{ "id": "epp1w9xszs", "slug": "625-xenia", "title": "625 Xenia", "updated": "2026-10-21", "topic_path": [ { "id": "places", "label": "Places and geography", "api_url": "https://www.edgepedia.org/api/v1/topics/places" }, { "id": "places.extraterrestrial", "label": "Extraterrestrial places", "api_url": "https://www.edgepedia.org/api/v1/topics/places.extraterrestrial" }, { "id": "places.extraterrestrial.small-bodies", "label": "Small bodies of the Solar System", "api_url": "https://www.edgepedia.org/api/v1/topics/places.extraterrestrial.small-bodies" }, { "id": "places.extraterrestrial.small-bodies.asteroids-main-belt", "label": "Main-belt asteroids and numbered minor planets", "api_url": "https://www.edgepedia.org/api/v1/topics/places.extraterrestrial.small-bodies.asteroids-main-belt" }, { "id": "places.extraterrestrial.small-bodies.asteroids-main-belt.middle-belt-asteroids", "label": "Middle-belt asteroids", "api_url": "https://www.edgepedia.org/api/v1/topics/places.extraterrestrial.small-bodies.asteroids-main-belt.middle-belt-asteroids" } ], "geo": [ { "id": "geo.nongeo.nodate.places.extraterrestrial.small-bodies.asteroids-main-belt.middle-belt-asteroids", "label": "Non-geographic · Not dated: Middle-belt asteroids", "api_url": "https://www.edgepedia.org/api/v1/geo/geo.nongeo.nodate.places.extraterrestrial.small-bodies.asteroids-main-belt.middle-belt-asteroids", "path": [ { "id": "geo.nongeo", "label": "Non-geographic", "api_url": "https://www.edgepedia.org/api/v1/geo/geo.nongeo" }, { "id": "geo.nongeo.nodate", "label": "Non-geographic · Not dated", "api_url": "https://www.edgepedia.org/api/v1/geo/geo.nongeo.nodate" }, { "id": "geo.nongeo.nodate.places", "label": "Places and geography", "api_url": "https://www.edgepedia.org/api/v1/geo/geo.nongeo.nodate.places" }, { "id": "geo.nongeo.nodate.places.extraterrestrial", "label": "Extraterrestrial places", "api_url": "https://www.edgepedia.org/api/v1/geo/geo.nongeo.nodate.places.extraterrestrial" }, { "id": "geo.nongeo.nodate.places.extraterrestrial.small-bodies", "label": "Small bodies of the Solar System", "api_url": "https://www.edgepedia.org/api/v1/geo/geo.nongeo.nodate.places.extraterrestrial.small-bodies" }, { "id": "geo.nongeo.nodate.places.extraterrestrial.small-bodies.asteroids-main-belt", "label": "Main-belt asteroids and numbered minor planets", "api_url": "https://www.edgepedia.org/api/v1/geo/geo.nongeo.nodate.places.extraterrestrial.small-bodies.asteroids-main-belt" }, { "id": "geo.nongeo.nodate.places.extraterrestrial.small-bodies.asteroids-main-belt.middle-belt-asteroids", "label": "Middle-belt asteroids", "api_url": "https://www.edgepedia.org/api/v1/geo/geo.nongeo.nodate.places.extraterrestrial.small-bodies.asteroids-main-belt.middle-belt-asteroids" } ] } ], "excerpt": "625 Xenia (1907 XN), a roughly 28 km S-type main-belt asteroid discovered by August Kopff at Heidelberg on 11 February 1907; 4.3-year orbit, 21.1-hour rotation, not hazardous.", "snippet": "625 Xenia (1907 XN), a roughly 28 km S-type main-belt asteroid discovered by August Kopff at Heidelberg on 11 February 1907; 4.3-year orbit, 21.1-hour rotation, not hazardous.", "node": "places.extraterrestrial.small-bodies.asteroids-main-belt.middle-belt-asteroids", "markdown": "# 625 Xenia\n\n**625 Xenia** is a main-belt asteroid, a rocky body orbiting the Sun between Mars and Jupiter, discovered by the German astronomer August Kopff at [Heidelberg](https://www.edgepedia.org/heidelberg) on 11 February 1907.[1](https://asteroid.fandom.com/wiki/625_Xenia) It received the provisional designation 1907 XN, and the final name may have been inspired by that designation.[1](https://asteroid.fandom.com/wiki/625_Xenia) With a diameter of about 28 km, it is a mid-sized member of the main belt, and its orbit keeps it far from Earth, so it is not classified as potentially hazardous.[2](https://www.spacereference.org/asteroid/625-xenia-a907-cg)\n\n| Key fact | Detail |\n|---|---|\n| Designations | Minor planet (625) Xenia; provisional designation 1907 XN[1](https://asteroid.fandom.com/wiki/625_Xenia) |\n| Discovery | 11 February 1907, Heidelberg, by August Kopff[1](https://asteroid.fandom.com/wiki/625_Xenia) • [3](https://clever-geek.imtqy.com/articles/1389671/) |\n| Orbit | Semi-major axis 2.6454 au, eccentricity 0.2271, inclination 12.0768°; period 4.303 years (1,571.5 days)[4](https://planety.astro.cz/planetka-625) |\n| Size and albedo | Diameter about 28.3 km; geometric albedo 0.221[2](https://www.spacereference.org/asteroid/625-xenia-a907-cg) |\n| Rotation | About 21.1 hours per rotation; lightcurve amplitude 0.50 ± 0.05 magnitude[5](https://www.researchgate.net/publication/346537920_CCD_photometry_of_625_Xenia) |\n| Spectral type | S in the Tholen system, Sw in the DeMeo system, Sa in the SMASS system[6](https://ri.conicet.gov.ar/bitstream/11336/63617/2/CONICET_Digital_Nro.8c5e7e2b-0de4-45a0-9a6e-86cd675330c9_A.pdf) • [2](https://www.spacereference.org/asteroid/625-xenia-a907-cg) |\n| Hazard status | Not a potentially hazardous asteroid; its orbit passes 1.04 au from Earth's orbit at the closest point[2](https://www.spacereference.org/asteroid/625-xenia-a907-cg) |\n\n## Discovery and naming\n\nXenia was found on 11 February 1907 at the Heidelberg observatory in Germany, one day after Kopff's discovery of 624 Hektor and on the same night as [626 Notburga](https://www.edgepedia.org/626-notburga).[1](https://asteroid.fandom.com/wiki/625_Xenia) • [3](https://clever-geek.imtqy.com/articles/1389671/) The provisional designation assigned at discovery was 1907 XN, following the early twentieth-century convention of letter codes; the name Xenia may have been chosen in reference to those letters.[1](https://asteroid.fandom.com/wiki/625_Xenia)\n\n## Orbit\n\nXenia orbits in the main portion of the asteroid belt. Its orbit has a semi-major axis of 2.6454 au, an eccentricity of 0.2271, and an inclination of 12.0768° to the ecliptic, carrying it from perihelion at 2.045 au to aphelion at 3.246 au over a period of 4.303 years, or 1,571.5 days.[4](https://planety.astro.cz/planetka-625) Its average orbital speed is 18.34 km/s, and its [Tisserand parameter](https://www.edgepedia.org/tisserand-parameter) with respect to Jupiter, a value used to distinguish asteroidal from cometary dynamics, is 3.3.[2](https://www.spacereference.org/asteroid/625-xenia-a907-cg) • [4](https://planety.astro.cz/planetka-625)\n\nThe orbit poses no hazard to Earth. At its closest point, Xenia's orbit lies 1.04 au from [Earth's orbit](https://www.edgepedia.org/earths-orbit), and orbital simulations by NASA JPL's Center for Near-Earth Object Studies show no close approaches; JPL has therefore not classified it as a potentially hazardous object, and it is not considered a viable target for human exploration by the NHATS study.[2](https://www.spacereference.org/asteroid/625-xenia-a907-cg) For the period through 2050, the closest computed approach to Earth is 1.04 au on 7 August 2042, when the asteroid is expected to reach magnitude 11.8, its brightest in that interval.[4](https://planety.astro.cz/planetka-625) Successive perihelion passages fall on 30 June 2025, 19 October 2029, and 6 February 2034.[4](https://planety.astro.cz/planetka-625)\n\n## Physical characteristics\n\nXenia is about 28.3 km in diameter, with a geometric albedo of 0.221, meaning it reflects roughly 22 percent of the sunlight striking its surface.[2](https://www.spacereference.org/asteroid/625-xenia-a907-cg) Its absolute magnitude, the brightness it would have at 1 au from both Sun and observer at zero phase angle, is 9.97.[4](https://planety.astro.cz/planetka-625)\n\n**Rotation and shape.** CCD photometry, precise brightness measurements with a digital camera, gave a rotation period of 21.101 ± 0.032 hours with a lightcurve amplitude of 0.50 ± 0.05 magnitude, indicating a moderately elongated body.[5](https://www.researchgate.net/publication/346537920_CCD_photometry_of_625_Xenia) A convex shape model derived by the lightcurve inversion method, which reconstructs a three-dimensional shape from brightness variations, uses a rotation period of 21.0122 hours.[7](https://research-repository.st-andrews.ac.uk/bitstream/handle/10023/8593/Scholz_2016_A_A_ConvexShapeModels_FinalPubVersion.pdf?sequence=1)\n\n**Composition.** Spectroscopically, Xenia belongs to the S-complex, the moderately bright, stony class that dominates the inner main belt: it is type S in the Tholen system and Sw in the DeMeo system in a polarimetric survey of main-belt asteroids.[6](https://ri.conicet.gov.ar/bitstream/11336/63617/2/CONICET_Digital_Nro.8c5e7e2b-0de4-45a0-9a6e-86cd675330c9_A.pdf) The SMASS classification lists it as Sa.[2](https://www.spacereference.org/asteroid/625-xenia-a907-cg)\n\n## Stellar occultations\n\nWhen Xenia passes in front of a star, observers along a narrow track can time the disappearance to measure the asteroid's size and shape directly. On 25 May 2007 it occulted an 11.5-magnitude star in the constellation [Virgo](https://www.edgepedia.org/virgo-constellation) for observers along a path across the South Island of New Zealand beginning just south of [Christchurch](https://www.edgepedia.org/christchurch) and moving west, with the asteroid's shadow traveling at 10.1571 km/s.[8](https://occultations.org.nz/planet/2007/updates/070525_625_12156_u.htm) A further occultation of a magnitude 10.0 star is predicted for 27 September 2026; at one reference location the chance of catching the event is under 1 percent, with a path uncertainty of 23 km at one standard deviation, and the asteroid at magnitude 15.7 and 3.1 au from Earth.[9](https://occult.alokm.com/asteroid?e=2026-09-27-625-xenia-547584)\n\n## Observation record\n\nXenia has one of the longer observation arcs among minor planets: it has been observed in every era from its 1907 discovery through 2026, across 48 oppositions, with 5,168 individual observations recorded as of 25 May 2026.[4](https://planety.astro.cz/planetka-625) The IAU Minor Planet Center lists 4,025 observations used in the orbit determination, and the orbit is maintained with current elements in JPL's Small-Body DataBase, which recomputes small-body orbits as new astrometry becomes available.[2](https://www.spacereference.org/asteroid/625-xenia-a907-cg) • [10](https://ssd.jpl.nasa.gov/sb/orbits.html) Objects with dynamically similar orbits include [15 Eunomia](https://www.edgepedia.org/15-eunomia), 26 [Proserpina](https://www.edgepedia.org/proserpina), and [37 Fides](https://www.edgepedia.org/37-fides).[2](https://www.spacereference.org/asteroid/625-xenia-a907-cg)\n\n## References\n\n1. [625 Xenia, Asteroid Wiki (Fandom)](https://asteroid.fandom.com/wiki/625_Xenia)\n2. [Asteroid Xenia, Space Reference](https://www.spacereference.org/asteroid/625-xenia-a907-cg)\n3. [Asteroid List (601–700)](https://clever-geek.imtqy.com/articles/1389671/)\n4. [Planetka (625) Xenia, Planety.astro.cz](https://planety.astro.cz/planetka-625)\n5. [CCD photometry of 625 Xenia, ResearchGate](https://www.researchgate.net/publication/346537920_CCD_photometry_of_625_Xenia)\n6. [Belskaya et al. (2017), Icarus 284, 30–42: polarimetric classification of main-belt asteroids](https://ri.conicet.gov.ar/bitstream/11336/63617/2/CONICET_Digital_Nro.8c5e7e2b-0de4-45a0-9a6e-86cd675330c9_A.pdf)\n7. [Hanuš et al. (2016), A&A 586, A108: new and updated convex shape models of asteroids](https://research-repository.st-andrews.ac.uk/bitstream/handle/10023/8593/Scholz_2016_A_A_ConvexShapeModels_FinalPubVersion.pdf?sequence=1)\n8. [RASNZ Occultation Section: (625) Xenia occultation, 2007 May 25](https://occultations.org.nz/planet/2007/updates/070525_625_12156_u.htm)\n9. [(625) Xenia hides a star, 2026 September 27, Occult](https://occult.alokm.com/asteroid?e=2026-09-27-625-xenia-547584)\n10. [Small-Body Orbits & Ephemerides, JPL Solar System Dynamics](https://ssd.jpl.nasa.gov/sb/orbits.html)\n\n---\n*Topic: Encyclopedia › Places and geography › Extraterrestrial places › Small bodies of the Solar System › Main-belt asteroids and numbered minor planets › Middle-belt asteroids*\n\n*Initially written Oct 21, 2026*\n\n*Copyright 2026 EdgeChat AI, a subsidiary of Biostate AI.*\n\nLicense: Edgepedia Community License 1.0, https://www.edgepedia.org/edgepedia/license\n", "same_as": [], "url": "https://www.edgepedia.org/625-xenia", "markdown_url": "https://www.edgepedia.org/625-xenia.md", "license": { "name": "Edgepedia Community License 1.0", "url": "https://www.edgepedia.org/edgepedia/license", "summary": "Free with credit, commercial use included. AI training is open to everyone. For other uses, organizations over USD 100M in revenue or 100M monthly users license separately.", "spdx": "LicenseRef-Edgepedia-Community-1.0" }, "credit": "\"625 Xenia\", Edgepedia (EdgeChat), https://www.edgepedia.org/625-xenia. Edgepedia Community License 1.0.", "credit_md": "\"[625 Xenia](https://www.edgepedia.org/625-xenia)\", Edgepedia (EdgeChat), [https://www.edgepedia.org/625-xenia](https://www.edgepedia.org/625-xenia). [Edgepedia Community License 1.0](https://www.edgepedia.org/edgepedia/license).", "credit_html": "\"625 Xenia\", Edgepedia (EdgeChat), https://www.edgepedia.org/625-xenia. Edgepedia Community License 1.0.", "speakable": "625 Xenia, a roughly 28 km S-type main-belt asteroid discovered by August Kopff at Heidelberg on 11 February 1907; 4.3-year orbit, 21.1-hour rotation, not hazardous." }