3800 Karayusuf, provisional designation ', is a Mars-crossing asteroid and suspected binary system from inside the asteroid belt, approximately in diameter. It was discovered on 4 January 1984, by American astronomer Eleanor Helin at the

Palomar Observatory Palomar Observatory is an astronomical research observatory in San Diego County, California, United States, in the Palomar Mountain Range. It is owned and operated by the California Institute of Technology (Caltech). Research time at the observat ...

in California. The S/

L-type asteroid L-type asteroids are relatively uncommon asteroids with a strongly reddish spectrum shortwards of 0.75 μm, and a featureless flat spectrum longwards of this. In comparison with the K-type asteroid, K-type, they exhibit a more reddish spectrum at ...

has a short

rotation period The rotation period of a celestial object (e.g., star, gas giant, planet, moon, asteroid) may refer to its sidereal rotation period, i.e. the time that the object takes to complete a single revolution around its axis of rotation relative to the ...

of 2.2 hours. It was named after Syrian physician Alford Karayusuf, a friend of the discoverer.

Orbit and classification

''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 In geometry, the major axis of an ellipse is its longest diameter: a line segment that runs through the center and both foci, with ends at the two most widely separated points of the perimeter. The semi-major axis (major semiaxis) is the long ...

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 from Mars. The body's observation arc begins with its first observations as ' at Crimea–Nauchnij in December 1975, almost 12 years prior to its official discovery observation at Palomar.

Naming

This minor planet was named after Syrian physician Alford Karayusuf, a supporter of the Near-earth asteroid research projects at

JPL The Jet Propulsion Laboratory (JPL) is a federally funded research and development center and NASA field center in the City of La Cañada Flintridge, California, United States. Founded in the 1930s by Caltech researchers, JPL is owned by NASA an ...

and a leader of the World Space Foundation's program of Solar System exploration. The official naming citation was published by the

Minor Planet Center The Minor Planet Center (MPC) is the official body for observing and reporting on minor planets under the auspices of the International Astronomical Union (IAU). Founded in 1947, it operates at the Smithsonian Astrophysical Observatory. Function ...

on 2 November 1990 (). 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 )''.

Physical characteristics

In the

SMASS classification An asteroid spectral type is assigned to asteroids based on their emission spectrum, color, and sometimes albedo. These types are thought to correspond to an asteroid's surface composition. For small bodies that are not internally differentiat ...

, ''Karayusuf'' is a common, stony S-type asteroid. The asteroid has also been characterized as an

by the

Sloan Digital Sky Survey The Sloan Digital Sky Survey or SDSS is a major multi-spectral imaging and spectroscopic redshift survey using a dedicated 2.5-m wide-angle optical telescope at Apache Point Observatory in New Mexico, United States. The project began in 2000 a ...

and Pan-STARRS photometric survey.

Rotation period

In March 2008, a rotational lightcurve of ''Karayusuf'' was obtained from photometric observations by Brian Warner at his

Palmer Divide Observatory This is a list of observatory codes (IAU codes or MPC codes) published by the Minor Planet Center. For a detailed description, ''see observations of small Solar System bodies Observations of minor planets as well as comets and natural satellite ...

in Colorado. Lightcurve analysis gave a well-defined

of hours with a rather small brightness amplitude of 0.15 magnitude (). 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. The asteroid was also observed by Brian Skiff (2.225 h) and William Ryan (2.23 h) in 2018.

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. In 2010 and in 2014, when observing conditions had a nearly identical phase angle, no evidence of an orbiting minor-planet moon was found. The results of the 2018-observation have not yet been published.

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, while other NEOWISE observations gave a diameter of 1.624 kilometers with a not very plausible albedo of 0.657. 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.

Notes

References

External links

Asteroid Lightcurve Database (LCDB)
query form

)
Dictionary of Minor Planet Names
Google books

– Minor Planet Center * * {{DEFAULTSORT:Karayusuf 003800 Discoveries by Eleanor F. Helin Named minor planets 003800 19840104