3800 Karayusuf
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| 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 | 42.47 yr (15,513 d) |
| Aphelion | 1.6974 AU |
| 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 designation 1984 AB, is a Mars-crossing asteroid and suspected binary system from inside the asteroid belt, approximately 2.5 kilometers (1.6 miles) in diameter. It was discovered on 4 January 1984, by American astronomer Eleanor Helin at the Palomar Observatory in California.[1] The S/L-type asteroid has a short rotation period of 2.2 hours.[3] It was named after Syrian physician Alford Karayusuf, a friend of the discoverer.[1]
Karayusuf is a Mars-crossing asteroid, a dynamically unstable group between the main-belt and the near-Earth populations, crossing the orbit of Mars 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 an eccentricity of 0.08 and an inclination of 15° with respect to the ecliptic. On 11 June 1938, Karayusuf passed 0.0151 AU (2,260,000 km; 1,400,000 mi) from Mars.[2]
The body's observation arc begins with its first observations as 1975 XL4 at Crimea–Nauchnij in December 1975, almost 12 years prior to its official discovery observation at Palomar.[1]
Naming
This minor planet was named after Syrian physician Alford Karayusuf, a supporter of the Near-earth asteroid research projects at JPL and a leader of the World Space Foundation's program of Solar System exploration.[1] The official naming citation was published by the Minor Planet Center on 2 November 1990 (M.P.C. 17221).[12] The main-belt asteroid 5255 Johnsophie, also discovered by Helin, was named after Alford Karayusuf's children, John and Sophie (also see the asteroid's citation).
Physical characteristics
In the SMASS classification, Karayusuf is a common, stony S-type asteroid.[2] The asteroid has also been characterized as an L-type asteroid by the Sloan Digital Sky Survey and Pan-STARRS' photometric survey.[7][8][9]
Rotation period
In March 2008, a rotational lightcurve of Karayusuf was obtained from photometric observations by Brian Warner at his Palmer Divide Observatory in Colorado. Lightcurve analysis gave a well-defined rotation period of 2.2319±0.0001 hours with a rather small brightness amplitude of 0.15 magnitude (U=3).[5][a] The body's rotation is close to the threshold-period of that of a fast 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 by Brian Skiff (2.225 h) and William Ryan (2.23 h) in 2018.[c]
Binary candidate
During Brian Warner's photometric observations, two possible mutual eclipsing/occultation events were observed, indicating that Karayusuf is a binary asteroid with a satellite 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]
Diameter and albedo
According to the survey carried out by the NEOWISE mission of NASA's Wide-field Infrared Survey Explorer, Karayusuf measures 2.51 kilometers in diameter and its surface has an albedo 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] The Collaborative Asteroid Lightcurve Link assumes a standard albedo for a stony asteroid of 0.20 and calculates a diameter of 2.97 kilometers based on an absolute magnitude of 15.0.[3]
