 Radar images of Midas by theArecibo Observatory in March 2018 | |
| Discovery[1] | |
|---|---|
| Discovered by | C. Kowal |
| Discovery site | Palomar Obs. |
| Discovery date | 6 March 1973 |
| Designations | |
| (1981) Midas | |
| Pronunciation | /ˈmaɪdəs/[2] |
Named after | Midās(Greek mythology)[3] |
| 1973 EA | |
| Orbital characteristics[1] | |
| Epoch 4 September 2017 (JD 2458000.5) | |
| Uncertainty parameter 0 | |
| Observation arc | 41.97 yr (15,330 days) |
| Aphelion | 2.9307 AU |
| Perihelion | 0.6212 AU |
| 1.7759 AU | |
| Eccentricity | 0.6502 |
| 2.37 yr (864 days) | |
| 256.48° | |
| 0° 24m 59.4s / day | |
| Inclination | 39.833° |
| 356.90° | |
| 267.80° | |
| Earth MOID | 0.0045 AU (1.8 LD) |
| Physical characteristics | |
| Dimensions | |
| 5.22 h[7][8] | |
1981 Midas, provisional designation1973 EA, is a vestoidasteroid, classified as anear-Earth object andpotentially hazardous asteroid, approximately 2 kilometers in diameter.[1]
It was discovered on 6 March 1973 by American astronomerCharles Kowal atPalomar Observatory in San Diego County, California.[4] It was named after KingMidas from Greek mythology.[3]
The moderately brightV-type asteroid is also anApollo asteroid, as well as aVenus andMars-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 aneccentricity of 0.65 and aninclination of 40° with respect to theecliptic.[1]
Midas has a lowminimum orbit intersection distance with Earth of 0.0036 AU (540,000 km; 330,000 mi), 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 0.0298 AU (4,460,000 km; 2,770,000 mi) from Earth.[12] The last notable close approach was on 21 March 2018 passing 0.08957 AU (13,399,000 km; 8,326,000 mi) from Earth[12] and shining at anapparent magnitude of +12.4.[13] The next notable close approach will be on 14 September 2032 passing slightly closer at 0.08635 AU (12,918,000 km; 8,027,000 mi) from Earth.[12] As noprecoveries are known, the asteroid'sobservation arc begins with its discovery observation at Palomar in 1973.[4]
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.[a] For comparisonEarth orbits the Sun at 30 km/s.
Three rotationallightcurves obtained from photometric observations gave a concurringrotation period of 5.24 hours with a relatively high brightness variation of 0.65, 0.8 and 0.87 inmagnitude, respectively (U=3/2/3).[8][7][9]
According to the survey carried out by the JapaneseAkari satellite,Midas measures 1.95 kilometers in diameter and its surface has analbedo of 0.293,[5] while theCollaborative Asteroid Lightcurve Link assumes an albedo of 0.266 and calculates an identical diameter of 1.95 kilometers with anabsolute magnitude of 15.6.[6]
In 1987,Midas was also detected by radar fromGoldstone Deep Space Communications Complex at a distance of 0.08 AU with a measured maximalradar cross-section of 0.1 km2.[14]
Thisminor planet was named after the figure from Greek mythology,Midas, the King ofPhrygia, 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 riverPactolus, other accounts also tell his death caused by starvation.[3] The officialnaming citation was published by theMinor Planet Center on 15 October 1977 (M.P.C. 4237).[15]
