253921

253921 is a numbered minor planet in the main asteroid belt. The body received its official designation after its orbit was measured sufficiently to ensure a secure dynamics assessment. Like most numbered asteroids, the designation follows the sequential numbering system of the Minor Planet Center, reflecting the order in which its orbit was confirmed rather than any specific physical attribute.

The asteroid was first observed on 21 February 2005 by the Spacewatch survey operating at Kitt Peak National Observatory in Arizona. The discovery images were acquired in the R-band using a 0.9‑m telescope, and the object’s motion relative to background stars led to its initial provisional designation. Subsequent observations over several oppositions allowed the determination of a well‑constrained orbit.

Orbital elements place 253921 in the central region of the main belt, with a semimajor axis of approximately 2.48 astronomical units, an eccentricity of about 0.06, and an inclination of roughly 5.6 degrees to the ecliptic. The asteroid’s orbital period is around 3.92 Earth years. Photometric studies suggest an absolute magnitude near 14.9, which, when combined with an assumed albedo typical of C‑type asteroids, yields a diameter estimate of roughly 3.5 kilometers. Its spectral classification, while not yet confirmed, is consistent with a carbonaceous composition.

No official name has been assigned to this asteroid; it remains known solely by its provisional designation and numeric identifier. 253921 continues to be monitored by professional observatories to refine its orbital parameters and to observe its rotational light curve for insights into its shape and spin state.