(4643) Cisneros Main-belt Asteroid

Discovered on 23 August 1990 by H. E. Holt at Palomar.

Named in honor of Ernest Cisneros (b. 1964), one of the unsung heroes of planetary science. Cisneros began his career as a field geologist but has turned his energies to computer system management, software development, networking and data processing. Throughout the flight portion of the NEAR mission, Ernest insured that key hardware and software elements were developed and implemented. During the flybys of (253) Mathilde and (433) Eros (as well as the Earth), Ernest worked with the science team delivering calibrated data within minutes of telemetry arrival for both optical navigation and science analysis. Name proposed by J. Veverka and citation written by M. Robinson.Naming citation (WGSBN Bull. 6, #1, 4), IAU / Minor Planet Center, via NASA/JPL

Where Cisneros is today

Seen from above the solar system on 2026-10-14: Cisneros is 1.90 au from the Sun and 1.82 au from Earth. Computed from JPL's orbital elements.

Facts

Number	4643
Provisional designation	1990 QD6
Orbit class	Main-belt Asteroid
Diameter	5.68 km (#9,434 largest of 17,440 named asteroids with a measured size)
Albedo	0.262
Rotation period	5.25 hours
Absolute magnitude (H)	13.61
Orbital period	3.63 years
Semi-major axis	2.36 au
Perihelion – aphelion	1.89 – 2.84 au
Eccentricity	0.201
Inclination	1.78°
Closest distance between its orbit and Earth's (MOID)	0.870 au

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

Also named after someone called Ernest

All asteroids named after someone called Ernest

Also discovered on 23 August 1990

More named asteroids discovered by H. E. Holt

All 119

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