3102 Krok, provisional designation , is a rare-type

asteroid An asteroid is a minor planet of the inner Solar System. Sizes and shapes of asteroids vary significantly, ranging from 1-meter rocks to a dwarf planet almost 1000 km in diameter; they are rocky, metallic or icy bodies with no atmosphere. ...

and slow rotator, classified as a

near-Earth object A near-Earth object (NEO) is any small Solar System body whose orbit brings it into proximity with Earth. By convention, a Solar System body is a NEO if its closest approach to the Sun (perihelion) is less than 1.3 astronomical units (AU). ...

of the

Amor group Amor Group was Scotland's largest independent business technology company before being acquired by Lockheed Martin in September 2013. The business was formed after a £28 million management buyout of Glasgow based Real Time Engineering Ltd. an ...

, that measures approximately 1.5 kilometers in diameter. It was discovered on 21 August 1981, by Slovak astronomer Ladislav Brožek at

Kleť Observatory Kleť Observatory ( cz, Hvězdárna Kleť; obs. code: 046) is an astronomical observatory in the Czech Republic. It is situated in South Bohemia, south of the summit of Mount Kleť, near the town of České Budějovice. Constructed in 1957, t ...

in the Czech Republic. The asteroid was named after

Duke Krok Duke Krok is a legendary figure in Czech history, being the first judge, or duke, of the Czech people. He was also the father of Princess Libuše and her sisters Kazi and Teta. The Cosmas Chronicle Perhaps the earliest mention of the Duke (as ...

a legendary Czech figure.

Classification and orbit

''Krok'' orbits the Sun at a distance of 1.2–3.1 AU once every 3 years and 2 months (1,152 days). Its orbit has an

eccentricity Eccentricity or eccentric may refer to: * Eccentricity (behavior), odd behavior on the part of a person, as opposed to being "normal" Mathematics, science and technology Mathematics * Off-center, in geometry * Eccentricity (graph theory) of a v ...

of 0.45 and an

inclination Orbital inclination measures the tilt of an object's orbit around a celestial body. It is expressed as the angle between a Plane of reference, reference plane and the orbital plane or Axis of rotation, axis of direction of the orbiting object ...

of 8 ° with respect to the

ecliptic The ecliptic or ecliptic plane is the orbital plane of the Earth around the Sun. From the perspective of an observer on Earth, the Sun's movement around the celestial sphere over the course of a year traces out a path along the ecliptic again ...

. The body's

observation arc In observational astronomy, the observation arc (or arc length) of a Solar System body is the time period between its earliest and latest observations, used for tracing the body's path. It is usually given in days or years. The term is mostly use ...

begins with its official discovery observation at Klet, as no

precoveries In astronomy, precovery (short for pre-discovery recovery) is the process of finding the image of an object in images or photographic plates predating its discovery, typically for the purpose of calculating a more accurate orbit. This happens mos ...

were taken and no prior identifications were made. It has an ''Earth

minimum orbital intersection distance Minimum orbit intersection distance (MOID) is a measure used in astronomy to assess potential close approaches and collision risks between astronomical objects. It is defined as the distance between the closest points of the osculating orbits of ...

'' of , which translates into 71.7 lunar distances.

Physical characteristics

In the

Tholen 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 differentiated ...

, ''Krok'' is characterized as a rare QRS-type. In the SMASS taxonomy it is classified as a common

S-type asteroid S-type asteroids are asteroids with a spectral type that is indicative of a siliceous (i.e. stony) mineralogical composition, hence the name. They have relatively high density. Approximately 17% of asteroids are of this type, making it the second ...

, and the "ExploreNEOs" Warm Spitzer program assigns a transitional Sqw-type. The R- and Q-types also belong to the larger group of stony asteroids.

Rotation and shape

In September 1991, a first rotational

lightcurve In astronomy, a light curve is a graph of light intensity of a celestial object or region as a function of time, typically with the magnitude of light received on the y axis and with time on the x axis. The light is usually in a particular frequ ...

of ''Krok'' was obtained by American astronomer Alan Harris. Lightcurve analysis gave an exceptionally long

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 147.8 hours with a brightness amplitude of 1.0

magnitude Magnitude may refer to: Mathematics *Euclidean vector, a quantity defined by both its magnitude and its direction *Magnitude (mathematics), the relative size of an object *Norm (mathematics), a term for the size or length of a vector *Order of ...

, which indicates that the body has a non-spheroidal shape (). Between 2000 and 2005, several photometric observations made by Czech astronomer

Petr Pravec Petr Pravec (born September 17, 1967) is a Czech astronomer and a discoverer of minor planets, born in Třinec, Czech Republic. Pravec is a prolific discoverer of binary asteroids, expert in photometric observations and rotational lightcurves a ...

gave a similar period between 149.4 and 151.8 and an amplitude of 0.7 to 1.3 (). This makes ''Krok'' as slow rotator.

Diameter and albedo

According to

Tom Gehrels Anton M.J. "Tom" Gehrels (February 21, 1925 – July 11, 2011) was a Dutch–American astronomer, Professor of Planetary Sciences, and Astronomer at the University of Arizona, Tucson. Biography Youth and education Gehrels was born at Haa ...

1994 publication "Hazards due to Comets and Asteroids", ''Krok'' measures 1.6 kilometers in diameter based on a generic surface

albedo Albedo (; ) is the measure of the diffuse reflection of sunlight, solar radiation out of the total solar radiation and measured on a scale from 0, corresponding to a black body that absorbs all incident radiation, to 1, corresponding to a body ...

of 0.15, while the ''Collaborative Asteroid Lightcurve Link'' assumes a standard albedo for stony

s of 0.20 and calculates a diameter of 1.48 kilometers with an

absolute magnitude Absolute magnitude () is a measure of the luminosity of a celestial object on an inverse Logarithmic scale, logarithmic Magnitude (astronomy), astronomical magnitude scale. An object's absolute magnitude is defined to be equal to the apparent mag ...

of 16.5.

Naming

This

minor planet According to the International Astronomical Union (IAU), a minor planet is an astronomical object in direct orbit around the Sun that is exclusively classified as neither a planet nor a comet. Before 2006, the IAU officially used the term ''minor ...

was named after

, a legendary figure in Czech history, and the first judge ("duke") of the Slavonic tribes in ancient Bohemia. He was also the father of Princess Libuše, who, together with her husband Přemysl founded the

Přemyslid dynasty The Přemyslid dynasty or House of Přemyslid ( cs, Přemyslovci, german: Premysliden, pl, Przemyślidzi) was a Bohemian royal dynasty that reigned in the Duchy of Bohemia and later Kingdom of Bohemia and Margraviate of Moravia (9th century–130 ...

of Czech royalty. The official naming citation was published on 18 December 1994 ().

References

External links

Asteroid Lightcurve Database (LCDB)
query form

)
Dictionary of Minor Planet Names
Google books

– Observatoire de Genève, Raoul Behrend * * * {{DEFAULTSORT:Krok 003102 Discoveries by Ladislav Brožek Named minor planets 003102 003102 19810821