Definition
1446 Sillanpää is a stony (S‑type) minor planet located in the inner region of the main asteroid belt between the orbits of Mars and Jupiter.
Overview
The asteroid was discovered on 18 January 1937 by Finnish astronomer Yrjö Väisälä at the Turku Observatory in Finland. It was later assigned the permanent number 1446 and received the name “Sillanpää” in honor of the Finnish author Frans Eemil Sillanpää, the 1939 Nobel Prize laureate in literature. The object follows an elliptical orbit around the Sun, residing in the inner main belt. Observations over several decades have yielded a well‑determined orbital solution and a modest rotational lightcurve.
Etymology / Origin
The name “Sillanpää” is derived from the surname of Frans Eemil Sillanpää (1888 – 1964), a Finnish novelist whose works contributed significantly to 20th‑century Finnish literature. The naming conforms to the International Astronomical Union’s practice of honoring notable cultural figures with asteroid designations.
Characteristics
- Spectral type: S‑type, indicating a silicate‑rich composition.
- Diameter: Estimates based on its absolute magnitude and assumed albedo place the diameter at roughly 10 km (± a few kilometres).
- Orbital parameters (approximate):
- Semi‑major axis: 2.2 – 2.5 AU
- Orbital period: about 3.8 years (≈ 1 388 days)
- Eccentricity: modest, typical of inner‑belt asteroids (≈ 0.1 – 0.2)
- Inclination: a few degrees relative to the ecliptic.
- Rotation: Photometric observations suggest a rotation period on the order of several hours, though precise values vary among published studies.
Related Topics
- Main‑belt asteroids – the population of rocky bodies orbiting between Mars and Jupiter.
- Minor‑planet naming conventions – the process governed by the International Astronomical Union for assigning names to numbered asteroids.
- Frans Eemil Sillanpää – Finnish author and Nobel laureate, after whom the asteroid is named.
- Yrjö Väisälä – Finnish astronomer notable for discovering numerous minor planets, including 1446 Sillanpää.