Browsing by Author "Pereira, C. L."

Now showing 1 - 2 of 2
  • No Thumbnail Available
    Item
    Physical properties of Centaur (60558) 174P/Echeclus from stellar occultations
    (2024) Pereira, C. L.; Braga-Ribas, F.; Sicardy, B.; Gomes-Junior, A. R.; Ortiz, J. L.; Branco, H. C.; Camargo, J. I. B.; Morgado, B. E.; Vieira-Martins, R.; Assafin, M.; Benedetti-Rossi, G.; Desmars, J.; Emilio, M.; Morales, R.; Rommel, F. L.; Hayamizu, T.; Gondou, T.; Jehin, E.; Artola, R. A.; Asai, A.; Colazo, C.; Ducrot, E.; Duffard, R.; Fabrega, J.; Fernandez-Valenzuela, E.; Gillon, M.; Horaguchi, T.; Ida, M.; Kitazaki, K.; Mammana, L. A.; Maury, A.; Melita, M.; Morales, N.; Moya-Sierralta, C.; Owada, M.; Pollock, J.; Sanchez, J. L.; Santos-Sanz, P.; Sasanuma, N.; Sebastian, D.; Triaud, A.; Uchiyama, S.; Vanzi, L.; Watanabe, H.; Yamamura, H.
    The Centaur (60558) Echeclus was discovered on 2000 March 03, orbiting between the orbits of Jupiter and Uranus. After exhibiting frequent outbursts, it also received a comet designation, 174P. If the ejected material can be a source of debris to form additional structures, studying the surroundings of an active body like Echeclus can provide clues about the formation scenarios of rings, jets, or dusty shells around small bodies. Stellar occultation is a handy technique for this kind of investigation, as it can, from Earth-based observations, detect small structures with low opacity around these objects. Stellar occultation by Echeclus was predicted and observed in 2019, 2020, and 2021. We obtain upper detection limits of rings with widths larger than 0.5km and optical depth of tau = 0.02. These values are smaller than those of Chariklo's main ring; in other words, a Chariklo-like ring would have been detected. The occultation observed in 2020 provided two positive chords used to derive the triaxial dimensions of Echeclus based on a 3D model and pole orientation available in the literature. We obtained a = 37.0 +/- 0.6km, b = 28.4 +/- 0.5km, and c = 24.9 +/- 0.4km, resulting in an area-equivalent radius of 30.0 +/- 0.5km. Using the projected limb at the occultation epoch and the available absolute magnitude (), we calculate an albedo of p(v) = 0.050 +/- 0.003. Constraints on the object's density and internal friction are also proposed.
  • No Thumbnail Available
    Item
    Refined physical parameters for Chariklo's body and rings from stellar occultations observed between 2013 and 2020
    (2021) Morgado, B. E.; Sicardy, B.; Braga-Ribas, F.; Desmars, J.; Gomes-Junior, A. R.; Berard, 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.; Fernandez-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.; Jorgensen, 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.
    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.