| Discovery[1] | |
|---|---|
| Discovered by | E. F. Helin |
| Discovery site | Palomar Obs. |
| Discovery date | 8 May 1991 |
| Designations | |
| (8026) Johnmckay | |
Named after | John B. McKay(test pilot)[2] |
| 1991 JA1 · 1989 UF2 | |
| main-belt · (inner)[1] Hungaria[2][3] | |
| Orbital characteristics[1] | |
| Epoch 4 September 2017 (JD 2458000.5) | |
| Uncertainty parameter 0 | |
| Observation arc | 27.33 yr (9,981 days) |
| Aphelion | 2.0697AU |
| Perihelion | 1.7809 AU |
| 1.9253 AU | |
| Eccentricity | 0.0750 |
| 2.67yr (976 days) | |
| 181.46° | |
| 0° 22m 8.04s / day | |
| Inclination | 19.936° |
| 217.71° | |
| 145.66° | |
| Knownsatellites | 1[4] |
| Physical characteristics | |
| Dimensions | 1.690±0.239 km[5][6] 2.54 km(calculated)[3] |
| 355±5 h[7] 372±5h[8] | |
| 0.30(assumed)[3] 0.815±0.196[5][6] | |
| E[3] | |
| 14.60±0.44[9] · 14.7[5] · 14.9[1][3] | |
8026 Johnmckay, provisional designation1991 JA1, is abinary[4] Hungariaasteroid and veryslow rotator from the inner regions of theasteroid belt, approximately 2 kilometers in diameter. It was discovered on 8 May 1991, by American astronomerEleanor Helin at the U.S.Palomar Observatory, California, and later named for NASA test pilotJohn B. McKay.[2]
The brightE-type asteroid is a member of theHungaria family, which form the innermost dense concentration of asteroids in the Solar System.Johnmckay orbits the Sun in theinner main-belt at a distance of 1.8–2.1 AU once every 2 years and 8 months (976 days). Its orbit has aneccentricity of 0.08 and aninclination of 20° with respect to theecliptic.[1] The first observation was made at the discovering observatory in 1989, extending the asteroid'sobservation arc by almost 2 years prior to its discovery.[2]
According to the survey carried out by theNEOWISE mission of NASA'sWide-field Infrared Survey Explorer,Johnmckay measures 1.7 kilometers in diameter and its surface has an exceptionally highalbedo of 0.81, while theCollaborative Asteroid Lightcurve Link assumes a standard albedo for Hungaria asteroids of 0.30, and calculates a diameter of 2.5 kilometers, based on anabsolute magnitude of 14.9.[3][5][6]
Two rotationallightcurves ofJohnmckay were obtained for this asteroid from photometric observations by U.S. astronomerBrian D. Warner at the Palmer Divide Station (PDO), Colorado. In August 2010, the first lightcurve gave a longrotation period of372±5 hours with a brightness variation of 1.0 inmagnitude (U=3).[8] The second lightcurve from June 2015, gave a similar period of355±5 with an amplitude of 0.66 in magnitude (U=2).[7]
This makesJohnmckay one of theTop 100+ slowest rotators known to exist.
In 2010 a smallasteroid moon was discovered around this asteroid. It has anorbital period of2.300±0.001 hours,[4] while observations at the PDO gave it a period of 2.2981 and 14.93 hours, respectively.[3][7][8]
Thisminor planet was named in memory of NASA test pilotJohn B. McKay (1922–1975), one of the first pilots assigned to fly theNorth American X-15. He was also assigned to theX-1E and to theD-558-II. He died in 1975, from injuries he had sustained during a X-15 crash. In 2005, he received posthumous theastronaut badge for a reached peak-altitude of 89,900 metres (295,000 feet).[2] The approved naming citation was published by theMinor Planet Center on 7 February 2012 (M.P.C. 78269).[10]
