174567 Varda is a large trans-Neptunian object, discovered on 21 June 2003 by American astronomer Jeffrey A. Larsen using survey images taken with the 0.9-meter Spacewatch telescope at the Kitt Peak National Observatory. As a dynamically hot classical Kuiper belt object, Varda orbits within the Kuiper belt region. Stellar occultations in 2018 show that Varda is likely an oblate spheroid with a flattening of 0.07 and an area equivalent diameter of . Other triaxial ellipsoid shape models remain mathematically unconstrained. The total mass of the binary system is approximately with Varda contributing around 86 to 90% of it. Varda's bulk density estimates remain highly ambiguous. James Webb Space Telescope data shows a surface temperature of . Abundant frozen carbon dioxide dominates its surface.
Because of its large size, some astronomers including Michael E. Brown and Noemi Pinilla-Alonso have considered it a possible dwarf planet. However, it is hypothesized that trans-Neptunian objects in the size range of 400–1000 km, such as Varda, have probably never compressed into fully solid bodies, let alone fall into hydrostatic equilibrium, and so are unlikely to be dwarf planets, though the density calculations for Varda are highly ambiguous. It is not clear if Varda's density is high enough to compressed into a fully solid body.
Varda has one known moon named Ilmarë. The moon's diameter measures approximately . Varda and Ilmarë are likely mutually tidally locked. The binary system exhibits a very large mass ratio, comparable to that of Pluto and Charon.
Observation history Discovery
Varda was discovered on 21 June 2003 by American astronomer Jeffrey A. Larsen as part of a United States Naval Academy Trident Scholar project. The discovery used survey images taken with the 0.9-meter Spacewatch telescope at the Kitt Peak National Observatory.
Larsen's survey ran for 34 months and covered approximately 8,000 square degrees of the sky to detect slow-moving trans-Neptunian objects. At the time of its announcement, Varda was the only large object discovered through this specific program and was thought to be the tenth-largest known classical Kuiper belt object. The Minor Planet Center officially announced the discovery on 7 January 2006. Astronomers later identified the earliest known precovery images of Varda from photographs taken at the Siding Spring Observatory on 19 March 1980.
Further observations Following its initial tracking under the provisional designation , Varda was regularly observed to secure its orbital path. Subsequent tracking utilized observations from Siding Spring, the Palomar Observatory, and Near-Earth Asteroid Tracking datasets,. forming a total observation arc of 39 years.
Occultations
Stellar occultations by Varda occur when it passes in front of a star and blocks its light, helping astronomers find its exact size, shape, flattening, geometric albedo and other physical properties.
The first successful stellar occultation by Varda was observed across the United States on 10 September 2018, using data from multiple monitoring sites to map the object's shape and density. Data from this event was also used to test for a thin nitrogen atmosphere like Pluto, though the results remained inconclusive due to potential camera instrumentation issues. While multiple occultations were predicted between 2022 and 2025 across South America, East Asia, Africa, and the Arctic, two campaigns on 11 March 2023 and 10 June 2024 specifically tracked separate shadow chords for both Varda and Ilmarë using stars with apparent magnitudes of around 15, with further calculation updates extended through 2027, involving stars with magnitudes ranging between 16.6 and 17.0.
Nomenclature
Before receiving its official name, Varda was known by the provisional designation . The Minor Planet Center (MPC) assigned it the permanent minor planet number 174567 on 22 January 2008. The names for Varda and its moon were announced by the MPC on 16 January 2014. The object is named after Varda, the queen of the Valar in J. R. R. Tolkien's Middle-earth writings. According to International Astronomical Union (IAU) guidelines, the discoverer can propose a name to a committee that judges whether it is suitable. Within Tolkien's legendarium, Varda functions as an "angelic power" or creator deity subordinate to the supreme God Eru Ilúvatar, responsible for shaping the stars to illuminate the world. Its moon was named Ilmarë, after a chief of the Maiar and Varda's handmaiden.
Planetary symbols are no longer widely used in modern astronomy, so Varda never received an official symbol. Astrologer Zane Stein proposed a stylized star glyph for Varda (), though it remained unofficial.
Orbit and classification
Varda orbits the Sun once every 309.2 years at an average orbital distance of 45.7 AU. In its orbit, Varda comes as close as 39.3 AU from the Sun at perihelion and as far as 52.1 AU from the Sun at aphelion. Its orbit has an eccentricity of approximately 0.14 and an inclination of 21.5° with respect to the ecliptic. , Varda is 47.5 AU from the Sun. It will come to perihelion around 28 July 2096.
Varda is located in the classical region of the Kuiper belt 39–48 AU from the Sun, and is thus classified as a typical member of a classical Kuiper belt object (also known as a "cubewano"). This classical population is most concentrated in a range between 42 and 47 AU. The high orbital inclination of Varda makes it a dynamically "hot" member of the classical Kuiper belt, separating it from the flat "cold" classical objects that have tilts under 5°. The hot classical Kuiper belt objects are believed to have been scattered by Neptune's gravitational influence into their dynamically excited paths during the Solar System's early history. Because its orbit is stable on long timescales, Varda is dynamically distinct from both the unstable scattered disk and the distant detached object families. However, a 2025 study found that Varda could be in a 15:8 resonance with Neptune. This means that for every 15 orbits Neptune completes around the Sun, Varda completes exactly 8.
Orbital stability Multiple simulations across large trans-Neptunian objects have found that Varda's orbit is very stable. In tests tracking the outer planets over one billion years, Varda stayed on its orbital path, it is predicted that it will never be ejected from the Solar System or pushed inward. Its estimated stability time is approximately 22.1 billion years, which is longer than the remaining life of the Solar System.
Physical characteristics Size
+ History of diameter estimates for Varda Year of Publication Diameter (km) Method References 2014 Thermal (Herschel system) 2014 Thermal (NEATM) 2015 Thermal (primary best estimate) 2019 Stellar Occultation 2020 Stellar Occultation 2020 Stellar Occultation 2026 Occultation reanalysis Varda has an area equivalent diameter of approximately . For comparison, this is about one-third Pluto's diameter. A multi-chord stellar occultation provided these parameters. This event occurred on 10 September 2018. Astronomers observed the occultation from the United States. The occultation data suggests Varda is an oblate spheroid. Varda features an equatorial diameter of . The apparent projected oblateness equals . This circular silhouette derives from a 3.81 absolute magnitude. Varda is a very large trans-Neptunian object and is among the top 34 largest known TNOs.
In a 2026 occultation reanalysis, data suggests that Varda has a highly flattened, triaxial ellipsoid shape with body dimensions of 778 × 706 × 496 km, resulting in a volume equivalent diameter of 648 km, much smaller than other size estimates. Using a different formula would result in axes of 778 × 706 × 432 km. Varda's long axis is directed toward its moon, Ilmarë. The chance for this alignment to happen by accident is calculated to be 2%. However, the published data are not able to fully constrain its three-dimensional shape.
Varda is possibly massive enough to pull itself into a nearly spherical object under its own gravity, this is called collapsing into hydrostatic equilibrium, which is one of the requirements for becoming a dwarf planet, thus, some astronomers including Michael E. Brown and Noemi Pinilla-Alonso have considered it a possible dwarf planet. However, William M. Grundy hypothesized that trans-Neptunian objects in the size range of 400–1000 km, such as Varda, have probably never compressed into fully solid bodies, let alone differentiated or fall into hydrostatic equilibrium, and so are unlikely to be dwarf planets, though the density calculations for Varda are highly ambiguous. It is not clear if Varda's density is high enough to compressed into a fully solid body. Its low albedo is however consistent with a lack of the geological activity that is thought to be typical of larger dwarf planets.
Mass and density
The total mass of the binary system is precisely and accurately determined. The combined mass of the Varda system is , with Varda probably contributing around 86.2% and 90.1% of this total system mass. The mass of the Varda system is about 1.62 percent that of , the most massive known dwarf planet ().
However, independent bulk density estimates of Varda remain highly ambiguous. These calculated densities depend entirely on assumed shape models. While the 2020 occultation models suggested under a single-peaked 5.91-hour rotation, alternative double-period models of 11.82 hours yielded a lower . A subsequent 2025 analysis derived a lower based on their estimated sizes, assuming if Varda and Ilmarë have the same densities. A 2026 study instead found a density of for Varda's triaxial shape model, which could possibly increase up to under other Jacobi ellipsoid formulas. Unfortunately, these recent 2026 estimates lack formal mathematical uncertainties. The nearly pole-on viewing geometry limits vertical constraints, leaving Varda's short c-axis unmeasured along our line of sight.
Surface Composition and spectrum
Varda shares its composition with the -type (aka "double-dip") trans-Neptunian objects, which are most commonly found on dynamically excited orbits such as those in the hot classical Kuiper belt, this is where Varda resides. This specific group features very large carbon dioxide abundances. Varda's independent carbon dioxide ice shows a 2.7 μm wavelength signal. Its measured carbon dioxide absorption area equals 0.00548 μm. Typically, double-dip spectra center a main absorption wavelength at 4.27 μm. Another statistical feature for this group appears at 4.06 μm. A rarer carbon dioxide type shows near the 4.38 μm wavelength. The standard group ice matrix traps volatile carbon monoxide gas. Furthermore, Varda completely lacks frozen methane and ammonia.
Varda has very little methanol ice on its surface. The methanol ice signal at 2.27 μm is small. Varda's precise methanol band area measures just 0.00008 μm. Earth telescopes in 2008 suggested methanol was present. However, those older ground signals were too weak. Newer space data shows these signals come from organics. Varda's surface has almost no water ice. Its water ice band index is only at −0.00072 μm. The telescope data lacks typical water ice shapes. Instead, complex organic materials show up near 3.4 μm. The measured aliphatic carbon-hydrogen band area equals 0.01021 μm. Small signals near 4.93 μm suggest group trace olivine rock.
Color, albedo and brightness
In visible light, Varda appears moderately red. Its measured color index values are B−V= and V–R=. This places Varda within the IR spectral class, for comparison, this B-V color index is similar to that of the dwarf planet Makemake's. Near-infrared spectral features serve as markers of surface complex organic compounds.