2741 Valdivia ( ''prov. designation'': ) is a

background asteroid An asteroid family is a population of asteroids that share similar proper orbital elements, such as semimajor axis, eccentricity, and orbital inclination. The members of the families are thought to be fragments of past asteroid collisions. An ...

from the central regions of the

asteroid belt The asteroid belt is a torus-shaped region in the Solar System, centered on the Sun and roughly spanning the space between the orbits of the planets Jupiter and Mars. It contains a great many solid, irregularly shaped bodies called asteroids ...

, approximately in diameter. It was discovered on 1 December 1975, by Chilean astronomers Carlos Torres and Sergio Barros at the Cerro El Roble Station northwest of Santiago de Chile. The asteroid was named after Spanish conquistador

Pedro de Valdivia Pedro Gutiérrez de Valdivia or Valdiva (; April 17, 1497 – December 25, 1553) was a Spanish ''conquistador'' and the first royal governor of Chile. After having served with the Spanish army in Italy and Flanders, he was sent to South America in ...

Orbit and classification

''Valdivia'' is a non-

family Family (from ) is a Social group, group of people related either by consanguinity (by recognized birth) or Affinity (law), affinity (by marriage or other relationship). It forms the basis for social order. Ideally, families offer predictabili ...

asteroid from the main belt's background population. It orbits the Sun in the central main-belt at a distance of 2.1–3.1 AU once every 4 years and 3 months (1,540 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-Centre (geometry), center, in geometry * Eccentricity (g ...

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 reference plane and the orbital plane or axis of direction of the orbiting object. For a satellite orbiting the Eart ...

of 10 ° with respect to the

ecliptic The ecliptic or ecliptic plane is the orbital plane of Earth's orbit, Earth around the Sun. It was a central concept in a number of ancient sciences, providing the framework for key measurements in astronomy, astrology and calendar-making. Fr ...

. The asteroid was first observed as at

Uccle Observatory The Royal Observatory of Belgium (; ; ) has been situated in the Uccle municipality of Brussels since 1890. It is part of the institutions of the Belgian Federal Science Policy Office (BELSPO). The Royal Observatory was first established in Sa ...

in February 1935, where 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 just a two weeks later, or more than 40 years before its official discovery observation at Cerro El Roble.

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 Spanish conquistador

(1502–1553), who conquered Chile with a small expedition corps after he served under

Francisco Pizarro Francisco Pizarro, Marquess of the Atabillos (; ; – 26 June 1541) was a Spanish ''conquistador'', best known for his expeditions that led to the Spanish conquest of the Inca Empire. Born in Trujillo, Cáceres, Trujillo, Spain, to a poor fam ...

in Peru. Valdivia founded the cities

Santiago Santiago (, ; ), also known as Santiago de Chile (), is the capital and largest city of Chile and one of the largest cities in the Americas. It is located in the country's central valley and is the center of the Santiago Metropolitan Regi ...

(1541) and Concepción (1550) and became Chile's first royal governor. The city of

Valdivia Valdivia (; Mapuche: Ainil) is a city and commune in southern Chile, administered by the Municipality of Valdivia. The city is named after its founder, Pedro de Valdivia, and is located at the confluence of the Calle-Calle, Valdivia, and ...

in southern Chile is also named after him. 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. Funct ...

on 26 March 1986 ().

Physical characteristics

Rotation period

In August 2016, the so-far best-rated rotational

lightcurve In astronomy, a light curve is a graph (discrete mathematics), graph of the Radiance, light intensity of a celestial object or region as a function of time, typically with the magnitude (astronomy), magnitude of light received on the ''y''-axis ...

of ''Valdivia'' was obtained by the Spanish amateur astronomer group OBAS. Lightcurve analysis gave a

rotation period In astronomy, the rotation period or spin period of a celestial object (e.g., star, planet, moon, asteroid) has two definitions. The first one corresponds to the '' sidereal rotation period'' (or ''sidereal day''), i.e., the time that the objec ...

of 4.098 hours with a brightness variation of 0.25

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 ...

(). Previously, in May 2003, photometric observations made by Donald P. Pray at the Carbuncle Hill Observatory near Providence, Rhode Island, gave a synodic period of 4.096 hours and an amplitude of 0.40 in magnitude (). In addition astronomers 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 ...

found a period of 4.096 hours with an amplitude of 0.28 om May 2011 (), and French amateur astronomer René Roy obtained a period of 8.1922 hours (twice the period solution) with an amplitude of 0.36 ().

Poles

In 2016, an international study modeled a lightcurve with a concurring period of hours and found two spin axes of (269.0°, −31.0°) and (103.0°, −59.0°) in

ecliptic coordinates In astronomy, the ecliptic coordinate system is a celestial coordinate system commonly used for representing the apparent positions, orbits, and pole orientations of Solar System objects. Because most planets (except Mercury) and many small So ...

(λ, β) ().

Diameter and albedo

According to the survey carried out by the

NEOWISE Wide-field Infrared Survey Explorer (WISE, observatory code C51, Explorer 92 and MIDEX-6) was a NASA infrared astronomy space telescope in the Explorers Program launched in December 2009.. . WISE discovered thousands of minor planets and nu ...

mission of NASA's

Wide-field Infrared Survey Explorer Wide-field Infrared Survey Explorer (WISE, List of observatory codes, observatory code C51, Explorer 92 and MIDEX-6) was a NASA infrared astronomy Space observatory, space telescope in the Explorers Program launched in December 2009.. . WISE L ...

, ''Valdivia'' measures between 9.13 and 11.679 kilometers in diameter and its surface has an

albedo Albedo ( ; ) is the fraction of sunlight that is Diffuse reflection, diffusely reflected by a body. It is measured on a scale from 0 (corresponding to a black body that absorbs all incident radiation) to 1 (corresponding to a body that reflects ...

between 0.205 and 0.404, while the Japanese Akari satellite found an albedo of 0.244 and a diameter of 10.73 kilometers. The ''Collaborative Asteroid Lightcurve Link'' assumes an albedo of 0.10 – a compromise value between the

carbonaceous Carbonaceous refers to something relating to, containing, or composed of carbon. It is a descriptor used for the attribute of any substance rich in carbon. Particularly, ''carbonaceous hydrocarbons'' are very unsaturated, high- molecular-weight h ...

(0.057) and stony (0.20) asteroids – and calculates a diameter of 17.52 kilometers based on an absolute magnitude of 11.9.

References

External links

Lightcurve Database Query
(LCDB), at ''www.minorplanet.info''
Dictionary of Minor Planet Names
Google books

– ''Geneva Observatory'',

Raoul Behrend This is a list of minor-planet discoverers credited by the Minor Planet Center with the discovery of one or several minor planets (such as near-Earth and main-belt asteroids, Jupiter trojans and distant objects). , the discovery of 612,011 nu ...

Discovery Circumstances: Numbered Minor Planets (1)-(5000)
– Minor Planet Center * * {{DEFAULTSORT:Valdivia 002741 Discoveries by Carlos Torres (astronomer) Discoveries by Sergio Barros Named minor planets 19751201