Bibcode
Margoti, Giuliano; Braga-Ribas, Felipe; Ortiz, José Luis; Sicardy, Bruno; Desmars, Josselin; Morgado, B. E.; de Oliveira Gradovski, Eros; Pereira, Chrystian Luciano; Santos-Sanz, Pablo; Gomes-Júnior, Altair Ramos; Bueno de Camargo, Julio Ignacio; Assafin, Marcelo; Vieira-Martins, Roberto; Kilic, Yucel; Souami, Damya; Duffard, René; Benedetti-Rossi, Gustavo; Pinheiro, Tiago; Poiani, Maísa; Rondón, Eduardo; Marcelo, Emilio; Herald, Dave; Sfair, Rafael; Morales, Nicolas; Colas, Francois; Vachier, Frédéric; Vara Lubiano, Mónica; Boufleur, Rodrigo; Acar, Mert; Aceituno, Francisco J.; Alarcon, Miguel R.; Alis, Sinan; Alonso, Sergio; Alonso-Santiago, Javier; Amadio, Flavia; Andrade, Laerte; André, Pascal; Arcas-Silva, Jonatã; Ates, Alper K.; Lafuente Aznar, David; Backes, Michael; Bagiran, Mehmed Naim; Balcar, Nelson; Barry, M. A.; Barkaoui, Khalid; Beisker, Wolfgang; Bender, Kirk; Benkhaldoun, Zouhair; Boeva, Svetlana; Bredner, Eberhard H. R.; Busuttil, Richard; Burdanov, A. Y.; Canales, Oscar; Zaragoza-Cardiel, Javier; Casanova, V.; Leal Castanheira, Matheus; Ceravolo, Peter; Conard, Steven J.; Negrello Correa, Luciano; Cotton, Daniel V.; Dhillon, V. S.; Diamond, Serena; Dumitrescu, Vlad; Dunham, Joan; Dunham, David W.; Duston, Christopher L.; Elhosseiny, Eslam; Erece, Orhan; Eryilmaz, Sila; Fernandez-García, Emilio J.; Fisek, Suleyman; Fisher, R. Scott; Foster, Clyde; Frappa, Eric; Frasca, Antonio; Frey, Jonah; Gómez-Limón Gallardo, José María; Maestre Garcia, Jose Luis; Gault, Dave; Gazeas, Kosmas; Getrost, Kai; Gillon, Michaël; Gilmore, Alan; Glassey, Robert; Gowe, Bruce; Green, K. D.; Hanna, William; Haigh, Nicholas J.; Hooper, Dean; Hornoch, Kamil; Ilić, Dragana; Jacques, Cristóvão; Jankowsky, Felix; Jehin, Emmanuel; Kalkan, Selami; Kamin, Roxanne; Kaminska, Monika K.; Kaspi, Shai; Kavelaars, J. J.; Kerr, Stephen et al.
Bibliographical reference
The Astrophysical Journal
Advertised on:
9
2026
Journal
Citations
2
Refereed citations
0
Description
We present results from 28 stellar occultations by the large trans-Neptunian object (50000) Quaoar registered between 2018 and 2025. By performing a joint analysis of this occultation dataset, along with nine other published events, we were able to fit an oblate ellipsoid shape, with equatorial semiaxes a and b of 566.1-2.2+2.5 km, and a polar semiaxis, c, of 511.2-3.7+3.6 km. It provides an equivalent volumetric diameter of 1094.4 ± 4.6 km and polar oblateness of 0.097 ± 0.011. Considering an absolute magnitude of H = 2.79 ± 0.35, we derive a geometric albedo of pV = 0.125 ± 0.038. We have derived new upper limits to the surface pressure of a CH4 atmosphere of 0.15 nbar (1σ) and 0.65 nbar (3σ). We also provide a table with the 36 new astrometric positions for Quaoar. Using the new system mass derived from Weywot's orbit around Quaoar, we calculated a density of 1.760 ± 0.109 g cm-3. Moreover, from the derived size and rotation period (8.8394 ± 0.0002 hr, we calculated that, if Quaoar is in Maclaurin hydrostatic equilibrium state, it would have a density of 1.859 ± 0.200 g cm-3. This result, within the error bars, is compatible with the value we found. Therefore, this work shows that Quaoar can be a Maclaurin object, being eligible as a dwarf planet.