The size, shape, density and ring of the dwarf planet Haumea from a stellar occultation
Articles > Article · 2017
Authors: J. L. Ortiz, P. Santos-Sanz, B. Sıcardy, G. Benedettı-Rossı, D. Berard, N. Morales, R. Duffard, F. Braga-Rıbas, U. Hopp, C. Rıes, V. Nascımbenı, F. Marzarı, V. Granata, A. Pal, C. Kıss, T. Prıbulla, R. Komzık, K. Hornoch, P. Pravec, P. Baccı, M. Maestrıpıerı, L. Nerlı, L. Mazzeı, M. Bachını, F. Martınellı, G. Succı, F. Cıabattarı, H. Mıkuz, A. Carbognanı, B. Gaehrken, S. Mottola, S. Hellmıch, F. L. Rommel, E. Fernandez-Valenzuela, A. Campo Bagatın, S. Cıkota, A. Cıkota, J. Lecacheux, R. Vıeıra-Martıns, J. I. B. Camargo, M. Assafin, F. Colas, R. Behrend, J. Desmars, E. Meza, A. Alvarez-Candal, W. Beısker, A. R. . Gomes-Junior, B. E. . Morgado, F. Roques, F. Vachıer, J. Berthıer, T. G. Mueller, J. M. Madiedo, Ozan ÜNSALAN, E. Sonbas, N. Karaman, O. Erece, D. T. . Koseoglu, T. Ozisik, S. Kalkan, Y. Guney, S. Niaei, O. Satir, C. Yesilyaprak, C. Puskullu, A. Kabas, O. Demircan, J. Alıkakos, V. Charmandarıs, G. Leto, J. Ohlert, J. M. Chrıstılle, R. Szakats, A. Takacsne Farkas, E. Varga-Verebelyı, G. Marton, A. Marcınıak, P. Bartczak, T. Santana-Ros, M. B. Utkıewıcz-Bak, G. Dudzınskı, V. Alı-Lagoa, K. Gazeas, L. T. Zouganatos, N. Paschalıs, V. Tsamıs, A. Sanchez-Lavega, S. Perez-Hoyos, R. Hueso, J. C. . Guırado, V. Perıs, R. Iglesıas-Marzoa
Nature, Journal Indexed in SCI Expanded, International, WoS, 2017, vol 550, pp 219-223
DOI: 10.1038/nature24051
Summary
<p>Haumea—one of the four known trans-Neptunian dwarf planets—<br /> is a very elongated and rapidly rotating body1–3. In contrast to<br /> other dwarf planets4–6, its size, shape, albedo and density are not<br /> well constrained. The Centaur Chariklo was the first body other<br /> than a giant planet known to have a ring system7, and the Centaur<br /> Chiron was later found to possess something similar to Chariklo’s<br /> rings8,9. Here we report observations from multiple Earth-based<br /> observatories of Haumea passing in front of a distant star (a multichord<br /> stellar occultation). Secondary events observed around the<br /> main body of Haumea are consistent with the presence of a ring with<br /> an opacity of 0.5, width of 70 kilometres and radius of about 2,287<br /> kilometres. The ring is coplanar with both Haumea’s equator and the<br /> orbit of its satellite Hi’iaka. The radius of the ring places it close to<br /> the 3:1 mean-motion resonance with Haumea’s spin period—that is,<br /> Haumea rotates three times on its axis in the time that a ring particle<br /> completes one revolution. The occultation by the main body provides<br /> an instantaneous elliptical projected shape with axes of about 1,704<br /> kilometres and 1,138 kilometres. Combined with rotational light curves, the occultation constrains the three-dimensional orientation<br /> of Haumea and its triaxial shape, which is inconsistent with a<br /> homogeneous body in hydrostatic equilibrium. Haumea’s largest axis<br /> is at least 2,322 kilometres, larger than previously thought, implying<br /> an upper limit for its density of 1,885 kilograms per cubic metre and a<br /> geometric albedo of 0.51, both smaller than previous estimates1,10,11.<br /> In addition, this estimate of the density of Haumea is closer to that<br /> of Pluto than are previous estimates, in line with expectations. No<br /> global nitrogen- or methane-dominated atmosphere was detected.</p>