# 625 Xenia
**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)
| Key fact | Detail |
|---|---|
| Designations | Minor planet (625) Xenia; provisional designation 1907 XN[1](https://asteroid.fandom.com/wiki/625_Xenia) |
| Discovery | 11 February 1907, Heidelberg, by August Kopff[1](https://asteroid.fandom.com/wiki/625_Xenia) • [3](https://clever-geek.imtqy.com/articles/1389671/) |
| 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) |
| Size and albedo | Diameter about 28.3 km; geometric albedo 0.221[2](https://www.spacereference.org/asteroid/625-xenia-a907-cg) |
| 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) |
| 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) |
| 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) |
## Discovery and naming
Xenia 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)
## Orbit
Xenia 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)
The 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)
## Physical characteristics
Xenia 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)
**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)
**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)
## Stellar occultations
When 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)
## Observation record
Xenia 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)
## References
1. [625 Xenia, Asteroid Wiki (Fandom)](https://asteroid.fandom.com/wiki/625_Xenia)
2. [Asteroid Xenia, Space Reference](https://www.spacereference.org/asteroid/625-xenia-a907-cg)
3. [Asteroid List (601–700)](https://clever-geek.imtqy.com/articles/1389671/)
4. [Planetka (625) Xenia, Planety.astro.cz](https://planety.astro.cz/planetka-625)
5. [CCD photometry of 625 Xenia, ResearchGate](https://www.researchgate.net/publication/346537920_CCD_photometry_of_625_Xenia)
6. [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)
7. [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)
8. [RASNZ Occultation Section: (625) Xenia occultation, 2007 May 25](https://occultations.org.nz/planet/2007/updates/070525_625_12156_u.htm)
9. [(625) Xenia hides a star, 2026 September 27, Occult](https://occult.alokm.com/asteroid?e=2026-09-27-625-xenia-547584)
10. [Small-Body Orbits & Ephemerides, JPL Solar System Dynamics](https://ssd.jpl.nasa.gov/sb/orbits.html)
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*Topic: Encyclopedia › Places and geography › Extraterrestrial places › Small bodies of the Solar System › Main-belt asteroids and numbered minor planets › Middle-belt asteroids*
*Initially written Oct 21, 2026*
*Copyright 2026 EdgeChat AI, a subsidiary of Biostate AI.*
License: Edgepedia Community License 1.0, https://www.edgepedia.org/edgepedia/license