche, A., Alonso, S., Rizos, J. L., Gonçalves, R., Castillo, A., Madiedo, J. M., Sánchez, P. Martínez, andújar, J. M. Fernández, Maestre, J. L., Smith, E., Gil, M., Pelenjow, V., Soriano, S. Moral, Martí, J., Luque-Escamilla, P. L., Casas, R., Casal, J. Delgado, Rovira, J., Aceituno, F. J., Dekert, V., Guimerá, V. de Ory, Estepa, J. Serrano, Kilic, Y., Leiva, R., Santos-Sanz, P., Duffard, R., Fernández-Valenzuela, E., Vara-Lubiano, M., Alvarez-Candal, A., and Rommel, F. L.
Subjects: Astrophysics - Earth and Planetary Astrophysics, Astrophysics - Instrumentation and Methods for Astrophysics, Astrophysics - Solar and Stellar Astrophysics
Abstract: On 12 December 2023, the star $\alpha$ Orionis (Betelgeuse) will be occulted by the asteroid (319) Leona. This represents an extraordinary and unique opportunity to analyze the diameter and brightness distribution of Betelgeuse's photosphere with extreme angular resolution by studying the light curve as the asteroid occults the star from different points on Earth and at different wavelengths. Here we present observations of another occultation by Leona on 13 September 2023 to determine its projected shape and size in preparation for the December 12th event. The occultation observation campaign was highly successful. The effective diameter in projected area derived from the positive detections at 17 sites turned out to be 66 km $\pm$ 2 km using an elliptical fit to the instantaneous limb. The body is highly elongated, with dimensions of 79.6 $\pm$ 2.2 km x 54.8 $\pm$ 1.3 km in its long and short axis, respectively, at the occultation time. Also, an accurate position coming from the occultation, to improve the orbit determination of Leona for December 12 is provided., Comment: Two figures. Letter submitted to A&A
Published: 2023
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3. Constraints on (2060) Chiron's size, shape, and surrounding material from the November 2018 and September 2019 stellar occultations

Author: Braga-Ribas, Felipe, Pereira, C. L., Sicardy, B., Ortiz, J. L., Desmars, J., Sickafoose, A., Emilio, M., Morgado, B., Margoti, G., Rommel, F. L., Camargo, J. I. B., Assafin, M., Vieira-Martins, R., Gomes-Júnior, A. R., Santos-Sanz, P., Morales, N., Kretlow, M., Lecacheux, J., Colas, F., Boninsegna, R., Schreurs, O., Dauvergne, J. L., Fernandez, E., van Heerden, H. J., González, H., Bihel, D., and Jankowsky, F.
Subjects: Astrophysics - Earth and Planetary Astrophysics
Abstract: After the discovery of rings around the largest known Centaur object, (10199) Chariklo, we carried out observation campaigns of stellar occultations produced by the second-largest known Centaur object, (2060) Chiron, to better characterize its physical properties and presence of material on its surroundings. We predicted and successfully observed two stellar occultations by Chiron. These observations were used to constrain its size and shape by fitting elliptical limbs with equivalent surface radii in agreement with radiometric measurements. Constraints on the (2060) Chiron shape are reported for the first time. Assuming an equivalent radius of R$_{equiv}$ = 105$^{+6}_{-7}$ km, we obtained a semi-major axis of a = 126 $\pm$ 22 km. Considering Chiron's true rotational light curve amplitude and assuming it has a Jacobi equilibrium shape, we were able to derive a 3D shape with a semi-axis of a = 126 $\pm$ 22 km, b = 109 $\pm$ 19 km, and c = 68 $\pm$ 13 km, implying in a volume-equivalent radius of R$_{vol}$ = 98 $\pm$ 17 km, implying a density of 1119 $\pm$ 4 kg m$^{-3}$. We determined the physical properties of the 2011 secondary events around Chiron, which may then be directly compared with those of Chariklo rings, as the same method was used. Data obtained from SAAO in 2018 do not show unambiguous evidence of the proposed rings, mainly due to the large sampling time. Meanwhile, we discarded the possible presence of a permanent ring similar to (10199) Chariklo's C1R in optical depth and extension. Using the first multi-chord stellar occultation by (2060) Chiron and considering it to have a Jacobi equilibrium shape, we derived its 3D shape. New observations of a stellar occultation by (2060) Chiron are needed to further investigate the material's properties around Chiron, such as the occultation predicted for September 10, 2023.
Published: 2023
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4. The changing material around (2060) Chiron from an occultation on 2022 December 15

Author: Ortiz, J. L., Pereira, C. L., Sicardy, B., Braga-Ribas, F., Takey, A., Fouad, A. M., Shaker, A. A., Kaspi, S., Brosch, N., Kretlow, M., Leiva, R., Desmars, J., Morgado, B. E., Morales, N., Vara-Lubiano, M., Santos-Sanz, P., Fernández-Valenzuela, E., Souami, D., Duffard, R., Rommel, F. L., Kilic, Y., Erece, O., Koseoglu, D., Ege, E., Morales, R., Alvarez-Candal, A., Rizos, J. L., Gómez-Limón, J. M., Assafin, M., Vieira-Martins, R., Gomes-Júnior, A. R., Camargo, J. I. B., and Lecacheux, J.
Subjects: Astrophysics - Earth and Planetary Astrophysics
Abstract: We could accurately predict the shadow path and successfully observe an occultation of a bright star by Chiron on 2022 December 15. The Kottamia Astronomical Observatory in Egypt did not detect the occultation by the solid body, but we detected three extinction features in the light curve that had symmetrical counterparts with respect to the central time of the occultation. One of the features is broad and shallow, whereas the other two features are sharper with a maximum extinction of $\sim$25$\%$ at the achieved spatial resolution of 19 km per data point. From the Wise observatory in Israel, we detected the occultation caused by the main body and several extinction features surrounding the body. When all the secondary features are plotted in the sky plane we find that they can be caused by a broad $\sim$580 km disk with concentrations at radii of 325 \pm 16 km and 423 \pm 11 km surrounding Chiron. At least one of these structures appears to be outside the Roche limit. The ecliptic coordinates of the pole of the disk are $\lambda$ = 151$^\circ~\pm$ 8$^\circ$ and $\beta$ = 18$^\circ~\pm$ 11$^\circ$, in agreement with previous results. We also show our long-term photometry indicating that Chiron had suffered a brightness outburst of at least 0.6 mag between March and September 2021 and that Chiron was still somewhat brighter at the occultation date than at its nominal pre-outburst phase. The outermost extinction features might be consistent with a bound or temporarily bound structure associated with the brightness increase. However, the nature of the brightness outburst is unclear, and it is also unclear whether the dust or ice released in the outburst could be feeding a putative ring structure or if it emanated from it., Comment: 6 pages, 4, figures
Published: 2023
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5. The two rings of (50000) Quaoar

Author: Pereira, C. L., Sicardy, B., Morgado, B. E., Braga-Ribas, F., Fernández-Valenzuela, E., Souami, D., Holler, B. J., Boufleur, R. C., Margoti, G., Assafin, M., Ortiz, J. L., Santos-Sanz, P., Epinat, B., Kervella, P., Desmars, J., Vieira-Martins, R., Kilic, Y., Gomes-Júnior, A. R., Camargo, J. I. B., Emilio, M., Vara-Lubiano, M., Kretlow, M., Albert, L., Alcock, C., Ball, J. G., Bender, K., Buie, M. W., Butterfield, K., Camarca, M., Castro-Chacón, J. H., Dunford, R., Fisher, R. S., Gamble, D., Geary, J. C., Gnilka, C. L., Green, K. D., Hartman, Z. D., Huang, C-K., Januszewski, H., Johnston, J., Kagitani, M., Kamin, R., Kavelaars, J. J., Keller, J. M., de Kleer, K. R., Lehner, M. J., Luken, A., Marchis, F., Marlin, T., McGregor, K., Nikitin, V., Nolthenius, R., Patrick, C., Redfield, S., Rengstorf, A. W., Reyes-Ruiz, M., Seccull, T., Skrutskie, M. F., Smith, A. B., Sproul, M., Stephens, A. W., Szentgyorgyi, A., Sánchez-Sanjuán, S., Tatsumi, E., Verbiscer, A., Wang, S-Y., Yoshida, F., Young, R., and Zhang, Z-W.
Subjects: Astrophysics - Earth and Planetary Astrophysics
Abstract: Quaoar is a classical Trans-Neptunian Object (TNO) with an area equivalent diameter of 1,100 km and an orbital semi-major axis of 43.3 astronomical units. Based on stellar occultations observed between 2018 and 2021, an inhomogeneous ring (Q1R, Quaoar's first ring) was detected around this body. Aims. A new stellar occultation by Quaoar was observed on August 9th, 2022 aiming to improve Quaoar's shape models and the physical parameters of Q1R while searching for additional material around the body. Methods. The occultation provided nine effective chords across Quaoar, pinning down its size, shape, and astrometric position. Large facilities, such as Gemini North and the Canada-France-Hawaii Telescope (CFHT), were used to obtain high acquisition rates and signal-to-noise ratios. The light curves were also used to characterize the Q1R ring (radial profiles and orbital elements). Results. Quaoar's elliptical fit to the occultation chords yields the limb with an apparent semi-major axis of $579.5\pm4.0$ km, apparent oblateness of $0.12\pm0.01$, and area-equivalent radius of $543\pm2$ km. Quaoar's limb orientation is consistent with Q1R and Weywot orbiting in Quaoar's equatorial plane. The orbital radius of Q1R is refined to a value of $4,057\pm6$ km. The radial opacity profile of the more opaque ring profile follows a Lorentzian shape that extends over 60 km, with a full width at half maximum (FWHM) of $\sim5$ km and a peak normal optical depth of 0.4. Besides the secondary events related to the already reported rings, new secondary events detected during the August 2022 occultation in three different data sets are consistent with another ring around Quaoar with a radius of $2,520\pm20$ km, assuming the ring is circular and co-planar with Q1R. This new ring has a typical width of 10 km and a normal optical depth of $\sim$0.004. Like Q1R, it also lies outside Quaoar's classical Roche limit., Comment: Accepted for publication in Astronomy & Astrophysics (17-April-2023). 18 pages, 12 figures
Published: 2023
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6. 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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7. An astrometric mass estimate for asteroid (223) Rosa

Author: Kretlow, M.
Subjects: Astrophysics - Earth and Planetary Astrophysics
Abstract: Outer main belt asteroid (223) Rosa is a possible flyby target of opportunity for ESA's (European Space Agency) JUpiter ICy moons Explorer (JUICE) mission when passing the asteroid belt on the way to Jupiter. The very low albedo and the featureless red spectra indicate a P-type asteroid in the Tholen taxonomy, though the yet known bulk density did not match very well this classification. Aim of this work was to derive new estimates for the mass and for the bulk density for (223) Rosa. The mass of Rosa was derived by analyzing the gravitational deflection of small `test' asteroids which had a close encounter with Rosa in the past. To find such events suitable for the mass determination, an encounter search with about 900,000 asteroids over the time span $1980-2030$ was performed. Three encounters were identified from which two independent mass estimates for Rosa were derived: $M = (5.32 \pm 2.17) \times 10^{17}$ kg and $M = (3.15 \pm 1.14) \times 10^{17}$ kg, respectively. The weighted mean is $M = (3.62 \pm 1.25) \times 10^{17}$ kg. This yields to a bulk density of $\rho = 1.2 \pm 0.5 \mathrm{\,g\,cm^{-3}}$, when adopting an effective diameter of $D = 83 \pm 8$ km. This bulk density estimate is consistent with typical densities for Tholen taxonomy P-type asteroids., Comment: 6 pages, 4 figures, accepted for publication in A&A
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: 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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9. Refined physical parameters for Chariklo's body and rings from stellar occultations observed between 2013 and 2020

Author: Morgado, B. E., Sicardy, B., Braga-Ribas, F., Desmars, J., Gomes-Júnior, A. R., Bérard, D., Leiva, R., Ortiz, J. L., Vieira-Martins, R., Benedetti-Rossi, G., Santos-Sanz, P., Camargo, J. I. B., Duffard, R., Rommel, F. L., Assafin, M., Boufleur, R. C., Colas, F., Kretlow, M., Beisker, W., Sfair, R., Snodgrass, C., Morales, N., Fernández-Valenzuela, E., Amaral, L. S., Amarante, A., Artola, R. A., Backes, M., Bath, K-L., Bouley, S., Buie, M. W., Cacella, P., Colazo, C. A., Colque, J. P., Dauvergne, J-L., Dominik, M., Emilio, M., Erickson, C., Evans, R., Fabrega-Polleri, J., Garcia-Lambas, D., Giacchini, B. L., Hanna, W., Herald, D., Hesler, G., Hinse, T. C., Jacques, C., Jehin, E., Jørgensen, U. G., Kerr, S., Kouprianov, V., Levine, S. E., Linder, T., Maley, P. D., Machado, D. I., Maquet, L., Maury, A., Melia, R., Meza, E., Mondon, B., Moura, T., Newman, J., Payet, T., Pereira, C. L., Pollock, J., Poltronieri, R. C., Quispe-Huaynasi, F., Reichart, D., de Santana, T., Schneiter, E. M., Sieyra, M. V., Skottfelt, J., Soulier, J. F., Starck, M., Thierry, P., Torres, P. J., Trabuco, L. L., Unda-Sanzana, E., Yamashita, T. A. R., Winter, O. C., Zapata, A., and Zuluaga, C. A.
Subjects: Astrophysics - Earth and Planetary Astrophysics
Abstract: The Centaur (10199) Chariklo has the first rings system discovered around a small object. It was first observed using stellar occultation in 2013. Stellar occultations allow the determination of sizes and shapes with kilometre accuracy and obtain characteristics of the occulting object and its vicinity. Using stellar occultations observed between 2017 and 2020, we aim at constraining Chariklo's and its rings physical parameters. We also determine the rings' structure, and obtain precise astrometrical positions of Chariklo. We predicted and organised several observational campaigns of stellar occultations by Chariklo. Occultation light curves were measured from the data sets, from which ingress and egress times, and rings' width and opacity were obtained. These measurements, combined with results from previous works, allow us to obtain significant constraints on Chariklo's shape and rings' structure. We characterise Chariklo's ring system (C1R and C2R), and obtain radii and pole orientations that are consistent with, but more accurate than, results from previous occultations. We confirmed the detection of W-shaped structures within C1R and an evident variation of radial width. The observed width ranges between 4.8 and 9.1 km with a mean value of 6.5 km. One dual observation (visible and red) does not reveal any differences in the C1R opacity profiles, indicating ring particle's size larger than a few microns. The C1R ring eccentricity is found to be smaller than 0.022 (3-sigma), and its width variations may indicate an eccentricity higher than 0.005. We fit a tri-axial shape to Chariklo's detections over eleven occultations and determine that Chariklo is consistent with an ellipsoid with semi-axes of 143.8, 135.2 and 99.1 km. Ultimately, we provided seven astrometric positions at a milliarcseconds accuracy level, based on Gaia EDR3, and use it to improve Chariklo's ephemeris., Comment: 32 pages, 11 Figures in the main text, paper was accepted for publication in Section 10. Planets and planetary systems of Astronomy and Astrophysics on 12/07/2021
Published: 2021
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10. Author Correction: A dense ring of the trans-Neptunian object Quaoar outside its Roche limit

Author: Morgado, B. E., Sicardy, B., Braga-Ribas, F., Ortiz, J. L., Salo, H., Vachier, F., Desmars, J., Pereira, C. L., Santos-Sanz, P., Sfair, R., de Santana, T., Assafin, M., Vieira-Martins, R., Gomes-Júnior, A. R., Margoti, G., Dhillon, V. S., Fernández-Valenzuela, E., Broughton, J., Bradshaw, J., Langersek, R., Benedetti-Rossi, G., Souami, D., Holler, B. J., Kretlow, M., Boufleur, R. C., Camargo, J. I. B., Duffard, R., Beisker, W., Morales, N., Lecacheux, J., Rommel, F. L., Herald, D., Benz, W., Jehin, E., Jankowsky, F., Marsh, T. R., Littlefair, S. P., Bruno, G., Pagano, I., Brandeker, A., Collier-Cameron, A., Florén, H. G., Hara, N., Olofsson, G., Wilson, T. G., Benkhaldoun, Z., Busuttil, R., Burdanov, A., Ferrais, M., Gault, D., Gillon, M., Hanna, W., Kerr, S., Kolb, U., Nosworthy, P., Sebastian, D., Snodgrass, C., Teng, J. P., and de Wit, J.
Published: 2024
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11. A dense ring of the trans-Neptunian object Quaoar outside its Roche limit

Author: Morgado, B. E., Sicardy, B., Braga-Ribas, F., Ortiz, J. L., Salo, H., Vachier, F., Desmars, J., Pereira, C. L., Santos-Sanz, P., Sfair, R., de Santana, T., Assafin, M., Vieira-Martins, R., Gomes-Júnior, A. R., Margoti, G., Dhillon, V. S., Fernández-Valenzuela, E., Broughton, J., Bradshaw, J., Langersek, R., Benedetti-Rossi, G., Souami, D., Holler, B. J., Kretlow, M., Boufleur, R. C., Camargo, J. I. B., Duffard, R., Beisker, W., Morales, N., Lecacheux, J., Rommel, F. L., Herald, D., Benz, W., Jehin, E., Jankowsky, F., Marsh, T. R., Littlefair, S. P., Bruno, G., Pagano, I., Brandeker, A., Collier-Cameron, A., Florén, H. G., Hara, N., Olofsson, G., Wilson, T. G., Benkhaldoun, Z., Busuttil, R., Burdanov, A., Ferrais, M., Gault, D., Gillon, M., Hanna, W., Kerr, S., Kolb, U., Nosworthy, P., Sebastian, D., Snodgrass, C., Teng, J. P., and de Wit, J.
Published: 2023
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12. Pluto's lower atmosphere and pressure evolution from ground-based stellar occultations, 1988-2016

Author: Meza, E., Sicardy, B., Assafin, M., Ortiz, J. L., Bertrand, T., Lellouch, E., Desmars, J., Forget, F., Bérard, D., Doressoundiram, A., Lecacheux, J., Oliveira, J. Marques, Roques, F., Widemann, T., Colas, F., Vachier, F., Renner, S., Leiva, R., Braga-Ribas, F., Benedetti-Rossi, G., Camargo, J. I. B., Dias-Oliveira, A., Morgado, B., Gomes-Júnior, A. R., Vieira-Martins, R., Behrend, R., Tirado, A. Castro, Duffard, R., Morales, N., Santos-Sanz, P., Jelínek, M., Cunniffe, R., Querel, R., Harnisch, M., Jansen, R., Pennell, A., Todd, S., Ivanov, V. D., Opitom, C., Gillon, M., Jehin, E., Manfroid, J., Pollock, J., Reichart, D. E., Haislip, J. B., Ivarsen, K. M., LaCluyze, A. P., Maury, A., Gil-Hutton, R., Dhillon, V., Littlefair, S., Marsh, T., Veillet, C., Bath, K. -L., Beisker, W., Bode, H. -J., Kretlow, M., Herald, D., Gault, D., Kerr, S., Pavlov, H., Faragó, O., Klös, O., Frappa, E., Lavayssière, M., Cole, A. A., Giles, A. B., Greenhill, J. G., Hill, K. M., Buie, M. W., Olkin, C. B., Young, E. F., Young, L. A., Wasserman, L. H., Devogèle, M., French, R. G., Bianco, F. B., Marchis, F., Brosch, N., Kaspi, S., Polishook, D., Manulis, I., Larbi, M. Ait Moulay, Benkhaldoun, Z., Daassou, A., Azhari, Y. El, Moulane, Y., Broughton, J., Milner, J., Dobosz, T., Bolt, G., Lade, B., Gilmore, A., Kilmartin, P., Allen, W. H., Graham, P. B., Loader, B., McKay, G., Talbot, J., Parker, S., Abe, L., Bendjoya, Ph., Rivet, J. -P., Vernet, D., Di Fabrizio, L., Lorenzi, V., Magazzù, A., Molinari, E., Gazeas, K., Tzouganatos, L., Carbognani, A., Bonnoli, G., Marchini, A., Leto, G., Sanchez, R. Zanmar, Mancini, L., Kattentidt, B., Dohrmann, M., Guhl, K., Rothe, W., Walzel, K., Wortmann, G., Eberle, A., Hampf, D., Ohlert, J., Krannich, G., Murawsky, G., Gährken, B., Gloistein, D., Alonso, S., Román, A., Communal, J. -E., Jabet, F., de Visscher, S., Sérot, J., Janik, T., Moravec, Z., Machado, P., Selva, A., Perelló, C., Rovira, J., Conti, M., Papini, R., Salvaggio, F., Noschese, A., Tsamis, V., Tigani, K., Barroy, P., Irzyk, M., Neel, D., Godard, J. P., Lanoiselée, D., Sogorb, P., Vérilhac, D., Bretton, M., Signoret, F., Ciabattari, F., Naves, R., Boutet, M., De Queiroz, J., Lindner, P., Lindner, K., Enskonatus, P., Dangl, G., Tordai, T., Eichler, H., Hattenbach, J., Peterson, C., Molnar, L. A., and Howell, R. R.
Subjects: Astrophysics - Earth and Planetary Astrophysics
Abstract: Context. Pluto's tenuous nitrogen (N2) atmosphere undergoes strong seasonal effects due to high obliquity and orbital eccentricity, and has been recently (July 2015) observed by the New Horizons spacecraft. Goals are (i) construct a well calibrated record of the seasonal evolution of surface pressure on Pluto and (ii) constrain the structure of the lower atmosphere using a central flash observed in 2015. Method: eleven stellar occultations by Pluto observed between 2002 and 2016 are used to retrieve atmospheric profiles (density, pressure, temperature) between $\sim$5 km and $\sim$380 km altitude levels (i.e. pressures from about 10 microbar to 10 nanobar). Results: (i) Pressure has suffered a monotonic increase from 1988 to 2016, that is compared to a seasonal volatile transport model, from which tight constraints on a combination of albedo and emissivity of N2 ice are derived; (ii) A central flash observed on 2015 June 29 is consistent with New Horizons REX profiles, provided that (a) large diurnal temperature variations (not expected by current models) occur over Sputnik Planitia and/or (b) hazes with tangential optical depth of about 0.3 are present at 4-7 km altitude levels and/or (c) the nominal REX density values are overestimated by an implausibly large factor of about 20% and/or (d) higher terrains block part of the flash in the Charon facing hemisphere., Comment: 21 pages, 11 figures
Published: 2019
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13. The two rings of (50000) Quaoar (Corrigendum)

Author: Pereira, C. L., primary, Sicardy, B., additional, Morgado, B. E., additional, Braga-Ribas, F., additional, Fernández-Valenzuela, E., additional, Souami, D., additional, Holler, B. J., additional, Boufleur, R. C., additional, Margoti, G., additional, Assafin, M., additional, Ortiz, J. L., additional, Santos-Sanz, P., additional, Epinat, B., additional, Kervella, P., additional, Desmars, J., additional, Vieira-Martins, R., additional, Kilic, Y., additional, Gomes-Júnior, A. R., additional, Camargo, J. I. B., additional, Emilio, M., additional, Vara-Lubiano, M., additional, Kretlow, M., additional, Albert, L., additional, Alcock, C., additional, Ball, J. G., additional, Bender, K., additional, Buie, M. W., additional, Butterfield, K., additional, Camarca, M., additional, Castro-Chacón, J. H., additional, Dunford, R., additional, Fisher, R. S., additional, Gamble, D., additional, Geary, J. C., additional, Gnilka, C. L., additional, Green, K. D., additional, Hartman, Z. D., additional, Huang, C-K., additional, Januszewski, H., additional, Johnston, J., additional, Kagitani, M., additional, Kamin, R., additional, Kavelaars, J. J., additional, Keller, J. M., additional, de Kleer, K. R., additional, Lehner, M. J., additional, Luken, A., additional, Marchis, F., additional, Marlin, T., additional, McGregor, K., additional, Nikitin, V., additional, Nolthenius, R., additional, Patrick, C., additional, Redfield, S., additional, Rengstorf, A. W., additional, Reyes-Ruiz, M., additional, Seccull, T., additional, Skrutskie, M. F., additional, Smith, A. B., additional, Sproul, M., additional, Stephens, A. W., additional, Szentgyorgyi, A., additional, Sánchez-Sanjuán, S., additional, Tatsumi, E., additional, Verbiscer, A., additional, Wang, S-Y., additional, Yoshida, F., additional, Young, R., additional, and Zhang, Z-W., additional
Published: 2024
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14. The stellar occultation by (319) Leona on 13 September 2023 in preparation for the occultation of Betelgeuse

Author: Ortiz, J L, primary, Kretlow, M, additional, Schnabel, C, additional, Morales, N, additional, Flores-Martín, J, additional, González, M Sánchez, additional, Casarramona, F, additional, Selva, A, additional, Perelló, C, additional, Román-Reche, A, additional, Alonso, S, additional, Rizos, J L, additional, Gonçalves, R, additional, Castillo, A, additional, Madiedo, J M, additional, Sánchez, P Martínez, additional, Andújar, J M Fernández, additional, Maestre, J L, additional, Smith, E, additional, Gil, M, additional, Pelenjow, V, additional, Soriano, S Moral, additional, Martí, J, additional, Luque-Escamilla, P L, additional, Casas, R, additional, Casal, J Delgado, additional, Rovira, J, additional, Aceituno, F J, additional, Dekert, V, additional, Farfan, R G, additional, de Ory Guimerá, V, additional, Estepa, J Serrano, additional, Jehin, E, additional, Ferrais, M, additional, Alarcon, M R, additional, Licandro, J, additional, Serra-Ricart, M, additional, Gutiérrez, P J, additional, Kilic, Y, additional, Leiva, R, additional, Santos-Sanz, P, additional, Duffard, R, additional, Fernández-Valenzuela, E, additional, Vara-Lubiano, M, additional, Alvarez-Candal, A, additional, and Rommel, F L, additional
Published: 2023
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15. The stellar occultation by (319) Leona on 2023 September 13 in preparation for the occultation of Betelgeuse.

Author: Ortiz, J L, Kretlow, M, Schnabel, C, Morales, N, Flores-Martín, J, Sánchez González, M, Casarramona, F, Selva, A, Perelló, C, Román-Reche, A, Alonso, S, Rizos, J L, Gonçalves, R, Castillo, A, Madiedo, J M, Martínez Sánchez, P, Fernández Andújar, J M, Maestre, J L, Smith, E, and Gil, M
Subjects: *OCCULTATIONS (Astronomy), *LIGHT curves, *SMALL solar system bodies, *TIME series analysis, *ASTEROIDS, *ORBITS (Astronomy), *PHOTOMETRY
Abstract: On 2023 December 12, the star α Orionis will be occulted by asteroid (319) Leona. This represents an extraordinary and unique opportunity to analyse the brightness distribution of Betelgeuse's photosphere with extreme angular resolution by studying light curves from different points on Earth and at different wavelengths. Here we present observations of another occultation by asteroid Leona, on 2023 September 13, whose goal was to determine Leona's projected shape and size in preparation for the December 12th event and its interpretation. The occultation campaign was highly successful with 25 positive detections from 17 different sites and a near miss. The effective diameter in projected area derived from the positive detections was 66 ± 2 km using an elliptical fit to the instantaneous limb. The body is highly elongated, with dimensions of 79.6 ± 2.2 km × 54.8 ± 1.3 km in its long and short axis, respectively, at occultation time. This result, in combination with dense time series photometry of Leona that we recently obtained, together with archival sparse photometry, allowed us to predict the angular size of the asteroid for the Betelgeuse event and to simulate the expected brightness change. Also, an accurate position coming from the occultation is provided, to improve the orbit of Leona. [ABSTRACT FROM AUTHOR]
Published: 2024
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16. Changing material around (2060) Chiron revealed by an occultation on December 15, 2022

Author: Ortiz, J. L., primary, Pereira, C. L., additional, Sicardy, B., additional, Braga-Ribas, F., additional, Takey, A., additional, Fouad, A. M., additional, Shaker, A. A., additional, Kaspi, S., additional, Brosch, N., additional, Kretlow, M., additional, Leiva, R., additional, Desmars, J., additional, Morgado, B. E., additional, Morales, N., additional, Vara-Lubiano, M., additional, Santos-Sanz, P., additional, Fernández-Valenzuela, E., additional, Souami, D., additional, Duffard, R., additional, Rommel, F. L., additional, Kilic, Y., additional, Erece, O., additional, Koseoglu, D., additional, Ege, E., additional, Morales, R., additional, Alvarez-Candal, A., additional, Rizos, J. L., additional, Gómez-Limón, J. M., additional, Assafin, M., additional, Vieira-Martins, R., additional, Gomes-Júnior, A. R., additional, Camargo, J. I. B., additional, and Lecacheux, J., additional
Published: 2023
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17. Constraints on (2060) Chiron’s size, shape, and surrounding material from the November 2018 and September 2019 stellar occultations

Author: Braga-Ribas, F., primary, Pereira, C. L., additional, Sicardy, B., additional, Ortiz, J. L., additional, Desmars, J., additional, Sickafoose, A., additional, Emilio, M., additional, Morgado, B., additional, Margoti, G., additional, Rommel, F. L., additional, Camargo, J. I. B., additional, Assafin, M., additional, Vieira-Martins, R., additional, Gomes-Júnior, A. R., additional, Santos-Sanz, P., additional, Morales, N., additional, Kretlow, M., additional, Lecacheux, J., additional, Colas, F., additional, Boninsegna, R., additional, Schreurs, O., additional, Dauvergne, J. L., additional, Fernandez, E., additional, van Heerden, H. J., additional, González, H., additional, Bihel, D., additional, and Jankowsky, F., additional
Published: 2023
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18. The two rings of (50000) Quaoar

Author: Pereira, C. L., primary, Sicardy, B., additional, Morgado, B. E., additional, Braga-Ribas, F., additional, Fernández-Valenzuela, E., additional, Souami, D., additional, Holler, B. J., additional, Boufleur, R. C., additional, Margoti, G., additional, Assafin, M., additional, Ortiz, J. L., additional, Santos-Sanz, P., additional, Epinat, B., additional, Kervella, P., additional, Desmars, J., additional, Vieira-Martins, R., additional, Kilic, Y., additional, Gomes Júnior, A. R., additional, Camargo, J. I. B., additional, Emilio, M., additional, Vara-Lubiano, M., additional, Kretlow, M., additional, Albert, L., additional, Alcock, C., additional, Ball, J. G., additional, Bender, K., additional, Buie, M. W., additional, Butterfield, K., additional, Camarca, M., additional, Castro-Chacón, J. H., additional, Dunford, R., additional, Fisher, R. S., additional, Gamble, D., additional, Geary, J. C., additional, Gnilka, C. L., additional, Green, K. D., additional, Hartman, Z. D., additional, Huang, C.-K., additional, Januszewski, H., additional, Johnston, J., additional, Kagitani, M., additional, Kamin, R., additional, Kavelaars, J. J., additional, Keller, J. M., additional, de Kleer, K. R., additional, Lehner, M. J., additional, Luken, A., additional, Marchis, F., additional, Marlin, T., additional, McGregor, K., additional, Nikitin, V., additional, Nolthenius, R., additional, Patrick, C., additional, Redfield, S., additional, Rengstorf, A. W., additional, Reyes-Ruiz, M., additional, Seccull, T., additional, Skrutskie, M. F., additional, Smith, A. B., additional, Sproul, M., additional, Stephens, A. W., additional, Szentgyorgyi, A., additional, Sánchez-Sanjuán, S., additional, Tatsumi, E., additional, Verbiscer, A., additional, Wang, S.-Y., additional, Yoshida, F., additional, Young, R., additional, and Zhang, Z.-W., additional
Published: 2023
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19. A dense ring of the trans-Neptunian object Quaoar outside its Roche limit

Author: Morgado, B. E. (B. E.), Sicardy, B. (B.), Braga-Ribas, F. (F.), Ortiz, J. L. (J. L.), Salo, H. (H.), Vachier, F. (F.), Desmars, J. (J.), Pereira, C. L. (C. L.), Santos-Sanz, P. (P.), Sfair, R. (R.), de Santana, T. (T.), Assafin, M. (M.), Vieira-Martins, R. (R.), Gomes-Júnior, A. R. (A. R.), Margoti, G. (G.), Dhillon, V. S. (V. S.), Fernández-Valenzuela, E. (E.), Broughton, J. (J.), Bradshaw, J. (J.), Langersek, R. (R.), Benedetti-Rossi, G. (G.), Souami, D. (D.), Holler, B. J. (B. J.), Kretlow, M. (M.), Boufleur, R. C. (R. C.), Camargo, J. I. (J. I. B.), Duffard, R. (R.), Beisker, W. (W.), Morales, N. (N.), Lecacheux, J. (J.), Rommel, F. L. (F. L.), Herald, D. (D.), Benz, W. (W.), Jehin, E. (E.), Jankowsky, F. (F.), Marsh, T. R. (T. R.), Littlefair, S. P. (S. P.), Bruno, G. (G.), Pagano, I. (I.), Brandeker, A. (A.), Collier-Cameron, A. (A.), Florén, H. G. (H. G.), Hara, N. (N.), Olofsson, G. (G.), Wilson, T. G. (T. G.), Benkhaldoun, Z. (Z.), Busuttil, R. (R.), Burdanov, A. (A.), Ferrais, M. (M.), Gault, D. (D.), Gillon, M. (M.), Hanna, W. (W.), Kerr, S. (S.), Kolb, U. (U.), Nosworthy, P. (P.), Sebastian, D. (D.), Snodgrass, C. (C.), Teng, J. P. (J. P.), de Wit, J. (J.), Morgado, B. E. (B. E.), Sicardy, B. (B.), Braga-Ribas, F. (F.), Ortiz, J. L. (J. L.), Salo, H. (H.), Vachier, F. (F.), Desmars, J. (J.), Pereira, C. L. (C. L.), Santos-Sanz, P. (P.), Sfair, R. (R.), de Santana, T. (T.), Assafin, M. (M.), Vieira-Martins, R. (R.), Gomes-Júnior, A. R. (A. R.), Margoti, G. (G.), Dhillon, V. S. (V. S.), Fernández-Valenzuela, E. (E.), Broughton, J. (J.), Bradshaw, J. (J.), Langersek, R. (R.), Benedetti-Rossi, G. (G.), Souami, D. (D.), Holler, B. J. (B. J.), Kretlow, M. (M.), Boufleur, R. C. (R. C.), Camargo, J. I. (J. I. B.), Duffard, R. (R.), Beisker, W. (W.), Morales, N. (N.), Lecacheux, J. (J.), Rommel, F. L. (F. L.), Herald, D. (D.), Benz, W. (W.), Jehin, E. (E.), Jankowsky, F. (F.), Marsh, T. R. (T. R.), Littlefair, S. P. (S. P.), Bruno, G. (G.), Pagano, I. (I.), Brandeker, A. (A.), Collier-Cameron, A. (A.), Florén, H. G. (H. G.), Hara, N. (N.), Olofsson, G. (G.), Wilson, T. G. (T. G.), Benkhaldoun, Z. (Z.), Busuttil, R. (R.), Burdanov, A. (A.), Ferrais, M. (M.), Gault, D. (D.), Gillon, M. (M.), Hanna, W. (W.), Kerr, S. (S.), Kolb, U. (U.), Nosworthy, P. (P.), Sebastian, D. (D.), Snodgrass, C. (C.), Teng, J. P. (J. P.), and de Wit, J. (J.)
Abstract: Planetary rings are observed not only around giant planets¹, but also around small bodies such as the Centaur Chariklo² and the dwarf planet Haumea³. Up to now, all known dense rings were located close enough to their parent bodies, being inside the Roche limit, where tidal forces prevent material with reasonable densities from aggregating into a satellite. Here we report observations of an inhomogeneous ring around the trans-Neptunian body (50000) Quaoar. This trans-Neptunian object has an estimated radius⁴ of 555 km and possesses a roughly 80-km satellite⁵ (Weywot) that orbits at 24 Quaoar radii⁶,⁷. The detected ring orbits at 7.4 radii from the central body, which is well outside Quaoar’s classical Roche limit, thus indicating that this limit does not always determine where ring material can survive. Our local collisional simulations show that elastic collisions, based on laboratory experiments⁸, can maintain a ring far away from the body. Moreover, Quaoar’s ring orbits close to the 1/3 spin–orbit resonance9 with Quaoar, a property shared by Chariklo’s ²,¹⁰,¹¹ and Haumea’s³ rings, suggesting that this resonance plays a key role in ring confinement for small bodies.
Published: 2023

20. The two rings of (50000) Quaoar

Author: Ministerio de Ciencia e Innovación (España), European Commission, European Research Council, Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (Brasil), Pereira, C. L., Fernández Valenzuela, Estela del Mar, Ortiz, José Luis, Santos Sanz, Pablo, Vara-Lubiano, M., Kretlow, M., Zhang, Z. -W., Ministerio de Ciencia e Innovación (España), European Commission, European Research Council, Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (Brasil), Pereira, C. L., Fernández Valenzuela, Estela del Mar, Ortiz, José Luis, Santos Sanz, Pablo, Vara-Lubiano, M., Kretlow, M., and Zhang, Z. -W.
Abstract: Context. Quaoar is a classical trans-Neptunian object (TNO) with an area-equivalent diameter of 1100 km and an orbital semi-major axis of 43.3 astronomical units. Based on stellar occultations observed between 2018 and 2021, an inhomogeneous ring (Q1R, i.e., Quaoar’s first ring) has been detected around this body. Aims. A new stellar occultation by Quaoar was observed on August 9, 2022, with the aim of improving Quaoar’s shape models and the physical parameters of Q1R, while searching for additional material around the body. Methods. The occultation provided nine effective chords across Quaoar, pinning down its size, shape, and astrometric position. Large facilities, such as Gemini North and the Canada-France-Hawaii Telescope (CFHT), were used to obtain high acquisition rates and signal-to-noise ratios. The light curves were also used to characterize the Q1R ring (radial profiles and orbital elements). Results. Quaoar’s elliptical fit to the occultation chords yields the limb with an apparent semi-major axis of 579.5 ± 4.0 km, apparent oblateness of 0.12 ± 0.01, and area-equivalent radius of 543 ± 2 km. Quaoar’s limb orientation is consistent with Q1R and Weywot orbiting in Quaoar’s equatorial plane. The orbital radius of Q1R is refined to a value of 4057 ± 6 km. The radial opacity profile of the more opaque ring profile follows a Lorentzian shape that extends over 60 km, with a full width at half maximum (FWHM) of ∼5 km and a peak normal optical depth of 0.4. Besides the secondary events related to the already reported rings, new secondary events detected during the August 2022 occultation in three different data sets are consistent with another ring around Quaoar with a radius of 2520 ± 20 km, assuming the ring is circular and co-planar with Q1R. This new ring has a typical width of 10 km and a normal optical depth of ∼0.004. Just as Q1R, it also lies outside Quaoar’s classical Roche limit. © The Authors 2023.
Published: 2023

21. A dense ring of the trans-Neptunian object Quaoar outside its Roche limit

Author: Ministerio de Ciencia e Innovación (España), Junta de Andalucía, European Research Council, European Commission, Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (Brasil), Morgado, B. E., Ortiz, José Luis, Santos Sanz, Pablo, Kretlow, M., Duffard, René D., Morales, Nicolás, de Wit, J., Ministerio de Ciencia e Innovación (España), Junta de Andalucía, European Research Council, European Commission, Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (Brasil), Morgado, B. E., Ortiz, José Luis, Santos Sanz, Pablo, Kretlow, M., Duffard, René D., Morales, Nicolás, and de Wit, J.
Abstract: Planetary rings are observed not only around giant planets1, but also around small bodies such as the Centaur Chariklo2 and the dwarf planet Haumea3. Up to now, all known dense rings were located close enough to their parent bodies, being inside the Roche limit, where tidal forces prevent material with reasonable densities from aggregating into a satellite. Here we report observations of an inhomogeneous ring around the trans-Neptunian body (50000) Quaoar. This trans-Neptunian object has an estimated radius4 of 555 km and possesses a roughly 80-km satellite5 (Weywot) that orbits at 24 Quaoar radii6,7. The detected ring orbits at 7.4 radii from the central body, which is well outside Quaoar’s classical Roche limit, thus indicating that this limit does not always determine where ring material can survive. Our local collisional simulations show that elastic collisions, based on laboratory experiments8, can maintain a ring far away from the body. Moreover, Quaoar’s ring orbits close to the 1/3 spin–orbit resonance9 with Quaoar, a property shared by Chariklo’s2,10,11 and Haumea’s3 rings, suggesting that this resonance plays a key role in ring confinement for small bodies. © 2023, The Author(s), under exclusive licence to Springer Nature Limited.
Published: 2023

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

Author: Ministerio de Ciencia e Innovación (España), Junta de Andalucía, European Research Council, European Commission, National Research, Development and Innovation Office (Hungary), Conselho Nacional de Desenvolvimento Científico e Tecnológico (Brasil), Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (Brasil), Ministerio de Ciencia, Innovación y Universidades (España), Agencia Estatal de Investigación (España), Fondo de Inversiones de Teruel, Fernández Valenzuela, Estela del Mar, Morales, Nicolás, Vara-Lubiano, M., Ortiz, José Luis, Kretlow, M., Santos Sanz, Pablo, Alvarez-Candal, A., Duffard, René D., Casanova, V., Castro-Tirado, Alberto J., Trigo-Rodríguez, Josep María, Bretton, M., Ministerio de Ciencia e Innovación (España), Junta de Andalucía, European Research Council, European Commission, National Research, Development and Innovation Office (Hungary), Conselho Nacional de Desenvolvimento Científico e Tecnológico (Brasil), Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (Brasil), Ministerio de Ciencia, Innovación y Universidades (España), Agencia Estatal de Investigación (España), Fondo de Inversiones de Teruel, Fernández Valenzuela, Estela del Mar, Morales, Nicolás, Vara-Lubiano, M., Ortiz, José Luis, Kretlow, M., Santos Sanz, Pablo, Alvarez-Candal, A., Duffard, René D., Casanova, V., Castro-Tirado, Alberto J., Trigo-Rodríguez, Josep María, and Bretton, M.
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 GZ32. 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 ± 20 km. This diameter is ~30 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.
Published: 2023

23. Constraints on (2060) Chiron's size, shape, and surrounding material from the November 2018 and September 2019 stellar occultations

Author: European Research Council, Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (Brasil), Conselho Nacional de Desenvolvimento Científico e Tecnológico (Brasil), Fundações de Amparo à Pesquisa (Brasil), Agencia Estatal de Investigación (España), Junta de Andalucía, Braga-Ribas, F., Pereira, C. L., Sicardy, B., Ortiz, José Luis, Santos Sanz, Pablo, Morales, Nicolás, Kretlow, M., European Research Council, Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (Brasil), Conselho Nacional de Desenvolvimento Científico e Tecnológico (Brasil), Fundações de Amparo à Pesquisa (Brasil), Agencia Estatal de Investigación (España), Junta de Andalucía, Braga-Ribas, F., Pereira, C. L., Sicardy, B., Ortiz, José Luis, Santos Sanz, Pablo, Morales, Nicolás, and Kretlow, M.
Abstract: Context. After the discovery of rings around the largest known Centaur object, (10199) Chariklo, we carried out observation campaigns of stellar occultations produced by the second-largest known Centaur object, (2060) Chiron, to better characterize its physical properties and presence of material on its surroundings. Aims. We aim to provide constraints on (2060) Chiron s shape for the first time using stellar occultations. We investigate the detectability of material previously observed in its vicinity using the 2018 occultation data obtained from South Africa Astronomical Observatory (SAAO). Methods. We predicted and successfully observed two stellar occultations by Chiron. These observations were used to constrain its size and shape by fitting elliptical limbs with equivalent surface radii in agreement with radiometric measurements. We also obtained the properties of the material observed in 2011 with the same technique used to derive Chariklo s ring properties in our previous works, used to obtain limits on the detection of secondary events in our 2018 observation. Results. Constraints on the (2060) Chiron shape are reported for the first time. Assuming an equivalent radius of Requiv = 105 7+6 km, we obtained a semi-major axis of a = 126 ± 22 km. Considering Chiron? s true rotational light curve amplitude and assuming it has a Jacobi equilibrium shape, we were able to derive a 3D shape with a semi-axis of a = 126 ± 22 km, b = 109 ± 19 km, and c = 68 ± 13 km, implying in a volume-equivalent radius of Rvol= 98 ± 17 km. We determined the physical properties of the 2011 secondary events around Chiron, which may then be directly compared with those of Chariklo rings, as the same method was used. Data obtained from SAAO in 2018 do not show unambiguous evidence of the proposed rings, mainly due to the large sampling time. Meanwhile, we discarded the possible presence of a permanent ring similar to (10199) Chariklo s C1R in optical depth and extension. Conclusions. Using
Published: 2023

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

Author: Science and Technology Facilities Council (UK), European Commission, National Aeronautics and Space Administration (US), Fundação para a Ciência e a Tecnologia (Portugal), Universidad de Antofagasta, Novo Nordisk Foundation, Rożek, Agata, Kretlow, M., Science and Technology Facilities Council (UK), European Commission, National Aeronautics and Space Administration (US), Fundação para a Ciência e a Tecnologia (Portugal), Universidad de Antofagasta, Novo Nordisk Foundation, Rożek, Agata, and Kretlow, M.
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 (in a 2″ aperture) and 0.086 ± 0.003 mag day (5″) over the first week postimpact. After about 8 days postimpact we note the fading slows down to 0.057 ± 0.003 mag day (2″ aperture) and 0.068 ± 0.002 mag day (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. © 2023. The Author(s). Published by the American Astronomical Society.
Published: 2023

25. 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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26. An astrometric mass estimate for asteroid (223) Rosa

Author: Kretlow, M., primary
Published: 2022
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27. A dense ring of the trans-Neptunian object Quaoar outside its Roche limit

Author: Morgado, B E, Sicardy, B, Braga-Ribas, F, Ortiz, J L, Salo, H, Vachier, F, Desmars, J, Pereira, C L, Santos-Sanz, P, Sfair, R, de Santana, T, Assafin, M, Vieira-Martins, R, Gomes-Júnior, A R, Margoti, G, Dhillon, V S, Fernández-Valenzuela, E, Broughton, J, Bradshaw, J, Langersek, R, Benedetti-Rossi, G, Souami, D, Holler, B J, Kretlow, M, Boufleur, R C, Camargo, J I B, Duffard, R, Beisker, W, Morales, N, Lecacheux, J, Rommel, F L, Herald, D, Benz, Willy, Jehin, E, Jankowsky, F, Marsh, T R, Littlefair, S P, Bruno, G, Pagano, I, Brandeker, A, Collier-Cameron, A, Florén, H G, Hara, N, Olofsson, G, Wilson, T G, Benkhaldoun, Z, Busuttil, R, Burdanov, A, Ferrais, M, Gault, D, Gillon, M, Hanna, W, Kerr, S, Kolb, U, Nosworthy, P, Sebastian, D, Snodgrass, C, Teng, J P, de Wit, J, 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 de Mécanique Céleste et de Calcul des Ephémérides (IMCCE), 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), Institut Polytechnique des Sciences Avancées (IPSA), Joseph Louis LAGRANGE (LAGRANGE), Université Nice Sophia Antipolis (1965 - 2019) (UNS), COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de la Côte d'Azur, COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Université Côte d'Azur (UCA)-Université Côte d'Azur (UCA)-Centre National de la Recherche Scientifique (CNRS), Laboratoire d'Astrophysique de Marseille (LAM), Aix Marseille Université (AMU)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS), Science & Technology Facilities Council, University of St Andrews. St Andrews Centre for Exoplanet Science, University of St Andrews. School of Physics and Astronomy, Ministerio de Ciencia e Innovación (España), Junta de Andalucía, European Research Council, European Commission, and Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (Brasil)
Subjects: MCC, QC Physics, Multidisciplinary, [SDU]Sciences of the Universe [physics], QB Astronomy, 520 Astronomie, 3rd-DAS, 530 Physik, AC, QC, QB
Abstract: Full list of authors: Morgado, B. E.; Sicardy, B.; Braga-Ribas, F.; Ortiz, J. L.; Salo, H.; Vachier, F.; Desmars, J.; Pereira, C. L.; Santos-Sanz, P.; Sfair, R.; de Santana, T.; Assafin, M.; Vieira-Martins, R.; Gomes-Junior, A. R.; Margoti, G.; Dhillon, V. S.; Fernandez-Valenzuela, E.; Broughton, J.; Bradshaw, J.; Langersek, R.; Benedetti-Rossi, G.; Souami, D.; Holler, B. J.; Kretlow, M.; Boufleur, R. C.; Camargo, J. I. B.; Duffard, R.; Beisker, W.; Morales, N.; Lecacheux, J.; Rommel, F. L.; Herald, D.; Benz, W.; Jehin, E.; Jankowsky, F.; Marsh, T. R.; Littlefair, S. P.; Bruno, G.; Pagano, I.; Brandeker, A.; Collier-Cameron, A.; Floren, H. G.; Hara, N.; Olofsson, G.; Wilson, T. G.; Benkhaldoun, Z.; Busuttil, R.; Burdanov, A.; Ferrais, M.; Gault, D.; Gillon, M.; Hanna, W.; Kerr, S.; Kolb, U.; Nosworthy, P.; Sebastian, D.; Snodgrass, C.; Teng, J. P.; de Wit, J., Planetary rings are observed not only around giant planets1, but also around small bodies such as the Centaur Chariklo2 and the dwarf planet Haumea3. Up to now, all known dense rings were located close enough to their parent bodies, being inside the Roche limit, where tidal forces prevent material with reasonable densities from aggregating into a satellite. Here we report observations of an inhomogeneous ring around the trans-Neptunian body (50000) Quaoar. This trans-Neptunian object has an estimated radius4 of 555 km and possesses a roughly 80-km satellite5 (Weywot) that orbits at 24 Quaoar radii6,7. The detected ring orbits at 7.4 radii from the central body, which is well outside Quaoar’s classical Roche limit, thus indicating that this limit does not always determine where ring material can survive. Our local collisional simulations show that elastic collisions, based on laboratory experiments8, can maintain a ring far away from the body. Moreover, Quaoar’s ring orbits close to the 1/3 spin–orbit resonance9 with Quaoar, a property shared by Chariklo’s2,10,11 and Haumea’s3 rings, suggesting that this resonance plays a key role in ring confinement for small bodies. © 2023, The Author(s), under exclusive licence to Springer Nature Limited., This work was carried out under the Lucky Star umbrella that agglomerates the efforts of the Paris, Granada and Rio teams, which is funded by the ERC under the European Community’s H2020 (ERC grant agreement no. 669416). Part of the results were obtained using CHEOPS data. CHEOPS is an ESA mission in partnership with Switzerland with important contributions to the payload and the ground segment from Austria, Belgium, France, Germany, Hungary, Italy, Portugal, Spain, Sweden and the UK. The CHEOPS Consortium gratefully acknowledge the support received by all the agencies, offices, universities and industries involved. Their flexibility and willingness to explore new approaches were essential to the success of this mission. The design and construction of HiPERCAM was supported by the ERC under the European Union’s Seventh Framework Programme (FP/2007-2013) under ERC-2013-ADG grant agreement no. 340040 (HiPERCAM). HiPERCAM operations and V.S.D. are funded by the Science and Technology Facilities Council (grant no. ST/V000853/1). The GTC is installed at the Spanish Observatorio del Roque de los Muchachos of the Instituto de Astrofísica de Canarias, on the island of La Palma. This work has made use of data from the 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). This study was financed in part by the National Institute of Science and Technology of the e-Universe project (INCT do e-Universo, CNPq grant no. 465376/2014-2). This study was financed in part by CAPES - Finance Code 001. The following authors acknowledge the respective (1) CNPq grants to B.E.M. no. 150612/2020-6; F.B.-R. no. 314772/2020-0; R.V.-M. no. 307368/2021-1; M.A. nos. 427700/2018-3, 310683/2017-3 and 473002/2013-2; and J.I.B.C. nos. 308150/2016-3 and 305917/2019-6. (2) CAPES/Cofecub grant to B.E.M. no. 394/2016-05. (3) FAPERJ grant no. M.A. E-26/111.488/2013. (4) FAPESP (Fundação de Amparo à Pesquisa do Estado de São Paulo) grants to A.R.G.-J. no. 2018/11239-8 and R.S. no. 2016/24561-0. (5) CAPES-PrInt Program grant to G.B.-R. no. 88887.310463/2018-00, mobility number 88887.571156/2020-00. (6) DFG (the German Research Foundation) grant to R.S. no. 446102036. P.S-S. and R.D. acknowledge financial support by the Spanish grant no. AYA-RTI2018-098657-J-I00 ‘LEO-SBNAF’ (MCIU/AEI/FEDER, UE). J.L.O., P.S-S., R.D. and N.M. acknowledge financial support from the State Agency for Research of the Spanish MCIU through the ‘Center of Excellence Severo Ochoa’ award for the Instituto de Astrofísica de Andalucía (grant no. SEV-2017-0709), and they also acknowledge the financial support by the Spanish grant nos. AYA-2017-84637-R and PID2020-112789GB-I00, and the Proyectos de Excelencia de la Junta de Andalucía grant nos. 2012-FQM1776 and PY20-01309. G.B-R. and I.P. acknowledge support from CHEOPS ASI-INAF agreement no. 2019-29-HH.0. A.B. was supported by the SNSA. A.C.-C. and T.G.W. acknowledge support from STFC consolidated grant nos. ST/R000824/1 and ST/V000861/1, and UK Space Agency grant no. ST/R003203/1. U.K. and R.B. acknowledge support by The OpenSTEM Laboratories, an initiative funded by the Higher Education Funding Council for England and the Wolfson Foundation. J.W. gratefully acknowledges financial support from the Heising-Simons Foundation, C. Masson and P. A. Gilman for Artemis, the first telescope of the SPECULOOS network situated in Tenerife, Spain. The ULiege’s contribution to SPECULOOS has received funding from the ERC under the European Union’s Seventh Framework Programme (FP/2007-2013) (grant agreement no. 336480/SPECULOOS), from the Balzan Prize and Francqui Foundations, from the Belgian Scientific Research Foundation (F.R.S.-FNRS; grant no. T.0109.20), from the University of Liege and from the ARC grant for Concerted Research Actions financed by the Wallonia-Brussels Federation. TRAPPIST is a project funded by the Belgian Fonds (National) de la Recherche Scientique (F.R.S.-FNRS) under grant no. PDR T.0120.21. TRAPPIST-North is a project funded by the University of Liege, in collaboration with the Cadi Ayyad University of Marrakech (Morocco). E.J. is FNRS Senior Research Associate., With funding from the Spanish government through the "Severo Ochoa Centre of Excellence" accreditation (CEX2021-001131-S).
Published: 2023

28. 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

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

Author: Ministerio de Ciencia e Innovación (España), Junta de Andalucía, European Research Council, European Commission, Fundação para a Ciência e a Tecnologia (Portugal), Marques Oliveira, J., Ortiz, José Luis, Santos Sanz, Pablo, Morales, Nicolás, Duffard, René D., Fernández Valenzuela, Estela del Mar, Castro-Tirado, Alberto J., Kretlow, M., Casanova, V., Downs, B., Ministerio de Ciencia e Innovación (España), Junta de Andalucía, European Research Council, European Commission, Fundação para a Ciência e a Tecnologia (Portugal), Marques Oliveira, J., Ortiz, José Luis, Santos Sanz, Pablo, Morales, Nicolás, Duffard, René D., Fernández Valenzuela, Estela del Mar, Castro-Tirado, Alberto J., Kretlow, M., Casanova, V., 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 ~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. © J. Marques Oliveira et al. 2022.
Published: 2022

30. 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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31. 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

32. Refined physical parameters for Chariklo’s body and rings from stellar occultations observed between 2013 and 2020

Author: Morgado, B. E., primary, Sicardy, B., additional, Braga-Ribas, F., additional, Desmars, J., additional, Gomes-Júnior, A. R., additional, Bérard, D., additional, Leiva, R., additional, Ortiz, J. L., additional, Vieira-Martins, R., additional, Benedetti-Rossi, G., additional, Santos-Sanz, P., additional, Camargo, J. I. B., additional, Duffard, R., additional, Rommel, F. L., additional, Assafin, M., additional, Boufleur, R. C., additional, Colas, F., additional, Kretlow, M., additional, Beisker, W., additional, Sfair, R., additional, Snodgrass, C., additional, Morales, N., additional, Fernández-Valenzuela, E., additional, Amaral, L. S., additional, Amarante, A., additional, Artola, R. A., additional, Backes, M., additional, Bath, K.-L., additional, Bouley, S., additional, Buie, M. W., additional, Cacella, P., additional, Colazo, C. A., additional, Colque, J. P., additional, Dauvergne, J.-L., additional, Dominik, M., additional, Emilio, M., additional, Erickson, C., additional, Evans, R., additional, Fabrega-Polleri, J., additional, Garcia-Lambas, D., additional, Giacchini, B. L., additional, Hanna, W., additional, Herald, D., additional, Hesler, G., additional, Hinse, T. C., additional, Jacques, C., additional, Jehin, E., additional, Jørgensen, U. G., additional, Kerr, S., additional, Kouprianov, V., additional, Levine, S. E., additional, Linder, T., additional, Maley, P. D., additional, Machado, D. I., additional, Maquet, L., additional, Maury, A., additional, Melia, R., additional, Meza, E., additional, Mondon, B., additional, Moura, T., additional, Newman, J., additional, Payet, T., additional, Pereira, C. L., additional, Pollock, J., additional, Poltronieri, R. C., additional, Quispe-Huaynasi, F., additional, Reichart, D., additional, de Santana, T., additional, Schneiter, E. M., additional, Sieyra, M. V., additional, Skottfelt, J., additional, Soulier, J. F., additional, Starck, M., additional, Thierry, P., additional, Torres, P. J., additional, Trabuco, L. L., additional, Unda-Sanzana, E., additional, Yamashita, T. A. R., additional, Winter, O. C., additional, Zapata, A., additional, and Zuluaga, C. A., additional
Published: 2021
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33. Pluto's lower atmosphere and pressure evolution from ground-based stellar occultations, 1988-2016

Author: Meza, E, Sicardy, B, Assafin, M, Ortiz, JL, Bertrand, T, Lellouch, E, Desmars, J, Forget, F, Bérard, D, Doressoundiram, A, Lecacheux, J, Oliveira, JM, Roques, F, Widemann, T, Colas, F, Vachier, F, Renner, S, Leiva, R, Braga-Ribas, F, Benedetti-Rossi, G, Camargo, JIB, Dias-Oliveira, A, Morgado, B, Gomes-Júnior, AR, Vieira-Martins, R, Behrend, R, Tirado, AC, Duffard, R, Morales, N, Santos-Sanz, P, Jelínek, M, Cunniffe, R, Querel, R, Harnisch, M, Jansen, R, Pennell, A, Todd, S, Ivanov, VD, Opitom, C, Gillon, M, Jehin, E, Manfroid, J, Pollock, J, Reichart, DE, Haislip, JB, Ivarsen, KM, LaCluyze, AP, Maury, A, Gil-Hutton, R, Dhillon, V, Littlefair, S, Marsh, T, Veillet, C, Bath, K-L, Beisker, W, Bode, H-J, Kretlow, M, Herald, D, Gault, D, Kerr, S, Pavlov, H, Faragó, O, Klös, O, Frappa, E, Lavayssière, M, Cole, AA, Giles, AB, Greenhill, JG, Hill, KM, Buie, MW, Olkin, CB, Young, EF, Young, LA, Wasserman, LH, Devogèle, M, French, RG, Bianco, FB, Marchis, F, Brosch, N, Kaspi, S, Polishook, D, Manulis, I, Larbi, MAM, Benkhaldoun, Z, Daassou, A, Azhari, YE, Moulane, Y, Broughton, J, Milner, J, Dobosz, T, Bolt, G, Lade, B, Gilmore, A, Kilmartin, P, Allen, WH, Graham, PB, Loader, B, McKay, G, Talbot, J, Parker, S, Abe, L, Bendjoya, P, Rivet, J-P, Vernet, D, Fabrizio, LD, Lorenzi, V, Magazzù, A, Molinari, E, Gazeas, K, Tzouganatos, L, Carbognani, A, Bonnoli, G, Marchini, A, Leto, G, Sanchez, RZ, Mancini, L, Kattentidt, B, Dohrmann, M, Guhl, K, Rothe, W, Walzel, K, Wortmann, G, Eberle, A, Hampf, D, Ohlert, J, Krannich, G, Murawsky, G, Gährken, B, Gloistein, D, Alonso, S, Román, A, Communal, J-E, Jabet, F, Visscher, SD, Sérot, J, Janik, T, Moravec, Z, Machado, P, Selva, A, Perelló, C, Rovira, J, Conti, M, Papini, R, Salvaggio, F, Noschese, A, Tsamis, V, Tigani, K, Barroy, P, Irzyk, M, Neel, D, Godard, JP, Lanoiselée, D, Sogorb, P, Vérilhac, D, Bretton, M, Signoret, F, Ciabattari, F, Naves, R, Boutet, M, Queiroz, JD, Lindner, P, Lindner, K, Enskonatus, P, Dangl, G, Tordai, T, Eichler, H, Hattenbach, J, Peterson, C, Molnar, LA, and Howell, RR
Subjects: Earth and Planetary Astrophysics (astro-ph.EP), FOS: Physical sciences, Astrophysics - Earth and Planetary Astrophysics
Abstract: Context. Pluto's tenuous nitrogen (N2) atmosphere undergoes strong seasonal effects due to high obliquity and orbital eccentricity, and has been recently (July 2015) observed by the New Horizons spacecraft. Goals are (i) construct a well calibrated record of the seasonal evolution of surface pressure on Pluto and (ii) constrain the structure of the lower atmosphere using a central flash observed in 2015. Method: eleven stellar occultations by Pluto observed between 2002 and 2016 are used to retrieve atmospheric profiles (density, pressure, temperature) between $\sim$5 km and $\sim$380 km altitude levels (i.e. pressures from about 10 microbar to 10 nanobar). Results: (i) Pressure has suffered a monotonic increase from 1988 to 2016, that is compared to a seasonal volatile transport model, from which tight constraints on a combination of albedo and emissivity of N2 ice are derived; (ii) A central flash observed on 2015 June 29 is consistent with New Horizons REX profiles, provided that (a) large diurnal temperature variations (not expected by current models) occur over Sputnik Planitia and/or (b) hazes with tangential optical depth of about 0.3 are present at 4-7 km altitude levels and/or (c) the nominal REX density values are overestimated by an implausibly large factor of about 20% and/or (d) higher terrains block part of the flash in the Charon facing hemisphere., 21 pages, 11 figures
Published: 2019

34. Lower atmosphere and pressure evolution on Pluto from ground-based stellar occultations, 1988-2016

Author: Meza, E. Sicardy, B. Assafin, M. Ortiz, J.L. Bertrand, T. Lellouch, E. Desmars, J. Forget, F. Bérard, D. Doressoundiram, A. Lecacheux, J. Marques Oliveira, J. Roques, F. Widemann, T. Colas, F. Vachier, F. Renner, S. Leiva, R. Braga-Ribas, F. Benedetti-Rossi, G. Camargo, J.I.B. Dias-Oliveira, A. Morgado, B. Gomes-Júnior, A.R. Vieira-Martins, R. Behrend, R. Castro Tirado, A. Duffard, R. Morales, N. Santos-Sanz, P. Jelínek, M. Cunniffe, R. Querel, R. Harnisch, M. Jansen, R. Pennell, A. Todd, S. Ivanov, V.D. Opitom, C. Gillon, M. Jehin, E. Manfroid, J. Pollock, J. Reichart, D.E. Haislip, J.B. Ivarsen, K.M. LaCluyze, A.P. Maury, A. Gil-Hutton, R. Dhillon, V. Littlefair, S. Marsh, T. Veillet, C. Bath, K.-L. Beisker, W. Bode, H.-J. Kretlow, M. Herald, D. Gault, D. Kerr, S. Pavlov, H. Faragó, O. Klös, O. Frappa, E. Lavayssière, M. Cole, A.A. Giles, A.B. Greenhill, J.G. Hill, K.M. Buie, M.W. Olkin, C.B. Young, E.F. Young, L.A. Wasserman, L.H. Devogèle, M. French, R.G. Bianco, F.B. Marchis, F. Brosch, N. Kaspi, S. Polishook, D. Manulis, I. Ait Moulay Larbi, M. Benkhaldoun, Z. Daassou, A. El Azhari, Y. Moulane, Y. Broughton, J. Milner, J. Dobosz, T. Bolt, G. Lade, B. Gilmore, A. Kilmartin, P. Allen, W.H. Graham, P.B. Loader, B. McKay, G. Talbot, J. Parker, S. Abe, L. Bendjoya, P. Rivet, J.-P. Vernet, D. Di Fabrizio, L. Lorenzi, V. Magazzú, A. Molinari, E. Gazeas, K. Tzouganatos, L. Carbognani, A. Bonnoli, G. Marchini, A. Leto, G. Zanmar Sanchez, R. Mancini, L. Kattentidt, B. Dohrmann, M. Guhl, K. Rothe, W. Walzel, K. Wortmann, G. Eberle, A. Hampf, D. Ohlert, J. Krannich, G. Murawsky, G. Gährken, B. Gloistein, D. Alonso, S. Román, A. Communal, J.-E. Jabet, F. DeVisscher, S. Sérot, J. Janik, T. Moravec, Z. MacHado, P. Selva, A. Perelló, C. Rovira, J. Conti, M. Papini, R. Salvaggio, F. Noschese, A. Tsamis, V. Tigani, K. Barroy, P. Irzyk, M. Neel, D. Godard, J.P. Lanoiselée, D. Sogorb, P. Vérilhac, D. Bretton, M. Signoret, F. Ciabattari, F. Naves, R. Boutet, M. De Queiroz, J. Lindner, P. Lindner, K. Enskonatus, P. Dangl, G. Tordai, T. Eichler, H. Hattenbach, J. Peterson, C. Molnar, L.A. Howell, R.R.
Abstract: Context. The tenuous nitrogen (N2) atmosphere on Pluto undergoes strong seasonal effects due to high obliquity and orbital eccentricity, and has recently (July 2015) been observed by the New Horizons spacecraft. Aims. The main goals of this study are (i) to construct a well calibrated record of the seasonal evolution of surface pressure on Pluto and (ii) to constrain the structure of the lower atmosphere using a central flash observed in 2015. Methods. Eleven stellar occultations by Pluto observed between 2002 and 2016 are used to retrieve atmospheric profiles (density, pressure, temperature) between altitude levels of ∼5 and ∼380 km (i.e. pressures from ∼10 μbar to 10 nbar). Results. (i) Pressure has suffered a monotonic increase from 1988 to 2016, that is compared to a seasonal volatile transport model, from which tight constraints on a combination of albedo and emissivity of N2 ice are derived. (ii) A central flash observed on 2015 June 29 is consistent with New Horizons REX profiles, provided that (a) large diurnal temperature variations (not expected by current models) occur over Sputnik Planitia; and/or (b) hazes with tangential optical depth of ∼0.3 are present at 4-7 km altitude levels; and/or (c) the nominal REX density values are overestimated by an implausibly large factor of ∼20%; and/or (d) higher terrains block part of the flash in the Charon facing hemisphere. © E. Meza et al. 2019.
Published: 2019

35. Large changes in Plutoʼs atmosphere as revealed by recent stellar occultations

Author: Sicardy, B., Widemann, T., Lellouch, E., Veillet, C., Cuillandre, J.-C., Colas, F., Roques, F., Beisker, W., Kretlow, M., Lagrange, A.-M., Gendron, E., Lacombe, F., Lecacheux, J., Birnbaum, C., Fienga, A., Leyrat, C., Maury, A., Raynaud, E., Renner, S., Schultheis, M., Brooks, K., Delsanti, A., Hainaut, O. R., Gilmozzi, R., Lidman, C., Spyromilio, J., Rapaport, M., Rosenzweig, P., Naranjo, O., Porras, L., Díaz, F., Calderón, H., Carrillo, S., Carvajal, A., Recalde, E., Cavero, Gaviria L., Montalvo, C., Barría, D., Campos, R., Duffard, R., and Levato, H.
Published: 2003

36. Lower atmosphere and pressure evolution on Pluto from ground-based stellar occultations, 1988–2016

Author: Meza, E., primary, Sicardy, B., additional, Assafin, M., additional, Ortiz, J. L., additional, Bertrand, T., additional, Lellouch, E., additional, Desmars, J., additional, Forget, F., additional, Bérard, D., additional, Doressoundiram, A., additional, Lecacheux, J., additional, Oliveira, J. Marques, additional, Roques, F., additional, Widemann, T., additional, Colas, F., additional, Vachier, F., additional, Renner, S., additional, Leiva, R., additional, Braga-Ribas, F., additional, Benedetti-Rossi, G., additional, Camargo, J. I. B., additional, Dias-Oliveira, A., additional, Morgado, B., additional, Gomes-Júnior, A. R., additional, Vieira-Martins, R., additional, Behrend, R., additional, Tirado, A. Castro, additional, Duffard, R., additional, Morales, N., additional, Santos-Sanz, P., additional, Jelínek, M., additional, Cunniffe, R., additional, Querel, R., additional, Harnisch, M., additional, Jansen, R., additional, Pennell, A., additional, Todd, S., additional, Ivanov, V. D., additional, Opitom, C., additional, Gillon, M., additional, Jehin, E., additional, Manfroid, J., additional, Pollock, J., additional, Reichart, D. E., additional, Haislip, J. B., additional, Ivarsen, K. M., additional, LaCluyze, A. P., additional, Maury, A., additional, Gil-Hutton, R., additional, Dhillon, V., additional, Littlefair, S., additional, Marsh, T., additional, Veillet, C., additional, Bath, K.-L., additional, Beisker, W., additional, Bode, H.-J., additional, Kretlow, M., additional, Herald, D., additional, Gault, D., additional, Kerr, S., additional, Pavlov, H., additional, Faragó, O., additional, Klös, O., additional, Frappa, E., additional, Lavayssière, M., additional, Cole, A. A., additional, Giles, A. B., additional, Greenhill, J. G., additional, Hill, K. M., additional, Buie, M. W., additional, Olkin, C. B., additional, Young, E. F., additional, Young, L. A., additional, Wasserman, L. H., additional, Devogèle, M., additional, French, R. G., additional, Bianco, F. B., additional, Marchis, F., additional, Brosch, N., additional, Kaspi, S., additional, Polishook, D., additional, Manulis, I., additional, Ait Moulay Larbi, M., additional, Benkhaldoun, Z., additional, Daassou, A., additional, El Azhari, Y., additional, Moulane, Y., additional, Broughton, J., additional, Milner, J., additional, Dobosz, T., additional, Bolt, G., additional, Lade, B., additional, Gilmore, A., additional, Kilmartin, P., additional, Allen, W. H., additional, Graham, P. B., additional, Loader, B., additional, McKay, G., additional, Talbot, J., additional, Parker, S., additional, Abe, L., additional, Bendjoya, Ph., additional, Rivet, J.-P., additional, Vernet, D., additional, Di Fabrizio, L., additional, Lorenzi, V., additional, Magazzú, A., additional, Molinari, E., additional, Gazeas, K., additional, Tzouganatos, L., additional, Carbognani, A., additional, Bonnoli, G., additional, Marchini, A., additional, Leto, G., additional, Sanchez, R. Zanmar, additional, Mancini, L., additional, Kattentidt, B., additional, Dohrmann, M., additional, Guhl, K., additional, Rothe, W., additional, Walzel, K., additional, Wortmann, G., additional, Eberle, A., additional, Hampf, D., additional, Ohlert, J., additional, Krannich, G., additional, Murawsky, G., additional, Gährken, B., additional, Gloistein, D., additional, Alonso, S., additional, Román, A., additional, Communal, J.-E., additional, Jabet, F., additional, deVisscher, S., additional, Sérot, J., additional, Janik, T., additional, Moravec, Z., additional, Machado, P., additional, Selva, A., additional, Perelló, C., additional, Rovira, J., additional, Conti, M., additional, Papini, R., additional, Salvaggio, F., additional, Noschese, A., additional, Tsamis, V., additional, Tigani, K., additional, Barroy, P., additional, Irzyk, M., additional, Neel, D., additional, Godard, J. P., additional, Lanoiselée, D., additional, Sogorb, P., additional, Vérilhac, D., additional, Bretton, M., additional, Signoret, F., additional, Ciabattari, F., additional, Naves, R., additional, Boutet, M., additional, De Queiroz, J., additional, Lindner, P., additional, Lindner, K., additional, Enskonatus, P., additional, Dangl, G., additional, Tordai, T., additional, Eichler, H., additional, Hattenbach, J., additional, Peterson, C., additional, Molnar, L. A., additional, and Howell, R. R., additional
Published: 2019
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37. An exploration of Pluto’s environment through stellar occultations

Author: Boissel, Y., primary, Sicardy, B., additional, Roques, F., additional, Gaulme, P., additional, Doressoundiram, A., additional, Widemann, T., additional, Ivanov, V. D., additional, Marco, O., additional, Mason, E., additional, Ageorges, N., additional, Mousis, O., additional, Rousselot, P., additional, Dhillon, V. S., additional, Littlefair, S. P., additional, Marsh, T. R., additional, Assafin, M., additional, Braga Ribas, F., additional, da Silva Neto, D., additional, Camargo, J. I. B., additional, Andrei, A., additional, Vieira Martins, R., additional, Behrend, R., additional, and Kretlow, M., additional
Published: 2014
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38. Titania's radius and an upper limit on its atmosphere from the September 8, 2001 stellar occultation

Author: Widemann, T., primary, Sicardy, B., additional, Dusser, R., additional, Martinez, C., additional, Beisker, W., additional, Bredner, E., additional, Dunham, D., additional, Maley, P., additional, Lellouch, E., additional, Arlot, J.-E., additional, Berthier, J., additional, Colas, F., additional, Hubbard, W.B., additional, Hill, R., additional, Lecacheux, J., additional, Lecampion, J.-F., additional, Pau, S., additional, Rapaport, M., additional, Roques, F., additional, Thuillot, W., additional, Hills, C.R., additional, Elliott, A.J., additional, Miles, R., additional, Platt, T., additional, Cremaschini, C., additional, Dubreuil, P., additional, Cavadore, C., additional, Demeautis, C., additional, Henriquet, P., additional, Labrevoir, O., additional, Rau, G., additional, Coliac, J.-F., additional, Piraux, J., additional, Marlot, Ch., additional, Marlot, C., additional, Gorry, F., additional, Sire, C., additional, Bayle, B., additional, Simian, E., additional, Blommers, A.M., additional, Fulgence, J., additional, Leyrat, C., additional, Sauzeaud, C., additional, Stephanus, B., additional, Rafaelli, T., additional, Buil, C., additional, Delmas, R., additional, Desnoux, V., additional, Jasinski, C., additional, Klotz, A., additional, Marchais, D., additional, Rieugnié, M., additional, Bouderand, G., additional, Cazard, J.-P., additional, Lambin, C., additional, Pujat, P.-O., additional, Schwartz, F., additional, Burlot, P., additional, Langlais, P., additional, Rivaud, S., additional, Brochard, E., additional, Dupouy, Ph., additional, Lavayssière, M., additional, Chaptal, O., additional, Daiffallah, K., additional, Clarasso-Llauger, C., additional, Aloy Doménech, J., additional, Gabaldá-Sánchez, M., additional, Otazu-Porter, X., additional, Fernández, D., additional, Masana, E., additional, Ardanuy, A., additional, Casas, R., additional, Ros, J.A., additional, Casarramona, F., additional, Schnabel, C., additional, Roca, A., additional, Labordena, C., additional, Canales-Moreno, O., additional, Ferrer, V., additional, Rivas, L., additional, Ortiz, J.L., additional, Fernández-Arozena, J., additional, Martín-Rodríguez, L.L., additional, Cidadão, A., additional, Coelho, P., additional, Figuereido, P., additional, Gonçalves, R., additional, Marciano, C., additional, Nunes, R., additional, Ré, P., additional, Saraiva, C., additional, Tonel, F., additional, Clérigo, J., additional, Oliveira, C., additional, Reis, C., additional, Ewen-Smith, B.M., additional, Ward, S., additional, Ford, D., additional, Gonçalves, J., additional, Porto, J., additional, Laurindo Sobrinho, J., additional, Teodoro de Gois, F., additional, Joaquim, M., additional, Afonso da Silva Mendes, J., additional, van Ballegoij, E., additional, Jones, R., additional, Callender, H., additional, Sutherland, W., additional, Bumgarner, S., additional, Imbert, M., additional, Mitchell, B., additional, Lockhart, J., additional, Barrow, W., additional, Cornwall, D., additional, Arnal, A., additional, Eleizalde, G., additional, Valencia, A., additional, Ladino, V., additional, Lizardo, T., additional, Guillén, C., additional, Sánchez, G., additional, Peña, A., additional, Radaelli, S., additional, Santiago, J., additional, Vieira, K., additional, Mendt, H., additional, Rosenzweig, P., additional, Naranjo, O., additional, Contreras, O., additional, Díaz, F., additional, Guzmán, E., additional, Moreno, F., additional, Omar Porras, L., additional, Recalde, E., additional, Mascaró, M., additional, Birnbaum, C., additional, Cósias, R., additional, López, E., additional, Pallo, E., additional, Percz, R., additional, Pulupa, D., additional, Simbaña, X., additional, Yajamín, A., additional, Rodas, P., additional, Denzau, H., additional, Kretlow, M., additional, Valdés Sada, P., additional, Hernández, R., additional, Hernández, A., additional, Wilson, B., additional, Castro, E., additional, and Winkel, J.M., additional
Published: 2009
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39. The two Titan stellar occultations of 14 November 2003

Author: Sicardy, B., primary, Colas, F., additional, Widemann, T., additional, Bellucci, A., additional, Beisker, W., additional, Kretlow, M., additional, Ferri, F., additional, Lacour, S., additional, Lecacheux, J., additional, Lellouch, E., additional, Pau, S., additional, Renner, S., additional, Roques, F., additional, Fienga, A., additional, Etienne, C., additional, Martinez, C., additional, Glass, I. S., additional, Baba, D., additional, Nagayama, T., additional, Nagata, T., additional, Itting-Enke, S., additional, Bath, K.-L., additional, Bode, H.-J., additional, Bode, F., additional, Lüdemann, H., additional, Lüdemann, J., additional, Neubauer, D., additional, Tegtmeier, A., additional, Tegtmeier, C., additional, Thomé, B., additional, Hund, F., additional, deWitt, C., additional, Fraser, B., additional, Jansen, A., additional, Jones, T., additional, Schoenau, P., additional, Turk, C., additional, Meintjies, P., additional, Hernandez, M., additional, Fiel, D., additional, Frappa, E., additional, Peyrot, A., additional, Teng, J. P., additional, Vignand, M., additional, Hesler, G., additional, Payet, T., additional, Howell, R. R., additional, Kidger, M., additional, Ortiz, J. L., additional, Naranjo, O., additional, Rosenzweig, P., additional, and Rapaport, M., additional
Published: 2006
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40. Refined physical parameters for Chariklo’s body and rings from stellar occultations observed between 2013 and 2020

Author: Morgado, B. E., Sicardy, B., Braga-Ribas, F., Desmars, J., Gomes-Júnior, A. R., Bérard, D., Leiva, R., Ortiz, J. L., Vieira-Martins, R., Benedetti-Rossi, G., Santos-Sanz, P., Camargo, J. I. B., Duffard, R., Rommel, F. L., Assafin, M., Boufleur, R. C., Colas, F., Kretlow, M., Beisker, W., Sfair, R., Snodgrass, C., Morales, N., Fernández-Valenzuela, E., Amaral, L. S., Amarante, A., Artola, R. A., Backes, M., Bath, K.-L., Bouley, S., Buie, M. W., Cacella, P., Colazo, C. A., Colque, J. P., Dauvergne, J.-L., Dominik, M., Emilio, M., Erickson, C., Evans, R., Fabrega-Polleri, J., Garcia-Lambas, D., Giacchini, B. L., Hanna, W., Herald, D., Hesler, G., Hinse, T. C., Jacques, C., Jehin, E., Jørgensen, U. G., Kerr, S., Kouprianov, V., Levine, S. E., Linder, T., Maley, P. D., Machado, D. I., Maquet, L., Maury, A., Melia, R., Meza, E., Mondon, B., Moura, T., Newman, J., Payet, T., Pereira, C. L., Pollock, J., Poltronieri, R. C., Quispe-Huaynasi, F., Reichart, D., de Santana, T., Schneiter, E. M., Sieyra, M. V., Skottfelt, J., Soulier, J. F., Starck, M., Thierry, P., Torres, P. J., Trabuco, L. L., Unda-Sanzana, E., Yamashita, T. A. R., Winter, O. C., Zapata, A., Zuluaga, C. A., Morgado, B. E., Sicardy, B., Braga-Ribas, F., Desmars, J., Gomes-Júnior, A. R., Bérard, D., Leiva, R., Ortiz, J. L., Vieira-Martins, R., Benedetti-Rossi, G., Santos-Sanz, P., Camargo, J. I. B., Duffard, R., Rommel, F. L., Assafin, M., Boufleur, R. C., Colas, F., Kretlow, M., Beisker, W., Sfair, R., Snodgrass, C., Morales, N., Fernández-Valenzuela, E., Amaral, L. S., Amarante, A., Artola, R. A., Backes, M., Bath, K.-L., Bouley, S., Buie, M. W., Cacella, P., Colazo, C. A., Colque, J. P., Dauvergne, J.-L., Dominik, M., Emilio, M., Erickson, C., Evans, R., Fabrega-Polleri, J., Garcia-Lambas, D., Giacchini, B. L., Hanna, W., Herald, D., Hesler, G., Hinse, T. C., Jacques, C., Jehin, E., Jørgensen, U. G., Kerr, S., Kouprianov, V., Levine, S. E., Linder, T., Maley, P. D., Machado, D. I., Maquet, L., Maury, A., Melia, R., Meza, E., Mondon, B., Moura, T., Newman, J., Payet, T., Pereira, C. L., Pollock, J., Poltronieri, R. C., Quispe-Huaynasi, F., Reichart, D., de Santana, T., Schneiter, E. M., Sieyra, M. V., Skottfelt, J., Soulier, J. F., Starck, M., Thierry, P., Torres, P. J., Trabuco, L. L., Unda-Sanzana, E., Yamashita, T. A. R., Winter, O. C., Zapata, A., and Zuluaga, C. A.
Abstract: Context. The Centaur (10199) Chariklo has the first ring system discovered around a small object. It was first observed using stellar occultation in 2013. Stellar occultations allow sizes and shapes to be determined with kilometre accuracy, and provide the characteristics of the occulting object and its vicinity. Aims. Using stellar occultations observed between 2017 and 2020, our aim is to constrain the physical parameters of Chariklo and its rings. We also determine the structure of the rings, and obtain precise astrometrical positions of Chariklo. Methods. We predicted and organised several observational campaigns of stellar occultations by Chariklo. Occultation light curves were measured from the datasets, from which ingress and egress times, and the ring widths and opacity values were obtained. These measurements, combined with results from previous works, allow us to obtain significant constraints on Chariklo's shape and ring structure. Results. We characterise Chariklo's ring system (C1R and C2R), and obtain radii and pole orientations that are consistent with, but more accurate than, results from previous occultations. We confirm the detection of W-shaped structures within C1R and an evident variation in radial width. The observed width ranges between 4.8 and 9.1 km with a mean value of 6.5 km. One dual observation (visible and red) does not reveal any differences in the C1R opacity profiles, indicating a ring particle size larger than a few microns. The C1R ring eccentricity is found to be smaller than 0.022 (3σ), and its width variations may indicate an eccentricity higher than ~0.005. We fit a tri-axial shape to Chariklo's detections over 11 occultations, and determine that Chariklo is consistent with an ellipsoid with semi-axes of 143.8-1.5+1.4, 135.2-2.8+1.4, and 99.1-2.7+5.4 km. Ultimately, we provided seven astrometric positions at

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