1429 Pemba, provisional designation , is a stony background asteroid from the central 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, c ...

, approximately 10 kilometers in diameter. It was discovered on 2 July 1937, by South African astronomer Cyril Jackson at the Union Observatory in Johannesburg. The asteroid was named for the

Pemba Island Pemba Island ( ar, الجزيرة الخضراء ''al-Jazīra al-khadrā'', literally "The Green Island"; sw, Pemba kisiwa) is a Tanzanian island forming part of the Zanzibar Archipelago, lying within the Swahili Coast in the Indian Ocean. Geo ...

off the coast of Tanzania.

Orbit and classification

''Pemba'' is a non-

family Family (from la, familia) is a group of people related either by consanguinity (by recognized birth) or affinity (by marriage or other relationship). The purpose of the family is to maintain the well-being of its members and of society. Idea ...

asteroid from the main belt's background population. It orbits the Sun in the central main-belt at a distance of 1.7–3.4 AU once every 4 years and 1 month (1,492 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 0.33 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 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 agains ...

. 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 Johannesburg.

Physical characteristics

''Pemba'' is an assumed stony

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 secon ...

Rotation period

In September 1982, 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 freq ...

of ''Pemba'' was obtained from photometric observations. Analysis of the fragmentary lightcurve gave a rotation period of 20 hours with a brightness amplitude of 0.3

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 ...

(). As of 2017, no secure period has been determined.

Diameter and albedo

According to the surveys carried out by the Japanese Akari satellite and 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 201 ...

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 201 ...

, ''Pemba'' measures between 8.71 and 10.75 kilometers in diameter and its surface has an

albedo Albedo (; ) is the measure of the diffuse reflection of 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 that refl ...

between 0.1316 and 0.196. The ''Collaborative Asteroid Lightcurve Link'' adopts

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 ...

's revised WISE results, that is, an albedo of 0.1316 and a diameter of 10.37 kilometers based on an

absolute magnitude Absolute magnitude () is a measure of the luminosity of a celestial object on an inverse logarithmic astronomical magnitude scale. An object's absolute magnitude is defined to be equal to the apparent magnitude that the object would have if it ...

of 12.74.

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 ''mino ...

was named for the

, Tanzania, part of the

Zanzibar Archipelago The Zanzibar Archipelago ( ar, أرخبيل زنجبار, sw, Funguvisiwa la Zanzibar) consists of several islands lying off the coast of East Africa south of the Somali sea. The archipelago is also known as the Spice Islands. There are four ...

, which was once under the rule of the

Sultan of Zanzibar The sultans of Zanzibar ( ar, سلاطين زنجبار) were the rulers of the Sultanate of Zanzibar, which was created on 19 October 1856 after the death of Said bin Sultan, who had ruled Oman and Zanzibar as the sultan of Oman since 1804. Th ...

. It is located off the East Coast of Africa in the

Indian Ocean The Indian Ocean is the third-largest of the world's five oceanic divisions, covering or ~19.8% of the water on Earth's surface. It is bounded by Asia to the north, Africa to the west and Australia to the east. To the south it is bounded by t ...

. The official was published by the Minor Planet Center in April 1953 ().

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:Pemba 001429 Discoveries by Cyril Jackson (astronomer) Named minor planets 19370702