Definition
3581 Alvarez is a numbered minor planet—specifically, a main‑belt asteroid—located between the orbits of Mars and Jupiter.
Overview
The object was discovered on 15 September 1985 by American astronomer Edward L. Bowell at the Anderson Mesa Station of the Lowell Observatory in Flagstaff, Arizona, United States. It received the provisional designation 1985 RC before being assigned its permanent number, 3581, by the Minor Planet Center. The asteroid resides in the inner region of the main asteroid belt and follows an orbit that lies entirely within the belt’s boundaries.
Etymology / Origin
The asteroid’s name honors Luis Walter Alvarez (1911 – 1988), an American physicist and Nobel laureate recognized for his work on the hydrogen bubble chamber and for contributions to particle physics. In addition, Alvarez, together with his son Walter Alvarez, proposed the extraterrestrial impact hypothesis for the Cretaceous–Paleogene (K–Pg) extinction event; the naming acknowledges both his scientific achievements and his influence on planetary science.
Characteristics
| Property | Approximate Value | Notes |
|---|---|---|
| Spectral type | S‑type (stony) | Determined from photometric and spectroscopic surveys of main‑belt asteroids. |
| Diameter | ~12 km | Derived from infrared surveys (e.g., NEOWISE); precise size may vary with assumed albedo. |
| Geometric albedo | ~0.20 | Typical for S‑type asteroids; specific measurement not confirmed. |
| Semimajor axis | ~2.30 AU | Places the asteroid in the inner main belt. |
| Eccentricity | ~0.12 | Indicates a modestly elliptical orbit. |
| Orbital inclination | ~6° to the ecliptic | Shows a slight tilt relative to the plane of the Solar System. |
| Orbital period | ~3.4 years (≈1 240 days) | Calculated from the semimajor axis using Kepler’s third law. |
| Rotation period | Not firmly established | Photometric observations have not yielded a definitive spin rate. |
Accurate information is not confirmed for several of the above parameters (e.g., exact diameter, albedo, rotation period), as published data vary among surveys and may be subject to revision.
Related Topics
- Main‑belt asteroids – The population of rocky bodies orbiting the Sun between Mars and Jupiter.
- Luis W. Alvarez – Nobel‑winning physicist noted for contributions to particle physics and the Alvarez impact hypothesis.
- Alvarez hypothesis – The proposal that a large extraterrestrial impact caused the mass extinction at the end of the Cretaceous period.
- Minor Planet Center – The organization responsible for the designation and cataloguing of small Solar System bodies.
- NASA’s Near‑Earth Object Program – While 3581 Alvarez is not a near‑Earth object, the program monitors and studies similar small bodies.