# 10 Hygiea <!-- SOLSIM:BEGIN g31 — Solar System explorer state (hand-built on wt-core, specs/solar/); do not hand-edit inside --> **Microsim — three.js (Wikitube framework):** *10 Hygiea in the Solar System explorer* <div class="wt-sim" data-src="https://wikitube-3d-microsims.netlify.app/solar/Solar_System.html?obj=Hygiea&embed=1" data-title="10 Hygiea in the Solar System explorer"></div> *The Solar System explorer locked on this article's state (`?obj=Hygiea`); every object and population of the [[PORTAL_Solar_System|Solar System portal]] has its own state in the same scene.* <!-- SOLSIM:END --> *Try: press l to label the bodies and find Hygiea in the outer belt, noticeably closer to Jupiter than Ceres; set the speed to 1 year/s and watch it take about five and a half seconds per orbit, longest of the large asteroids; drag to an edge-on view and compare its nearly flat path with the steep tilt of Pallas.* **Hygiea** (minor-planet designation **10 Hygiea**) is the fourth-largest body in the [[Asteroid_belt|asteroid belt]] and the largest in its outer part, with a mean diameter of about 433 km.[^vernazza2021][^demeo2015] Annibale de Gasparis discovered it at Naples on 12 April 1849, the tenth [[Asteroid|asteroid]] found, and it is named after Hygieia, the Greek goddess of health.[^ashworth2022][^gargano2023] It holds about 3% of the belt's mass and roughly a tenth of the mass of [[Ceres_(dwarf_planet)|Ceres]], which it resembles closely in its dark, carbon-rich and water-altered surface.[^demeo2013][^rivkin2025] Adaptive-optics images from the Very Large Telescope show Hygiea to be almost spherical, with only two clearly identified large craters. Vernazza and colleagues explain the shape as the result of a giant impact that shattered the body two to three billion years ago; the debris reassembled into a near-fluid sphere, and the fragments that escaped form the Hygiea family of more than 7,000 asteroids.[^vernazza2020][^carruba2014][^eso2019] Because of that shape, Hygiea has been proposed as a possible [[Dwarf_planet|dwarf planet]], though the International Astronomical Union has not classified it as one.[^eso2019] The explorer at the top of this page is locked on Hygiea, shown on its catalogued orbit in the outer belt a little over 3.1 [[Astronomical_unit|AU]] from the [[Sun]]; its 433 km disc is enlarged by the log size law.[^jpl-hygiea][^jpl-sbdb] ## History ### Discovery De Gasparis was mapping stars along the [[Ecliptic|ecliptic]] down to about 14th magnitude with the Capodimonte Observatory's Reichenbach equatorial when, on 12 April 1849, he found a star of magnitude 9–10 that was missing from the Berlin Academy's star chart.[^gargano2023] Bad weather delayed confirmation, but by 14 and 17 April he could see that it had moved, and he concluded that it was a new planet between [[Mars]] and [[Jupiter]].[^gargano2023][^hind1852] The news travelled through Rome to Heinrich Christian Schumacher, who published it in *Astronomische Nachrichten* in May 1849.[^ashworth2022] Hygiea was de Gasparis's first discovery; he found another six asteroids in 1850–1853 and two more in the 1860s.[^ashworth2022] ### Name De Gasparis left the choice of name to his friend Ernesto Capocci, director of the observatory, who proposed Igea, the Italian form of Hygieia. De Gasparis added "Borbonica" in honour of Ferdinand II of the Two Sicilies, the observatory's patron, and the two sent the name "Igea Borbonica" to the king on 8 May 1849.[^gargano2023][^palma2019] The tribute may have helped them avoid punishment for their part in the liberal movements of 1848.[^mancuso1988] In England, John Herschel proposed Parthenope, after the siren who founded Naples, and Schumacher objected to the Italian spelling; de Gasparis later gave Herschel's name to his next discovery, 11 Parthenope, in 1850.[^palma2019][^ashworth2022] Early astronomers often wrote the name Hygeia, but Hygiea became standard by the 1860s, and John Russell Hind noted that "Borbonica" had been dropped by 1852.[^hind1852][^palma2019] ### Symbol and designation In a letter to Hind of November 1850, de Gasparis described Hygiea's symbol as a serpent shaped like a Greek zeta crowned with a star, the serpent being an attribute of the goddess.[^degasparis1850][^bala2023] It arrived too late for the almanacs, which listed Hygiea without a symbol, and Benjamin Apthorp Gould reinterpreted it in 1852 as a rod of Asclepius.[^gould1852][^bala2023] Individual symbols were soon abandoned in favour of numbers, first in a circle and later in parentheses, giving the modern forms (10) Hygiea and 10 Hygiea.[^hilton2001][^mpc-hygiea] The Minor Planet Center also lists the retrospective provisional designations A849 GA, for the discovery, and A900 GA, for a chance photographic record made at Arequipa, Peru, in 1900.[^mpc-hygiea][^mpc-desig] ### Classification Unlike the first four asteroids, Hygiea was found when the category was already shifting; within a few years of its discovery it was being called a minor planet or an asteroid rather than a planet.[^hilton2001][^hind1852] During the drafting of a planet definition in 2006, the IAU committee considered that Hygiea might fall among the planets or dwarf planets if it proved to be in hydrostatic equilibrium.[^gingerich2006] The adopted definition requires a dwarf planet to be round but not to have cleared its neighbourhood. When VLT images revealed Hygiea's shape in 2019, Vernazza and collaborators argued that it could qualify and, if so, would be the smallest known dwarf planet.[^eso2019][^vernazza2020] ## Orbit Hygiea orbits at a mean distance of about 3.14 AU with a period of 5.57 years. Its [[Orbit|orbit]] is moderately elliptical, taking it from 2.79 AU at perihelion to 3.49 AU at aphelion, and is inclined only 3.8° to the ecliptic.[^jpl-hygiea] By [[Kepler's_laws_of_planetary_motion|Kepler's third law]], 3.14^1.5 ≈ 5.56 years (derived). It never comes closer than about 1.24 AU to [[Mars]] or 1.54 AU to [[Jupiter]].[^mpc-hygiea] Hygiea sits in a three-body mean-motion resonance with Jupiter and [[Saturn]], a relation in which a combination of the three bodies' orbital frequencies with small integer coefficients adds to zero.[^nesvorny1998] Such resonances make an orbit chaotic: simulations give Hygiea a Lyapunov time of about 14,000–16,000 years, the timescale over which small uncertainties in its position grow by a factor of e, although the orbit stays within the same region over much longer times.[^nesvorny1998][^sidlichovsky1999] Šidlichovský describes such orbits as examples of "stable chaos": formally [[Chaos_theory|chaotic]], yet confined to the same region of the belt over long times.[^sidlichovsky1999] Other asteroids occasionally pass near enough for Hygiea's [[Gravity|gravity]] to bend their paths measurably, which is how its mass is determined. Galád and Gray identified 40 asteroids that came within 0.05 AU of it between 1970 and 2000.[^galad2002] Over 30 million years, repeated encounters with Hygiea can shift the proper semi-major axes of nearby asteroids by about 0.0009 AU.[^carruba2013a] ## Hygiea family Hygiea is the parent of the Hygiea family, the largest family in the outer belt, with more than 7,000 known members sharing similar orbits and spectra.[^eso2019][^carruba2013b] Carruba and colleagues date the family to about 2–3 billion years ago from the dynamical spreading of its members' orbits.[^carruba2014] The impact that formed it ejected at least 1.7% of Hygiea's original mass and was probably caused by a body 75–150 km across, yet Hygiea still holds more than 98% of the family's mass.[^vernazza2020] A striking feature is that the collision left no giant basin. On [[4_Vesta|Vesta]], impacts of comparable scale produced the Rheasilvia and Veneneia basins; on Hygiea, simulations by Vernazza and colleagues instead show the body shattering completely and its fragments reassembling into a sphere.[^vernazza2020] The family therefore records an event that destroyed the old surface of its parent. Similar reassembled, roughly spherical parents have been proposed for other large family-forming asteroids, including 8 Flora and 31 Euphrosyne.[^vernazza2021] Spectroscopic surveys of the outer belt find that family members share Hygiea's dark, primitive spectrum.[^depra2020] ## Rotation Hygiea rotates once every 13.83 hours (13 h 49.5 min), a period determined only recently.[^ferrais2021][^vernazza2020] Measurements from the 1950s onward had given about 18 hours, and studies from 1991 onward about 27.6 hours, roughly double the true value, because sparse light-curve data could be fitted by the wrong period.[^groeneveld1954][^michalowski1991][^ferrais2021] Imaging with VLT/SPHERE in 2017–2018, supported by new photometry with the TRAPPIST telescopes, settled the question.[^ferrais2021] Hygiea's brightness varies by up to about 15% as it rotates, driven by surface albedo features rather than by an elongated shape.[^ferrais2021][^vernazza2020] The north pole points toward ecliptic longitude 306° and latitude −29°, which gives an obliquity of about 120°. Because this exceeds 90°, Hygiea rotates in the retrograde sense relative to its orbit.[^vernazza2021] Its day is also long compared with the 5–9-hour spins of [[4_Vesta|Vesta]], [[2_Pallas|Pallas]] and [[Ceres_(dwarf_planet)|Ceres]].[^vernazza2021] ## Size and mass Hygiea is the fourth-largest main-belt asteroid in both volume and mass: its volume-equivalent diameter is 433 ± 8 km and its mass about 8.74 × 10¹⁹ kg.[^vernazza2021] That is less than half [[Ceres_(dwarf_planet)|Ceres]]'s diameter and about 9% of its mass (derived), and about 3% of the belt's total. Together, Ceres, Vesta, Pallas and Hygiea account for a little over half of the belt's mass.[^demeo2013] These four are sometimes called the "Big Four", although the term once referred to the first four asteroids discovered.[^rivkin2011][^cunningham2021] Its surface [[Gravity|gravity]] is roughly 0.12 m/s² (derived from G, M and R).[^openstax] Hygiea's rank was not recognised until 1974, when David Morrison derived its diameter and albedo from its infrared thermal emission and showed that its dark surface had hidden its size.[^morrison1974] Its mass comes from deflections of passing asteroids. The first such estimate, in 1987, used the close approach of 829 Academia, which passed within 0.006 AU of Hygiea in May 1927; later values drew on many more encounters and better astrometry.[^scholl1987][^michalak2001][^goffin2014] ## Geology ### Shape, craters, and topography Hygiea is nearly spherical, with dimensions of about 450 × 430 × 424 km (±10 km on the equatorial axes, ±20 km on the polar axis), second only to [[Ceres_(dwarf_planet)|Ceres]] in roundness among main-belt asteroids.[^vernazza2020][^vernazza2021] Its polar flattening and spin match a Maclaurin spheroid, the equilibrium shape of a rotating self-gravitating fluid, which is the basis for proposing it as a dwarf planet.[^vernazza2020] Only two craters are confidently identified, about 180 km and 97 km across, both with central peaks. The discoverers informally named them Serpens and Calix, Latin for "snake" and "cup", after the attributes of Hygieia; the names are not approved by the IAU.[^vernazza2020] No bowl-shaped crater larger than about 30 km is visible. As on Ceres, flat-floored craters may be common but hard to see from Earth, which would point to an ice-rich subsurface that allows topography to relax.[^vernazza2020] The modelled impact melted the body into a fluid-like state, and the present shape suggests that it had solidified within about four hours.[^vernazza2020] ### Surface The surface is dark, with a geometric albedo of about 6–7%. Its brightest spot, in the southern hemisphere, is only about 10% brighter than average, and the albedo pattern resembles that of Ceres.[^vernazza2020][^vernazza2021] Temperatures reach about 230 K at the subsolar point, and the average ranges from about 150 to 180 K between perihelion and aphelion.[^barucci2002][^lim2005][^rivkin2014] Submillimetre and microwave observations indicate a fine, dusty regolith of low thermal inertia at least 8 cm deep, possibly finer than the soil of the [[Moon]].[^lebofsky1985][^johnston1989] Spectrally Hygiea is a C-type asteroid.[^barucci2002] Its surface consists of hydrated and ammoniated phyllosilicates and carbonates, with hints of [[Water|water]] ice. The James Webb Space Telescope's NIRSpec finds magnesium-rich clays consistent with ammoniated saponite and a spectrum so close to Ceres's that Hygiea has been called its "virtual spectral twin".[^rivkin2025][^depra2020] Both resemble CM carbonaceous chondrites, [[Carbon|carbon]]-rich primitive meteorites that saw little heating but some alteration by water.[^rivkin2025][^barucci2002] Ground-based spectra vary over time. Busarev reported shifts among C, B and F types as Hygiea rotated, and Rivkin and colleagues found changes over years in a 3.1-micrometre absorption that could come from ammoniated minerals, hydrated minerals or water frost.[^busarev2011][^rivkin2019] ### Density and interior Estimates of the bulk density are 1.94 g/cm³ (2020) and 2.06 g/cm³ (2021), close to Ceres's 2.16 g/cm³.[^vernazza2020][^vernazza2021] The density, the hints of ice and the scarcity of fresh bowl-shaped craters together suggest an ice-rich subsurface, and some authors consider the interior possibly differentiated.[^vernazza2020][^hanus2017] Vernazza and colleagues note that at the higher density Hygiea would rank among the denser large C-type asteroids, perhaps because extensive aqueous alteration compacted its interior.[^vernazza2021] ## Observation and exploration ### Observation Hygiea's dark surface and outer-belt orbit make it faint. It is the third-dimmest of the first 23 asteroids discovered, which is why six smaller asteroids were found before it.[^odeh] At typical oppositions it reaches magnitude +10.2, beyond binoculars, but at a perihelic opposition it can reach +9.1, within range of 10 × 50 binoculars.[^odeh][^ford2017] Seventeen stellar occultations by Hygiea had been recorded by 2018, including well-observed events in 2002 and 2014, and they have helped constrain its size, shape and spin axis.[^watanabe2018][^hanus2017] Hubble imaging excluded any companion larger than about 16 km.[^storrs1999] ### Exploration No spacecraft has visited Hygiea. In 2006 Mark Sykes and colleagues at the Planetary Science Institute proposed Exploring the Very Earliest Epoch (EVE), a Discovery-class mission that would have sent a copy of the Dawn spacecraft to rendezvous with Hygiea in 2021; it was not selected.[^sykes2006] In the 2010s Pierre Vernazza and Philippe Lamy proposed INSIDER to ESA, a mission to orbit two or three large primitive asteroids and deploy landers, with Hygiea and 24 Themis among its candidate targets; it too was not approved.[^vernazza2014][^ulivi2014] Such missions are motivated by the idea that primitive outer-belt bodies preserve clues to the origin of [[Earth]]'s water and to the early [[Formation_and_evolution_of_the_Solar_System|formation of the Solar System]].[^vernazza2014][^sykes2006] ## See also - [[Asteroid_belt]] · [[Asteroid]] - [[Ceres_(dwarf_planet)]] · [[4_Vesta]] · [[2_Pallas]] - [[Dwarf_planet]] · [[IAU_definition_of_planet]] - 704 Interamnia, the fifth-largest main-belt asteroid, also close to an equilibrium shape - Hygiea family ## Notes The orbital period check, the mass relative to Ceres and the surface gravity are derived from the cited values and rounded. ## References [^vernazza2021]: Vernazza, P.; Ferrais, M.; Jorda, L.; et al. (2021). "VLT/SPHERE imaging survey of the largest main-belt asteroids: final results and synthesis". *Astronomy & Astrophysics* 654: A56. https://doi.org/10.1051/0004-6361/202141781 [^demeo2015]: DeMeo, F. E.; Alexander, C. M. O'D.; Walsh, K. J.; Chapman, C. R.; Binzel, R. P. (2015). "The compositional structure of the asteroid belt". In Michel, P.; DeMeo, F. E.; Bottke, W. F. (eds.), *Asteroids IV*. University of Arizona Press, pp. 13–41. https://doi.org/10.2458/azu_uapress_9780816532131-ch002 [^ashworth2022]: Ashworth, W. B. (9 November 2022). "Scientist of the day: Annibale de Gasparis". Linda Hall Library. https://www.lindahall.org/about/news/scientist-of-the-day/annibale-de-gasparis/ [^gargano2023]: Gargano, M. (2023). "Annibale de Gasparis, the sublime calculator of Parthenope's sky". *Bulletin of Regional Natural History* 3: 1–24. [^demeo2013]: DeMeo, F. E.; Carry, B. (2013). "The taxonomic distribution of asteroids from multi-filter all-sky photometric surveys". *Icarus* 226: 723–741. https://doi.org/10.1016/j.icarus.2013.06.027 [^rivkin2025]: Rivkin, A. S.; Thomas, C. A.; Wong, I.; et al. (2025). "Observations and quantitative compositional analysis of Ceres, Pallas, and Hygiea using JWST/NIRSpec". *The Planetary Science Journal* 6: 9. https://doi.org/10.3847/PSJ/ad944c [^vernazza2020]: Vernazza, P.; Jorda, L.; Ševeček, P.; et al. (2020). "A basin-free spherical shape as an outcome of a giant impact on asteroid Hygiea". *Nature Astronomy* 4: 136–141 (including Supplementary Information). https://doi.org/10.1038/s41550-019-0915-8 [^carruba2014]: Carruba, V.; Domingos, R. C.; Huaman, M. E.; dos Santos, C. R.; Souami, D. (2014). "Dynamical evolution and chronology of the Hygiea asteroid family". *Monthly Notices of the Royal Astronomical Society* 437: 2279–2290. https://doi.org/10.1093/mnras/stt2040 [^eso2019]: European Southern Observatory (28 October 2019). "ESO telescope reveals what could be the smallest dwarf planet yet in the Solar System" (release eso1918). https://www.eso.org/public/news/eso1918/ [^jpl-hygiea]: JPL Solar System Dynamics. "Small-Body Database Lookup: 10 Hygiea" (elements fetched 2026-09-18). https://ssd.jpl.nasa.gov/tools/sbdb_lookup.html#/?sstr=10 [^jpl-sbdb]: JPL Solar System Dynamics. "Small-Body Database Lookup" (elements fetched 2026-09-18). https://ssd.jpl.nasa.gov/tools/sbdb_lookup.html [^hind1852]: Hind, J. R. (1852). *The Solar System: A Descriptive Treatise upon the Sun, Moon, and Planets*. G. P. Putnam, p. 126. https://archive.org/details/solarsystemdescr00hind/page/126/mode/2up [^palma2019]: Palma, P. (5 November 2019). "A Parthenope in the sky". The Royal Society. https://royalsociety.org/blog/2019/11/a-parthenope-in-the-sky/ [^mancuso1988]: Mancuso, S. (1988). "De Gasparis, Annibale". *Dizionario Biografico degli Italiani* 36. Istituto della Enciclopedia Italiana. https://www.treccani.it/enciclopedia/annibale-de-gasparis_(Dizionario-Biografico) [^degasparis1850]: de Gasparis, A. (1850). "De Gasparis' new planet" (letter to Mr Hind). *Monthly Notices of the Royal Astronomical Society* 11: 1–2. https://doi.org/10.1093/mnras/11.1.1a [^bala2023]: Bala, G. J.; Miller, K. (18 September 2023). "Unicode request for historical asteroid symbols". Unicode Consortium, L2/23-207. https://www.unicode.org/L2/L2023/23207-historical-asteroids.pdf [^gould1852]: Gould, B. A. (1852). "On the symbolic notation of the asteroids". *The Astronomical Journal* 2: 80. https://doi.org/10.1086/100212 [^hilton2001]: Hilton, J. L. (2001, revised 2007). "When did the asteroids become minor planets?". US Naval Observatory. https://aa.usno.navy.mil/faq/minorplanets [^mpc-hygiea]: IAU Minor Planet Center. "(10) Hygiea = A849 GA = A900 GA". https://www.minorplanetcenter.net/db_search/show_object?object_id=10 [^mpc-desig]: IAU Minor Planet Center. "New- and old-style minor planet designations". https://www.minorplanetcenter.net/iau/info/DesDoc.html [^gingerich2006]: Gingerich, O. (12 August 2006). "Planet definition Q & A factsheet". *Dissertatio cum Nuncio Sidereo III*, IAU General Assembly newspaper, p. 17. https://www.iau.org/static/publications/ga_newspapers/20060812.pdf [^nesvorny1998]: Nesvorný, D.; Morbidelli, A. (1998). "Three-body mean motion resonances and the chaotic structure of the asteroid belt". *The Astronomical Journal* 116: 3029–3037. https://doi.org/10.1086/300632 [^sidlichovsky1999]: Šidlichovský, M. (1999). "On stable chaos in the asteroid belt". *Celestial Mechanics and Dynamical Astronomy* 73: 77–86. https://doi.org/10.1023/A:1008330610152 [^galad2002]: Galád, A.; Gray, B. (2002). "Asteroid encounters suitable for mass determinations". *Astronomy & Astrophysics* 391: 1115–1122. https://doi.org/10.1051/0004-6361:20020810 [^carruba2013a]: Carruba, V.; Huaman, M.; Domingos, R. C.; Roig, F. (2013). "Chaotic diffusion caused by close encounters with several massive asteroids. II. The regions of (10) Hygiea, (2) Pallas, and (31) Euphrosyne". *Astronomy & Astrophysics* 550: A85. https://doi.org/10.1051/0004-6361/201220448 [^carruba2013b]: Carruba, V. (2013). "An analysis of the Hygiea asteroid family orbital region". *Monthly Notices of the Royal Astronomical Society* 431: 3557–3569. https://doi.org/10.1093/mnras/stt437 [^depra2020]: De Prá, M. N.; Pinilla-Alonso, N.; Carvano, J.; et al. (2020). "A comparative analysis of the outer-belt primitive families". *Astronomy & Astrophysics* 643: A102. https://doi.org/10.1051/0004-6361/202038536 [^ferrais2021]: Ferrais, M.; Jehin, E.; Vernazza, P.; et al. (2021). "Lightcurve based determination of 10 Hygiea's rotational period with TRAPPIST-North and -South". *The Minor Planet Bulletin* 48: 166–167. Bibcode 2021MPBu...48..166F. [^groeneveld1954]: Groeneveld, I.; Kuiper, G. P. (1954). "Photometric studies of asteroids. II". *The Astrophysical Journal* 120: 529. https://doi.org/10.1086/145941 [^michalowski1991]: Michałowski, T.; Velichko, F. P.; Lindgren, M.; et al. (1991). "The spin vector of asteroid 10 Hygiea". *Astronomy & Astrophysics Supplement Series* 91: 53–59. Bibcode 1991A&AS...91...53M. [^rivkin2011]: Rivkin, A. S.; Milliken, R. E.; Emery, J. P.; Takir, D.; Schmidt, B. E. (2011). "2 Pallas and 10 Hygiea in the 3-µm spectral region". *EPSC-DPS Joint Meeting 2011*, abstract 1271. https://meetingorganizer.copernicus.org/EPSC-DPS2011/EPSC-DPS2011-1271.pdf [^cunningham2021]: Cunningham, C. J. (2021). *Asteroids*. Reaktion Books, p. 3. ISBN 978-1-78914-359-1. [^openstax]: Ling, S. J.; Sanny, J.; Moebs, W. (2016). *University Physics Volume 1*, ch. 13 "Gravitation". OpenStax. https://open.umn.edu/opentextbooks/textbooks/university-physics-volume-1 [^morrison1974]: Morrison, D. (1974). "Radiometric diameters and albedos of 40 asteroids". *The Astrophysical Journal* 194: 203–212. https://doi.org/10.1086/153236 [^scholl1987]: Scholl, H.; Schmadel, L. D.; Röser, S. (1987). "The mass of the asteroid (10) Hygiea derived from observations of (829) Academia". *Astronomy & Astrophysics* 179: 311–316. Bibcode 1987A&A...179..311S. [^michalak2001]: Michalak, G. (2001). "Determination of asteroid masses. II. (6) Hebe, (10) Hygiea, (15) Eunomia, (52) Europa, (88) Thisbe, (444) Gyptis, (511) Davida and (704) Interamnia". *Astronomy & Astrophysics* 374: 703–711. https://doi.org/10.1051/0004-6361:20010731 [^goffin2014]: Goffin, E. (2014). "Astrometric asteroid masses: a simultaneous determination". *Astronomy & Astrophysics* 565: A56. https://doi.org/10.1051/0004-6361/201322766 [^barucci2002]: Barucci, M. A.; Dotto, E.; Brucato, J. R.; et al. (2002). "10 Hygiea: ISO infrared observations". *Icarus* 156: 202–210. https://doi.org/10.1006/icar.2001.6775 [^lim2005]: Lim, L. F.; McConnochie, T. H.; Bell, J. F.; Hayward, T. L. (2005). "Thermal infrared (8–13 µm) spectra of 29 asteroids: the Cornell Mid-Infrared Asteroid Spectroscopy (MIDAS) survey". *Icarus* 173: 385–408. https://doi.org/10.1016/j.icarus.2004.08.005 [^rivkin2014]: Rivkin, A. S.; Asphaug, E.; Bottke, W. F. (2014). "The case of the missing Ceres family". *Icarus* 243: 429–439. https://doi.org/10.1016/j.icarus.2014.08.007 [^lebofsky1985]: Lebofsky, L. A.; Sykes, M. V.; Nolt, I. G.; et al. (1985). "Submillimeter observations of the asteroid 10 Hygiea". *Icarus* 63: 192–200. https://doi.org/10.1016/0019-1035(85)90003-X [^johnston1989]: Johnston, K. J.; Lamphear, E. J.; Webster, W. J.; et al. (1989). "The microwave spectra of the asteroids Pallas, Vesta, and Hygiea". *The Astronomical Journal* 98: 335–340. https://doi.org/10.1086/115150 [^busarev2011]: Busarev, V. V. (2011). "Asteroids 10 Hygiea, 135 Hertha, and 196 Philomela: heterogeneity of the material from the reflectance spectra". *Solar System Research* 45: 43–52. https://doi.org/10.1134/S0038094610061036 [^rivkin2019]: Rivkin, A. S.; Howell, E. S.; Emery, J. P. (2019). "Infrared spectroscopy of large, low-albedo asteroids: are Ceres and Themis archetypes or outliers?". *Journal of Geophysical Research: Planets* 124: 1393–1409. https://doi.org/10.1029/2018JE005833 [^hanus2017]: Hanuš, J.; Viikinkoski, M.; Marchis, F.; et al. (2017). "Volumes and bulk densities of forty asteroids from ADAM shape modeling". *Astronomy & Astrophysics* 601: A114. https://doi.org/10.1051/0004-6361/201629956 [^odeh]: Odeh, M. "The brightest asteroids". Jordanian Astronomical Society. http://jas.org.jo/ast.html [^ford2017]: Ford, D. (29 June 2017). "Asteroid 10 Hygiea at opposition". In-The-Sky.org. https://in-the-sky.org/news.php?id=20170629_14_100 [^watanabe2018]: Watanabe, H. (9 September 2018). "The index of asteroidal occultation results, worldwide, ver. 2". http://hal-astro-lab.com/data/occult-e/occult-e.html [^storrs1999]: Storrs, A. D.; Wells, E. N.; Zellner, B. H.; Stern, A.; Durda, D. D.; et al. (1999). "Imaging observations of asteroids with HST". *Bulletin of the American Astronomical Society* 31: 1089. Bibcode 1999BAAS...31Q1089S. [^sykes2006]: Sykes, M. V. (2006). "PSI proposes a distant asteroid mission". *Planetary Science Institute Newsletter* 7: 1–2. https://www.psi.edu/sites/default/files/imported/news/newsletter/Summer06.pdf [^vernazza2014]: Vernazza, P.; Lamy, P. (2014). "Investigation of the interior of primordial asteroids and the origin of the Earth's water: the INSIDER space mission". *Asteroids, Comets, Meteors 2014*, Helsinki. http://www.helsinki.fi/acm2014/pdf-material/Day-5/Posters-4/VERNAZZA-ABD6.pdf [^ulivi2014]: Ulivi, P.; Harland, D. M. (2014). *Robotic Exploration of the Solar System, Part 4: The Modern Era 2004–2013*. Springer, p. 431. ISBN 978-1-4614-4812-9. ## External links - ESO. "ESO telescope reveals what could be the smallest dwarf planet yet in the Solar System". https://www.eso.org/public/news/eso1918/ - JPL Small-Body Database. "10 Hygiea". https://ssd.jpl.nasa.gov/tools/sbdb_lookup.html#/?sstr=10 - NASA Science. "Asteroids". https://science.nasa.gov/solar-system/asteroids/ ## Wikipedia : Wikitube **Strict pair:** [Wikipedia](https://en.wikipedia.org/wiki/10_Hygiea) : [Wikitube](https://en.wikitube.io/wiki/10_Hygiea) · pinned revision [1373231571](https://en.wikipedia.org/w/index.php?oldid=1373231571) · 2026-09-18 ## Previous hub tags Hubs: `Life_Physics`. Portals: [[PORTAL_Solar_System]]. --- *Solar System portal child articles, wave 1 · 2026-09-18 · drafted · row SOL-051 · explorer state `?obj=Hygiea`.* <!-- hub_tags: Life_Physics · PORTAL_Solar_System -->