Accurate geometric albedo, shape, and size of Hi’iaka from a stellar occultation

Stellar occultations, when a distant object passes in front of a star and casts a shadow on Earth, are a powerful tool to probe the physical properties of solar system bodies. They enable precise size and shape measurements and can reveal rings, satellites, atmospheres, or surface features. Here we present results from two stellar occultations by Hi'iaka, dwarf planet Haumea's largest satellite, observed in April 2021. The second event yielded the first documented multi-chord occultation involving a trans-Neptunian satellite other than Charon. Combining these data with photometric observations, we find that Hi'iaka is a triaxial ellipsoid with a volume-equivalent diameter of 370 ± 20 km and a density of 640 ± 80 kg/m³, indicating a porous interior. The visible geometric albedo is <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mn>0.76</mml:mn> <mml:mo>±</mml:mo> <mml:mn>0.15</mml:mn></mml:math> , (∼ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mn>30</mml:mn> <mml:mi>%</mml:mi></mml:math> higher than Haumea's). The combination of low density and rapid rotation (9.68 ± 0.02 hours), under the assumption of a homogeneous body, indicates that Hi'iaka deviates from hydrostatic equilibrium.

Authors

Institutions

Publication Details

Journal
Nature Communications
Published
2025-12-01
DOI
https://doi.org/10.1038/s41467-025-65749-1
Citations
1
Primary Topic
Astro and Planetary Science
Type
article
Field-Weighted Citation Impact
1.15

Funders

Controls
|||
ALL TIME
JAN
FEB
MAR
APR
MAY
JUN
JUL
AUG
SEP
OCT
article

Accurate geometric albedo, shape, and size of Hi’iaka from a stellar occultation

R. Gonçalves, F. Vachier, Gregory A. Feiden, Csaba Kiss et al.
1 citations
Nature Communications
Astro and Planetary Science
1.15
article

Accurate geometric albedo, shape, and size of Hi’iaka from a stellar occultation

R. Gonçalves, F. Vachier, Gregory A. Feiden, Csaba Kiss, Richard Francini, N. Morales, Zaki Grigahcene, Elizabeth Warner, B. E. Morgado, Joseph A'Hearn, Alton Luken, Hugo González, Alexander de la Vega, Marin Ferrais, A. Álvarez-Candal, R. S. Fisher, Eric Holcomb, D. B. Caton, B. Sicardy, Emmanuël Jehin, J. Licandro, R. Vieira-Martins, Bryan J. Holler, E. Fernández-Valenzuela, Jason W. Barnes, R. L. Flynn, P. Santos-Sanz, Steven M. Kreyche, M. Serra‐Ricart, J. Desmars, Artem Burdanov, A. W. Rengstorf, Z. Benkhaldoun, Bob Dunford, Joseph Froetschel, Bernie Earls, Lillian E. Mortensen, R. Duffárd, M. Kretlow, Al Ryan, Zafar Rustamkulov, William J. Miller, R. Iglesias-Marzoa, Aart M. Olsen, Wesley C. Fraser, D. Souami, R. Morales, Bill Hanna, Dennis M. Conti, M. W. Buie, S. J. Steel, Mónica Vara-Lubiano, D. Baba Aissa, M. R. Alarcón, Destin Encardes, J. I. B. Camargo, A. J. Castro‐Tirado, F. J. Galindo-Guil, András Pál, F. Braga-Ribas, F. L. Rommel, D. Monin, M. Assafin, Roxanne L. Kamin, G. Benedetti-Rossi, A. R. Gomes-Júnior, J. L. Ortiz, Emilio Fernández-García, G. Stolle-McAllister, Julien de Wit, Philip P. Langill, Gary Walker, J. Lecacheux, Thomas C. Gibson
article en
1 citations

Abstract

Stellar occultations, when a distant object passes in front of a star and casts a shadow on Earth, are a powerful tool to probe the physical properties of solar system bodies. They enable precise size and shape measurements and can reveal rings, satellites, atmospheres, or surface features. Here we present results from two stellar occultations by Hi'iaka, dwarf planet Haumea's largest satellite, observed in April 2021. The second event yielded the first documented multi-chord occultation involving a trans-Neptunian satellite other than Charon. Combining these data with photometric observations, we find that Hi'iaka is a triaxial ellipsoid with a volume-equivalent diameter of 370 ± 20 km and a density of 640 ± 80 kg/m³, indicating a porous interior. The visible geometric albedo is <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mn>0.76</mml:mn> <mml:mo>±</mml:mo> <mml:mn>0.15</mml:mn></mml:math> , (∼ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mn>30</mml:mn> <mml:mi>%</mml:mi></mml:math> higher than Haumea's). The combination of low density and rapid rotation (9.68 ± 0.02 hours), under the assumption of a homogeneous body, indicates that Hi'iaka deviates from hydrostatic equilibrium.

Nature CommunicationsVol. 16(1)
Eötvös Loránd University (HU), University of Central Florida (US), Cadi Ayyad University (MA), Herzberg Institute of Astrophysics (CA), Universidade Tecnológica Federal do Paraná (BR), Southwest Research Institute (US), Centre National de la Recherche Scientifique (FR), Space Telescope Science Institute (US), University of Alicante (ES), Planetary Science Institute (US), Johns Hopkins University (US), University of Namur (BE), University of Idaho (US), University of Liège (BE), University of Calgary (CA), University of Oregon (US), American Association of Variable Star Observers (US), Université Paris Cité (FR), University of Victoria (CA), Université Paris Sciences et Lettres (FR), Oregon Department of Education (US), Observatoire de Paris (FR), Maria Mitchell Association (US), Konkoly Observatory (HU), American Occupational Therapy Association (US), Digital Hollywood University (JP), Sorbonne Université (FR), Valongo Observatory (BR), Sorbonne Paris Cité (FR), Ministério da Ciência e Tecnologia (AO), Fundación Marques de Valdecilla (ES), Laboratoire d’études spatiales et d’instrumentation en astrophysique (FR), Centro de Estudios de Física del Cosmos de Aragón (ES), National Observatory (BR), Instituto Politécnico de Tomar (PT), Observatoire de la Côte d’Azur (FR), Instituto de Astrofísica de Canarias (ES), Centre de Recherche en Astronomie Astrophysique et Géophysique (DZ), Purdue University Northwest (US), Laboratório Interinstitucional de e-Astronomia (BR), Instituto de Astrofísica de Andalucía (ES), Appalachian State University (US), Universidade Federal do Paraná (BR), Institut de Mécanique Céleste et de Calcul des Éphémérides (FR), Institut Polytechnique des Sciences Avancées (FR), University of Baltimore (US), University of Maryland, College Park (US), Universidade Federal de Uberlândia (BR), Universidade Estadual Paulista (Unesp) (BR), University of North Georgia (US)
National Aeronautics and Space Administration, Coordenação de Aperfeiçoamento de Pessoal de Nível Superior, Fonds De La Recherche Scientifique - FNRS, Conselho Nacional de Desenvolvimento Científico e Tecnológico, Nuclear Safety and Security Commission, Fundação Carlos Chagas Filho de Amparo à Pesquisa do Estado do Rio de Janeiro, Junta de Andalucía, Nemzeti Kutatási Fejlesztési és Innovációs Hivatal, Instituto de Astrofísica de Andalucía, Smithsonian Astrophysical Observatory, Consejo Superior de Investigaciones Científicas, Agencia Estatal de Investigación, National Research, Development and Innovation Office
Openalex Percentile: Top 15%
Astro and Planetary Science
1.15
DOIOpen Access PDFOpenAlex
AI Navigator

Ask Laika to Summarize, Analyze, and Connect papers live on the map.

Summarize Papers & Methodologies

Extract key findings, datasets, and comparative methods across publications.

Benchmark Rankings & Visual Analytics

Rank top research institutions, authors, funders, topics, and journals by Field-Weighted Citation Impact (FWCI) and paper volume with instant charts.

Connect Distant Disciplines

Bridge topological clusters on the map to find hidden collaborative intersections.