140 Siwa is a large and dark

main-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 ...

asteroid An asteroid is a minor planet—an object larger than a meteoroid that is neither a planet nor an identified comet—that orbits within the Solar System#Inner Solar System, inner Solar System or is co-orbital with Jupiter (Trojan asteroids). As ...

that was discovered by Austrian astronomer

Johann Palisa Johann Palisa (6 December 1848 – 2 May 1925) was an Austrian astronomer, born in Troppau, Austrian Silesia, now Czech Republic. He was a prolific discoverer of asteroids, discovering 122 in all, from 136 Austria in 1874 to 1073 G ...

on October 13, 1874, and named after Živa (Šiwa), a

Slavic Slavic, Slav or Slavonic may refer to: Peoples * Slavic peoples, an ethno-linguistic group living in Europe and Asia ** East Slavic peoples, eastern group of Slavic peoples ** South Slavic peoples, southern group of Slavic peoples ** West Slav ...

goddess of

fertility Fertility in colloquial terms refers the ability to have offspring. In demographic contexts, fertility refers to the actual production of offspring, rather than the physical capability to reproduce, which is termed fecundity. The fertility rate ...

. The ''

Rosetta Rosetta ( ) or Rashid (, ; ) is a port city of the Nile Delta, east of Alexandria, in Egypt's Beheira governorate. The Rosetta Stone was discovered there in 1799. Founded around the 9th century on the site of the ancient town of Bolbitine, R ...

comet A comet is an icy, small Solar System body that warms and begins to release gases when passing close to the Sun, a process called outgassing. This produces an extended, gravitationally unbound atmosphere or Coma (cometary), coma surrounding ...

probe was to visit Siwa on its way to comet

46P/Wirtanen 46P/Wirtanen is a small short-period comet with a current orbital period of 5.4 years. It was the original target for close investigation by the ''Rosetta'' spacecraft, planned by the European Space Agency, but an inability to meet the launch ...

in July, 2008. However, the mission was rerouted to comet 67P/Churyumov-Gerasimenko and the flyby had to be abandoned. Attempts to measure the rotation period of this asteroid have produced inconsistent results ranging from 14.7 to 32 hours. Photometric observations of this asteroid at the Organ Mesa Observatory in

Las Cruces, New Mexico Las Cruces (; ; lit. 'the crosses') is the List of municipalities in New Mexico, second-most populous city in the U.S. state of New Mexico and the county seat, seat of Doña Ana County, New Mexico, Doña Ana County. As of the 2020 United States ce ...

during 2010 gave an irregular

light curve 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 ...

with a period of 34.407 ± 0.002 hours and a brightness variation of 0.05 ± 0.01 in

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 ...

. A 2004 study of the spectrum matched a typical

C-type asteroid C-type (carbonaceous ) asteroids are the most common variety, forming around 75% of known asteroids. They are volatile-rich and distinguished by a very low albedo because their composition includes a large amount of carbon, in addition to rocks ...

with typical

carbonaceous chondrite Carbonaceous chondrites or C chondrites are a class of chondritic meteorites comprising at least 8 known groups and many ungrouped meteorites. They include some of the most primitive known meteorites. The C chondrites represent only a small propo ...

makeup. There are no absorption features of

mafic A mafic mineral or rock is a silicate mineral or igneous rock rich in magnesium and iron. Most mafic minerals are dark in color, and common rock-forming mafic minerals include olivine, pyroxene, amphibole, and biotite. Common mafic rocks include ...

minerals found. The classification was later revised to a

P-type asteroid P-type (primitive-type) asteroids have low albedo and a featureless reddish spectrum. It has been suggested that they have a composition of organic-rich silicates, carbon and anhydrous silicates, possibly with water ice in their interior. P-type ...

References

External links

* * {{DEFAULTSORT:Siwa 000140 Discoveries by Johann Palisa Named minor planets 000140 000140 18741013