Discovered by C. Jackson MPC designation 1319 Disa Discovered 19 March 1934 Orbits Sun Discovery site Union Observatory | Discovery date 19 March 1934 Minor planet category main-belt · (outer) Absolute magnitude 11.1 Discoverer Cyril Jackson Asteroid group Asteroid belt | |
Named after Disa (orchid – flowering plant) Alternative names 1934 FO · 1929 GE
1970 FM · A908 EA People also search for 1320 Impala, 1318 Nerina, 1468 Zomba | ||
1319 Disa, provisional designation 1934 FO, is a carbonaceous asteroid from the outer region of the asteroid belt, approximately 25 kilometers in diameter. It was discovered on 19 March 1934, by English-born, South African astronomer Cyril Jackson at Johannesburg Observatory in South Africa.
Disa orbits the Sun at a distance of 2.4–3.6 AU once every 5 years and 2 months (1,885 days). Its orbit has an eccentricity of 0.21 and an inclination of 3° with respect to the ecliptic. It was first identified as A908 EA at Heidelberg Observatory in 1908. The body's observation arc begins in 1929, when it was identified as 1929 GE at the discovering observatory, 6 years prior to its official discovery observation.
A rotational light-curve of Disa was obtained by American astronomer Brian D. Warner at his Palmer Divide Observatory in March 2006, and by French amateur astronomer Pierre Antonini in February 2011, respectively. Analysis of both light-curves gave a well-defined rotation period of 7.08 hours with a brightness variation of 0.26 and 0.27 magnitude (U=3/3). In September 2013, photometric observations in the R-band at the Palomar Transient Factory gave a concurring light-curve of 7.082 hours and an amplitude of 0.24 magnitude (U=2).
According to the surveys carried out by the Japanese Akari satellite, and the 2014-results by NASA's Wide-field Infrared Survey Explorer with its subsequent NEOWISE mission, Disa measures 24.00 and 25.65 kilometers in diameter, and its surface has an albedo of 0.116 and 0.097, respectively. The Collaborative Asteroid Lightcurve Link assumes a standard albedo for carbonaceous C-type asteroids of 0.057 and calculates a diameter of 40.33 kilometers using an absolute magnitude of 10.7. Preliminary results by NEOWISE also classified the body as a reddish P-type asteroid.
This minor planet was named after Disa, also known as "African weed-orchid", a large genus of more than a hundred tropical orchids, common in southern Africa. In 1955, this naming citation was first published by Paul Herget in The Names of the Minor Planets (H 120).