9994 Grotius , provisional designation , is a stony Rafita

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. ...

from the middle regions of the

asteroid belt The asteroid belt is a torus-shaped region in the Solar System, located roughly between the orbits of the planets Jupiter and Mars. It contains a great many solid, irregularly shaped bodies, of many sizes, but much smaller than planets, called ...

, approximately 3.5 kilometers in diameter. It was discovered during the

Palomar–Leiden survey The Palomar–Leiden survey (PLS) was a successful astronomical survey to study faint minor planets in a collaboration between the U.S Palomar Observatory and the Dutch Leiden Observatory, and resulted in the discovery of thousands of asteroids, ...

in 1960, and named after Dutch jurist

Hugo Grotius Hugo Grotius (; 10 April 1583 – 28 August 1645), also known as Huig de Groot () and Hugo de Groot (), was a Dutch humanist, diplomat, lawyer, theologian, jurist, poet and playwright. A teenage intellectual prodigy, he was born in Delft ...

Discovery

''Grotius'' was discovered on 24 September 1960, by the Dutch astronomers

Ingrid Ingrid may refer to: * Ingrid (given name) * Ingrid (record label), and artist collective * Ingrid Burley, rapper known mononymously as Ingrid * Tropical Storm Ingrid, various cyclones * 1026 Ingrid, an asteroid * InGrid, the grid computing project ...

and

Cornelis van Houten Cornelis Johannes van Houten (18 February 1920 – 24 August 2002) was a Dutch astronomer, sometimes referred to as Kees van Houten. Early life and education Born in The Hague, he spent his entire career at Leiden University except for a brief p ...

, on photographic plates taken by Dutch–American astronomer

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 ...

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, United States.

Survey designation

The

survey designation Provisional designation in astronomy is the naming convention applied to astronomical objects immediately following their discovery. The provisional designation is usually superseded by a permanent designation once a reliable orbit has been calcu ...

"P-L" stands for ''Palomar–Leiden'', named after Palomar Observatory and

Leiden Observatory Leiden Observatory ( nl, Sterrewacht Leiden) is an astronomical institute of Leiden University, in the Netherlands. Established in 1633 to house the quadrant of Rudolph Snellius, it is the oldest operating university observatory in the world, with ...

, which collaborated on the fruitful

in the 1960s. Gehrels used Palomar's

Samuel Oschin telescope The Samuel Oschin telescope, also called the Oschin Schmidt, is a Schmidt camera at the Palomar Observatory in northern San Diego County, California. It consists of a 49.75-inch Schmidt corrector plate and a 72-inch (f/2.5) mirror. The instrument ...

(also known as the 48-inch Schmidt Telescope), and shipped the

photographic plate Photographic plates preceded photographic film as a capture medium in photography, and were still used in some communities up until the late 20th century. The light-sensitive emulsion of silver salts was coated on a glass plate, typically thinn ...

s to Ingrid and Cornelis van Houten at Leiden Observatory where

astrometry Astrometry is a branch of astronomy that involves precise measurements of the positions and movements of stars and other celestial bodies. It provides the kinematics and physical origin of the Solar System and this galaxy, the Milky Way. His ...

was carried out. The trio are credited with the discovery of several thousand minor planets.

Orbit and classification

''Grotius'' orbits the Sun in the

central Central is an adjective usually referring to being in the center of some place or (mathematical) object. Central may also refer to: Directions and generalised locations * Central Africa, a region in the centre of Africa continent, also known as ...

main-belt at a distance of 2.1–3.0 AU once every 4 years and 2 months (1,518 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 0.18 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 7 ° 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 Palomar.

Rotation period

In August 2010, a 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 ''Grotius'' was obtained from photometric observations in the R-band at the

Palomar Transient Factory The Palomar Transient Factory (PTF, obs. code: I41), was an astronomical survey using a wide-field survey camera designed to search for optical transient and variable sources such as variable stars, supernovae, asteroids and comets. The projec ...

in California. Lightcurve analysis gave a

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 9.2189 hours with a brightness variation of 0.27

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 ...

().

Diameter and albedo

According to the survey carried out by the

NEOWISE Wide-field Infrared Survey Explorer (WISE, observatory code C51, Explorer 92 and SMEX-6) is a NASA infrared astronomy space telescope in the Explorers Program. It was launched in December 2009, and placed in hibernation mode in February 2011, ...

mission of NASA's

Wide-field Infrared Survey Explorer Wide-field Infrared Survey Explorer (WISE, observatory code C51, Explorer 92 and SMEX-6) is a NASA infrared astronomy space telescope in the Explorers Program. It was launched in December 2009, and placed in hibernation mode in February 2011, ...

, ''Grotius'' measures 3.746 kilometers in diameter and its surface has an

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 0.263. The ''Collaborative Asteroid Lightcurve Link'' assumes a standard albedo for stony asteroids of 0.20 and calculates a diameter of 3.38 kilometers based on 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 14.72.

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 for Dutch jurist

(1583–1645), who laid the foundations for

international law International law (also known as public international law and the law of nations) is the set of rules, norms, and standards generally recognized as binding between states. It establishes normative guidelines and a common conceptual framework for ...

, based on

natural law Natural law ( la, ius naturale, ''lex naturalis'') is a system of law based on a close observation of human nature, and based on values intrinsic to human nature that can be deduced and applied independently of positive law (the express enacte ...

. He was a

child prodigy A child prodigy is defined in psychology research literature as a person under the age of ten who produces meaningful output in some domain at the level of an adult expert. The term is also applied more broadly to young people who are extraor ...

and entered

Leiden University Leiden University (abbreviated as ''LEI''; nl, Universiteit Leiden) is a Public university, public research university in Leiden, Netherlands. The university was founded as a Protestant university in 1575 by William the Silent, William, Prince o ...

when he was just eleven years old. The approved 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 11 November 2000 ().

References

External links

Asteroid Lightcurve Database (LCDB)
query form

Dictionary of Minor Planet Names
Google books

– Observatoire de Genève, Raoul Behrend

– Minor Planet Center * * {{DEFAULTSORT:Grotius 009994 Discoveries by Cornelis Johannes van Houten Discoveries by Ingrid van Houten-Groeneveld Discoveries by Tom Gehrels 4028 Named minor planets 19600924