| Minorplanet: | yes |
| 1981 Midas | |
| Background: |
|
| Discovered: | 6 March 1973 |
| Mpc Name: | (1981) Midas |
| Alt Names: | 1973 EA |
| Pronounced: | [1] |
| Epoch: | 4 September 2017 (JD 2458000.5) |
| Uncertainty: | 0 |
| Observation Arc: | 41.97 yr (15,330 days) |
| Perihelion: | 0.6212 AU |
| Semimajor: | 1.7759 AU |
| Eccentricity: | 0.6502 |
| Period: | 2.37 yr (864 days) |
| Mean Motion: | / day |
| Inclination: | 39.833° |
| Asc Node: | 356.90° |
| Arg Peri: | 267.80° |
| Moid: | 0.0045 AU (1.8 LD) |
1981 Midas, provisional designation, is a vestoid asteroid, classified as a near-Earth object and potentially hazardous asteroid, approximately 2 kilometers in diameter.
It was discovered on 6 March 1973 by American astronomer Charles Kowal at Palomar Observatory in San Diego County, California. It was named after King Midas from Greek mythology.
The moderately bright V-type asteroid is also an Apollo asteroid, as well as a Venus and Mars-crosser. The asteroid orbits the Sun at a distance of 0.6–2.9 AU once every 2 years and 4 months (864 days). Its orbit has an eccentricity of 0.65 and an inclination of 40° with respect to the ecliptic.
Midas has a low minimum orbit intersection distance with Earth of 0.0036abbr=onNaNabbr=on, which corresponds to 1.5 lunar distance (Earth–Moon distance). However, it does not pose an impact risk for the foreseeable future. On 19 March 1947 it passed 0.0298abbr=onNaNabbr=on from Earth. The last notable close approach was on 21 March 2018 passing 0.08957abbr=onNaNabbr=on from Earth and shining at an apparent magnitude of +12.4. The next notable close approach will be on 14 September 2032 passing slightly closer at 0.08635abbr=onNaNabbr=on from Earth. As no precoveries are known, the asteroid's observation arc begins with its discovery observation at Palomar in 1973.
With a semi-major axis of 1.78 AU, when 1 AU from the Sun (and passing Earth's orbit) the asteroid is moving at 35.7 km/s with respect to the Sun. For comparison Earth orbits the Sun at 30 km/s.
Three rotational lightcurves obtained from photometric observations gave a concurring rotation period of 5.24 hours with a relatively high brightness variation of 0.65, 0.8 and 0.87 in magnitude, respectively .
According to the survey carried out by the Japanese Akari satellite, Midas measures 1.95 kilometers in diameter and its surface has an albedo of 0.293, while the Collaborative Asteroid Lightcurve Link assumes an albedo of 0.266 and calculates an identical diameter of 1.95 kilometers with an absolute magnitude of 15.6.
In 1987, Midas was also detected by radar from Goldstone Deep Space Communications Complex at a distance of 0.08 AU with a measured maximal radar cross-section of 0.1 km2.
This minor planet was named after the figure from Greek mythology, Midas, the King of Phrygia, who turned whatever he touched to gold. He received this ability as an award, but soon realized that this gift was a curse when his daughter turned into a statue after he had touched her. Relieved of his power by bathing in the river Pactolus, other accounts also tell his death caused by starvation. The official was published by the Minor Planet Center on 15 October 1977 .