| Discovery[1] | |
|---|---|
| Discovered by | E. F. Helin |
| Discovery site | Palomar Obs. |
| Discovery date | 4 January 1984 |
| Designations | |
| (3800) Karayusuf | |
Named after | Alford Karayusuf[1] (discoverer's friend) |
| 1984 AB · 1975 XL4 | |
| Mars-crosser[1][2][3] | |
| Orbital characteristics[2] | |
| Epoch 23 March 2018 (JD 2458200.5) | |
| Uncertainty parameter 0 | |
| Observation arc | 42.47yr (15,513 d) |
| Aphelion | 1.6974AU |
| Perihelion | 1.4584 AU |
| 1.5779 AU | |
| Eccentricity | 0.0757 |
| 1.98 yr (724 d) | |
| 349.96° | |
| 0° 29m 50.28s / day | |
| Inclination | 14.847° |
| 95.451° | |
| 115.76° | |
| Physical characteristics | |
| 2.51±0.25 km[4] | |
| 2.2319±0.0001 h[5][a] | |
| 0.281[4] | |
| SMASS =S[2] · S[3][6] L(SDSS-MOC)[7][8][9] | |
| 14.81±0.94[9] 15.00[1][2][3][4][10][11] 15.40[6] | |
3800 Karayusuf, provisional designation1984 AB, is aMars-crossing asteroid and suspectedbinary system from inside theasteroid belt, approximately 2.5 kilometers (1.6 miles) in diameter. It was discovered on 4 January 1984, by American astronomerEleanor Helin at thePalomar Observatory in California.[1] TheS/L-type asteroid has a shortrotation period of 2.2 hours.[3] It was named after Syrian physicianAlford Karayusuf, a friend of the discoverer.[1]
Karayusuf is aMars-crossing asteroid, a dynamically unstable group between themain-belt and thenear-Earth populations, crossing the orbit ofMars at 1.66 AU. It orbits the Sun at a distance of 1.46–1.70 AU once every 2 years (724 days;semi-major axis of 1.58 AU). Its orbit has aneccentricity of 0.08 and aninclination of 15° with respect to theecliptic. On 11 June 1938,Karayusuf passed 0.0151 AU (2,260,000 km; 1,400,000 mi) from Mars.[2]
The body'sobservation arc begins with its first observations as1975 XL4 atCrimea–Nauchnij in December 1975, almost 12 years prior to its official discovery observation at Palomar.[1]
Thisminor planet was named after Syrian physicianAlford Karayusuf, a supporter of the Near-earth asteroid research projects atJPL and a leader of the World Space Foundation's program of Solar System exploration.[1] The official naming citation was published by theMinor Planet Center on 2 November 1990 (M.P.C. 17221).[12] The main-belt asteroid5255 Johnsophie, also discovered by Helin, was named after Alford Karayusuf's children, John and Sophie(also see the asteroid'scitation).
In theSMASS classification,Karayusuf is a common, stonyS-type asteroid.[2] The asteroid has also been characterized as anL-type asteroid by theSloan Digital Sky Survey andPan-STARRS' photometric survey.[7][8][9]
In March 2008, a rotationallightcurve ofKarayusuf was obtained fromphotometric observations byBrian Warner at hisPalmer Divide Observatory in Colorado. Lightcurve analysis gave a well-definedrotation period of2.2319±0.0001 hours with a rather small brightness amplitude of 0.15magnitude (U=3).[5][a] The body's rotation is close to the threshold-period of that of afast rotator, which would fly apart if they were not composed of a solid, monolithic structure.
Follow-up observations by Warner in 2010, 2014 and 2018 gave similar results.[13][14][b] The asteroid was also observed byBrian Skiff (2.225 h) andWilliam Ryan (2.23 h) in 2018.[c]
During Brian Warner's photometric observations, two possible mutual eclipsing/occultation events were observed, indicating thatKarayusuf is abinary asteroid with asatellite in its orbit. The data, however, was insufficient to calculate a rotation period.[5] In 2010 and in 2014, when observing conditions had a nearly identical phase angle, no evidence of an orbiting minor-planet moon was found.[13][14] The results of the 2018-observation have not yet been published.[b]
According to the survey carried out by theNEOWISE mission of NASA'sWide-field Infrared Survey Explorer,Karayusuf measures 2.51 kilometers in diameter and its surface has analbedo between 0.281,[4] while other NEOWISE observations gave a diameter of 1.624 kilometers with a not very plausible albedo of 0.657.[10][11] TheCollaborative Asteroid Lightcurve Link assumes a standard albedo for a stony asteroid of 0.20 and calculates a diameter of 2.97 kilometers based on anabsolute magnitude of 15.0.[3]
