Discovery date 26 September 1960 Minor planet category main-belt · Themis Discovered 26 September 1960 Named after Hannes Alfvén (physicist) Discovery site Palomar Observatory | MPC designation 1778 Alfvén Observation arc 62.20 yr (22,719 days) Orbits Sun Asteroid family Themis family | |
Discovered by C. J. van Houten
I. van Houten-G.
Tom Gehrels Alternative names 4506 P-L · 1936 HK
1952 DD1 · 1958 FB
1959 NN Discoverers Tom Gehrels, Cornelis Johannes van Houten, Ingrid van Houten-Groeneveld Similar Solar System, 1996 Adams, Sun, 3047 Goethe | ||
1778 Alfvén, also designated 4506 P-L, is a carbonaceous Themistian asteroid from the outer region of the asteroid belt, approximately 20 kilometers in diameter. It was discovered on 26 September 1960, by astronomers Cornelis van Houten, Ingrid van Houten-Groeneveld and Tom Gehrels at the U.S. Palomar Observatory, in California.
The dark C-type asteroid is a member of the Themis family, a dynamical family of outer-belt asteroids with nearly coplanar ecliptical orbits. Alfvén orbits the Sun at a distance of 2.7–3.6 AU once every 5 years and 7 months (2,040 days). Its orbit has an eccentricity of 0.13 and an inclination of 2° with respect to the ecliptic. The first precovery was taken at Lowell Observatory in 1909. Its first used observation was also a precovery taken at Palomar Observatory in 1954, extending the body's observation arc by 6 years prior to its official discovery observation.
In February 2013, two rotational light-curves of Alfvén were obtained from analysis at the Palomar Transient Factory in California. The light-curves gave a rotation period of 4.82 and 4.8050 hours with a brightness variation of 0.40 and 0.36 magnitude, respectively (U=3-/2).
According to the survey carried out by NASA's Wide-field Infrared Survey Explorer with its subsequent NEOWISE mission, Alfvén measures 20.62 kilometers in diameter and its surface has an albedo of 0.095, while the Collaborative Asteroid Lightcurve Link assumes an albedo of 0.08 and calculates a diameter of 20.51 kilometers based on an absolute magnitude of 11.8.
The survey designation "P-L" stands for Palomar–Leiden, named after Palomar Observatory and Leiden Observatory, which collaborated on the fruitful Palomar–Leiden survey in the 1960s. Gehrels used Palomar's Samuel Oschin telescope (also known as the 48-inch Schmidt Telescope), and shipped the photographic plates to Ingrid and Cornelis van Houten at Leiden Observatory where astrometry was carried out. The trio are credited with the discovery of several thousand minor planets.
The asteroid was named after Swedish engineer, physicist and Nobel prize winner, Hannes Alfvén (1908–1995). Naming citation was published before November 1977 (M.P.C. 3643).