Size, Shape, Density, and Atmospheric Limit of (50000) Quaoar Revealed from 14 years of Stellar Occultation

Margoti, Giuliano; Braga-Ribas, Felipe; Ortiz, José; Sicardy, Bruno; Desmars, Josselin; Morgado, B.E.; de Oliveira Gradovski, Eros; Pereira, Chrystian; Santos-Sanz, Pablo; Gomes-Júnior, Altair; Bueno de Camargo, Julio; 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; Alarcon, Miguel; ALİŞ, SİNAN; Alonso, Sergio; Alonso-Santiago, Javier; Amadio, Flavia; Andrade, Laerte; André, Pascal; Arcas-Silva, Jonatã; Ates, Alper; Lafuente Aznar, David; Backes, Michael; Bagiran, Mehmed; Balcar, Nelson; Barry, M.A.; Barkaoui, Khalid; Beisker, Wolfgang; Bender, Kirk; Benkhaldoun, Zouhair; Boeva, Svetlana; Bredner, Eberhard; Busuttil, Richard; Burdanov, A.Y.; Canales, Oscar; Zaragoza-Cardiel, Javier; Casanova, V.; Leal Castanheira, Matheus; Ceravolo, Peter; Conard, Steven; Negrello Correa, Luciano; Cotton, Daniel; Dhillon, V.S.; Diamond, Serena; Dumitrescu, Vlad; Dunham, Joan; Dunham, David; Duston, Christopher; Elhosseiny, Eslam; Erece, Orhan; Eryilmaz, Sila; Fernandez-García, Emilio; FİŞEK, SÜLEYMAN; Fisher, R.; Foster, Clyde; Frappa, Eric; Frasca, Antonio; Frey, Jonah; Gómez-Limón Gallardo, José; Maestre Garcia, Jose; Gault, Dave; Gazeas, Kosmas; Getrost, Kai; Gillon, Michaël; Gilmore, Alan; Glassey, Robert; Gowe, Bruce; Green, K.D.; Hanna, William; Haigh, Nicholas; Hooper, Dean; Hornoch, Kamil; Ilić, Dragana; Jacques, Cristóvão; Jankowsky, Felix; Jehin, Emmanuel; Kalkan, Selami; Kamin, Roxanne; Kaminska, Monika; Kaspi, Shai; Kavelaars, J.J.; Kerr, Stephen; Kolb, Ulrich; Komžík, Richard; Koseoglu, Dogan; Kretlow, Mike; Kuchibhotla, Sangeeta; Lecacheux, Jean; Leroy, Arnaud; Liakos, Alexios; Liberato, Luana; Lindner, Peter; Littlefair, S.P.; Madiedo, Jose; Maícas, Natalio; Malacarne, Marcio; Maley, Paul; Mánek, Jan; Marciniak, Anna; Martinez, Patrick; Iglesias-Marzoa, Ramón; McKay, Graeme; Messner, Steve; Moravec, Zdenek; Fonseca Morato, Eduardo; Neto, Messias; Newman, John; Nikitin, Vadim; Nolthenius, Richard; Nosworthy, Peter; Odeh, Mohammad; Ogloza, W.; Otken, Sibel; Özdemir, SACİT; Pál, András; Pennell, Ashley; Pereira, Amauri; Perello, Carles; Perkins, Jean; von Poschinger, Konstantin; do Prado, Thiago; Pribulla, Theodor; Rahvar, Sohrab; Ramon, Giovana; Redfield, Seth; Rinner, Claudine; Rivet, Jean-Pierre; Rodrigues, Johannes; Román-Reche, Antonio; Rommel, Flavia; de Santana, T.; Santana-Ros, T.; Selva, Antoni; Schaefer, Christoph; Scheck, Andrew; Schnabel, Carles; Schreurs, Olivier; Schweizer, Andreas; Serra-Ricart, M.; Skrutskie, Michael; Smith, Ned; Snodgrass, Colin; Sonbas, Eda; Sota, A.; Ribeiro de Sousa, Rafael; Spina, Fabio; Swift, Theodore; Szakáts, Róbert; Takey, Ali; Talafha, Mohammad; Teixeira, Ramachrisna; Terzioğlu, Zahide; Tian, Qiushi; Tsamis, Vagelis; Ülgen, Eyüp; Verbiscer, Anne; Vince, Oliver; Voelzke, Marcos; Weber, Christian; de Wit, Julien; Zejmo, Michal

doi:10.3847/1538-4357/ae907e

Size, Shape, Density, and Atmospheric Limit of (50000) Quaoar Revealed from 14 years of Stellar Occultation

Margoti G., Braga-Ribas F., Ortiz J. L., Sicardy B., Desmars J., Morgado B., ...Daha Fazla

Astrophysical Journal, cilt.1008, sa.2, 2026 (SCI-Expanded, Scopus)

Yayın Türü: Makale / Tam Makale
Cilt numarası: 1008 Sayı: 2
Basım Tarihi: 2026
Doi Numarası: 10.3847/1538-4357/ae907e
Dergi Adı: Astrophysical Journal
Derginin Tarandığı İndeksler: Science Citation Index Expanded (SCI-EXPANDED), Scopus, INSPEC, zbMATH, Directory of Open Access Journals, Academic Search Ultimate (EBSCO)
Anahtar Kelimeler: Classical Kuiper belt objects (250), Kuiper belt (893), Small Solar System bodies (1469), Stellar occultation (2135), Trans-Neptunian objects (1705)
Açık Arşiv Koleksiyonu: AVESİS Açık Erişim Koleksiyonu
Ankara Üniversitesi Adresli: Evet

Özet

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 (Formula presented) 566.1−2.2+2.5 km, and a polar semiaxis, c, of (Formula presented) 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.