1. The trans-Neptunian object (84922) 2003 VS2 through stellar occultations
- Author
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Benedetti-Rossi, Gustavo, Santos-Sanz, P., Ortiz, J. L., Assafin, M., Sicardy, B., Morales, N., Vieira-Martins, R., Duffard, R., Braga-Ribas, F., Rommel, F. L., Camargo, J. I. B., Desmars, J., Colas, A. F., Vachier, F., Alvarez-Candal, Fernández-Valenzuela, E., Almenares, L., Artola, R., Baum, T. -P., Behrend, R., Bérard, D., Bianco, F., Brosch, N., Ceretta, A., Colazo, C. A., Gomes-Junior, A. R., Ivanov, V. D., Jehin, E., Kaspi, S., Lecacheux, J., Maury, A., Melia, R., Moindrot, S., Morgado, B., Opitom, C., Peyrot, A., Pollock, J., Pratt, A., Roland, S., Spagnotto, J., Tancredi, G., Teng, J. -P., Cacella, P., Emilio, M., Feys, F., Gil-Hutton, R., Jacques, C., Machado, D. I., Malacarne, M., Manulis, I., Milone, A. C., Rojas, G., and Sfair, R.
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Astrophysics - Earth and Planetary Astrophysics - Abstract
We present results from three world-wide campaigns that resulted in the detections of two single-chord and one multi-chord stellar occultations by the Plutino object (84922) 2003~VS$_2$. From the single-chord occultations in 2013 and 2014 we obtained accurate astrometric positions for the object, while from the multi-chord occultation on November 7th, 2014, we obtained the parameters of the best-fitting ellipse to the limb of the body at the time of occultation. We also obtained short-term photometry data for the body in order to derive its rotational phase during the occultation. The rotational light curve present a peak-to-peak amplitude of 0.141 $\pm$ 0.009 mag. This allows us to reconstruct the three-dimensional shape of the body, with principal semi-axes $a = 313.8 \pm 7.1$ km, $b = 265.5^{+8.8}_{-9.8}$ km, and $c = 247.3^{+26.6}_{-43.6}$ km, which is not consistent with a Jacobi triaxial equilibrium figure. The derived spherical volume equivalent diameter of $548.3 ^{+29.5}_{-44.6}$ km is about 5\% larger than the radiometric diameter of 2003~VS$_2$ derived from Herschel data of $523 \pm 35$ km, but still compatible with it within error bars. From those results we can also derive the geometric albedo ($0.123 ^{+0.015}_{-0.014}$) and, under the assumption that the object is a Maclaurin spheroid, the density $\rho = 1400^{+1000}_{-300}$ for the plutino. The disappearances and reappearances of the star during the occultations do not show any compelling evidence for a global atmosphere considering a pressure upper limit of about 1 microbar for a pure nitrogen atmosphere, nor secondary features (e.g. rings or satellite) around the main body., Comment: 22 pages, 14 figures, 1 appendix
- Published
- 2019
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