(6645) Arcetri Main-belt Asteroid

Discovered on 11 January 1991 by E. F. Helin at Palomar.

Named for the Florence Observatory, moved in 1872 from the center of the city to Arcetri, near the house in which Galileo died. The original observatory, La Specola, was also associated with Galileo, and nineteenth-century directors included the comet hunters Pons, Donati and Tempel. It was Donati who moved the observatory to its present location.Naming citation (19961026/MPCPages.arc), IAU / Minor Planet Center, via NASA/JPL

Where Arcetri is today

Seen from above the solar system on 2026-10-14: Arcetri is 3.75 au from the Sun and 4.57 au from Earth. Computed from JPL's orbital elements.

Facts

Number	6645
Provisional designation	1991 AR1
Orbit class	Main-belt Asteroid
Diameter	11.9 km (#4,124 largest of 17,440 named asteroids with a measured size)
Albedo	0.125
Absolute magnitude (H)	13.03
Orbital period	5.54 years
Semi-major axis	3.13 au
Perihelion – aphelion	2.51 – 3.75 au
Eccentricity	0.199
Inclination	0.786°
Closest distance between its orbit and Earth's (MOID)	1.52 au

Data: NASA/JPL Small-Body Database and the IAU Minor Planet Center.

Also named after someone called Florence

All asteroids named after someone called Florence

Also discovered on 11 January 1991

(5624) Shirley

More named asteroids discovered by E. F. Helin

All 267

← (6644) Jugaku · (6646) Churanta →