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Discovery [1] | |
---|---|
Discovered by | J. Palisa |
Discovery site | Vienna Obs. |
Discovery date | 12 November 1885 |
Designations | |
(253) Mathilde | |
Pronunciation | /məˈtɪldə/ |
Named after | Mathilde Loewy |
A885 VA, 1915 TN 1949 OL1 | |
Main belt | |
Orbital characteristics [2] | |
Epoch 31 July 2016 (JD 2457600.5) | |
Uncertainty parameter 0 | |
Observation arc | 130.38 yr (47622 d) |
Aphelion | 3.35003411 AU (501.157970 Gm) |
Perihelion | 1.9467702 AU (291.23268 Gm) |
2.648402147 AU (396.1953219 Gm) | |
Eccentricity | 0.26492652 |
4.31 yr (1574.3 d) | |
Average orbital speed | 17.98 km/s [3] |
170.584348° | |
0° 13m 43.248s / day | |
Inclination | 6.7427122° |
179.58936° | |
157.39642° | |
Earth MOID | 0.939032 AU (140.4772 Gm) |
Jupiter MOID | 2.06073 AU (308.281 Gm) |
TJupiter | 3.331 |
Physical characteristics | |
Dimensions | 52.8 km [2] (66×48×46 km [4] ) |
Mass | (1.033±0.044)×1017 kg [5] |
Mean density | 1.3 g/cm3 [5] |
Equatorial surface gravity | 0.00989 m/s2 |
Equatorial escape velocity | 22.9 m/s |
417.7 h (17.40 d) [2] 17.406 ± 0.010 d [6] (17 d 9 h 45 min) | |
0.0436±0.004 [2] | |
Temperature | ≈ 174 [7] K |
Cb [2] | |
10.3 [2] | |
Mathilde (minor planet designation: 253 Mathilde) is an asteroid in the intermediate asteroid belt, approximately 50 kilometers in diameter, that was discovered by Austrian astronomer Johann Palisa at Vienna Observatory on 12 November 1885. It has a relatively elliptical orbit that requires more than four years to circle the Sun. This tumbling asteroid has an unusually slow rate of rotation, requiring 17.4 days to complete a 360° revolution about its axis. It is a primitive C-type asteroid, which means the surface has a high proportion of carbon; giving it a dark surface that reflects only 4% of the light that falls on it. [8]
Mathilde was visited by the NEAR Shoemaker spacecraft during June 1997, on its way to asteroid 433 Eros. During the little flyby, the spacecraft imaged a hemisphere of the asteroid, revealing many large craters that had gouged out depressions in the surface. It was the first carbonaceous asteroid to be explored and, until 21 Lutetia was visited in 2010, it was the largest asteroid to be visited by a spacecraft.
In 1880, Johann Palisa, the director of the Austrian Naval Observatory ( 538 ), was offered a position as an assistant at the newly completed Vienna Observatory. Although the job represented a demotion for Johann, it gave him access to the new 27-inch (690 mm) refractor, the largest telescope in the world at that time. By this point Johann had already discovered 27 asteroids, and he would employ the Vienna 27-inch (690 mm) and 12-inch (300 mm) instruments to find an additional 94 asteroids before he retired. [9]
Among his discoveries was the asteroid 253 Mathilde, found on November 12, 1885. The initial orbital elements of the asteroid were then computed by V. A. Lebeuf, another Austrian astronomer working at the Paris Observatory. [10] The name of the asteroid was suggested by Lebeuf, after Mathilde, the wife of Moritz Loewy —who was the vice director of the observatory in Paris. [1] [10]
In 1995, ground-based observations determined that Mathilde is a C-type asteroid. It was also found to have an unusually long period of rotation of 418 hours. [10]
On June 27, 1997, the NEAR Shoemaker spacecraft passed within 1,212 km of Mathilde while moving at a velocity of 9.93 km/s. This close approach allowed the spacecraft to capture over 500 images of the surface, [8] and provided data for more accurate determinations of the asteroid's dimensions and mass (based on gravitational perturbation of the spacecraft). [5] However, only one hemisphere of Mathilde was imaged during the fly-by. [11] This was only the third asteroid to be imaged from a nearby distance, following 951 Gaspra and 243 Ida.
Mathilde is very dark, with an albedo comparable to fresh asphalt, [12] and is thought to share the same composition as CI1 or CM2 carbonaceous chondrite meteorites, with a surface dominated by phyllosilicate minerals. [13] The asteroid has a number of extremely large craters, with the individual craters being named for coal fields and basins around the world. [14] The two largest craters, Ishikari (29.3 km) and Karoo (33.4 km), are as wide as the asteroid's average radius. [4] The impacts appear to have spalled large volumes off the asteroid, as suggested by the angular edges of the craters. [8] Uniformity in brightness and colour were visible in the craters and there was no appearance of layering, so the asteroid's interior must be very homogeneous. There are indications of material movement along the downslope direction. [4]
The density measured by NEAR Shoemaker, 1,300 kg/m3, is less than half that of a typical carbonaceous chondrite; this may indicate that the asteroid is very loosely packed rubble pile. [5] The same is true of several C-type asteroids studied by ground-based telescopes equipped with adaptive optics systems (45 Eugenia, 90 Antiope, 87 Sylvia and 121 Hermione). Up to 50% of the interior volume of Mathilde consists of open space. However, the existence of a 20-km-long scarp may indicate that the asteroid does have some structural strength, so it could contain some large internal components. [11] The low interior density is an inefficient transmitter of impact shock through the asteroid, which also helps to preserve the surface features to a high degree. [4]
Mathilde's orbit is eccentric, taking it to the outer reaches of the belt. Nonetheless, the orbit lies entirely between the orbits of Mars and Jupiter; it does not cross the planetary orbits. It also has one of the slowest rotation periods of the known asteroids—most asteroids have a rotation period in the range of 2–24 hours. [15] Because of the slow rotation rate, NEAR Shoemaker was sadly only able to photograph 60% of the asteroid's surface. The slow rate of rotation may be accounted for by a satellite orbiting the asteroid, but a search of the NEAR images revealed none larger than 10 km in diameter out to 20 times the radius of Mathilde. [16]
An asteroid is a minor planet—an object that is neither a true planet nor a comet—that orbits within the inner Solar System. They are rocky, metallic, or icy bodies with no atmosphere. The size and shape of asteroids vary significantly, ranging from small rubble piles under a kilometer across to Ceres, a dwarf planet almost 1000 km in diameter.
Eros is a stony asteroid of the Amor group, and the first discovered, and second-largest near-Earth object. It has an elongated shape and a volume-equivalent diameter of approximately 16.8 kilometers. Visited by the NEAR Shoemaker space probe in 1998, it became the first asteroid ever studied from its own orbit.
Near Earth Asteroid Rendezvous – Shoemaker, renamed after its 1996 launch in honor of planetary scientist Eugene Shoemaker, was a robotic space probe designed by the Johns Hopkins University Applied Physics Laboratory for NASA to study the near-Earth asteroid Eros from close orbit over a period of a year. It was the first spacecraft to orbit an asteroid and land on it successfully. In February 2000, the mission closed in on the asteroid and orbited it. On February 12, 2001, Shoemaker touched down on the asteroid and was terminated just over two weeks later.
Vesta is one of the largest objects in the asteroid belt, with a mean diameter of 525 kilometres (326 mi). It was discovered by the German astronomer Heinrich Wilhelm Matthias Olbers on 29 March 1807 and is named after Vesta, the virgin goddess of home and hearth from Roman mythology.
16 Psyche is a large M-type asteroid, which was discovered by the Italian astronomer Annibale de Gasparis, on 17 March 1852 and named after the Greek goddess Psyche. The prefix "16" signifies that it was the sixteenth minor planet in order of discovery. It is the largest and most massive of the M-type asteroids, and one of the dozen most massive asteroids. It has a mean diameter of approximately 220 kilometers (140 mi) and contains about one percent of the mass of the asteroid belt. It was thought to be the exposed core of a protoplanet, but recent observations cast doubt on that hypothesis. Psyche will be explored by NASA, with a spacecraft of the same name, marking the first time a manmade object will journey to a metallic asteroid, launched on 13 October 2023, with an expected arrival in 2029.
Pallas is the third-largest asteroid in the Solar System by volume and mass. It is the second asteroid to have been discovered, after Ceres, and is a likely remnant protoplanet. Like Ceres, it is believed to have a mineral composition similar to carbonaceous chondrite meteorites, though significantly less hydrated than Ceres. It is 79% the mass of Vesta and 22% the mass of Ceres, constituting an estimated 7% of the mass of the asteroid belt. Its estimated volume is equivalent to a sphere 507 to 515 kilometers in diameter, 90–95% the volume of Vesta.
Ida, minor planet designation 243 Ida, is an asteroid in the Koronis family of the asteroid belt. It was discovered on 29 September 1884 by Austrian astronomer Johann Palisa at Vienna Observatory and named after a nymph from Greek mythology. Later telescopic observations categorized Ida as an S-type asteroid, the most numerous type in the inner asteroid belt. On 28 August 1993, Ida was visited by the uncrewed Galileo spacecraft while en route to Jupiter. It was the second asteroid visited by a spacecraft and the first found to have a natural satellite.
Phobos is the innermost and larger of the two natural satellites of Mars, the other being Deimos. The two moons were discovered in 1877 by American astronomer Asaph Hall. It is named after Phobos, the Greek god of fear and panic, who is the son of Ares (Mars) and twin brother of Deimos.
Dawn is a retired space probe that was launched by NASA in September 2007 with the mission of studying two of the three known protoplanets of the asteroid belt: Vesta and Ceres. In the fulfillment of that mission—the ninth in NASA's Discovery Program—Dawn entered orbit around Vesta on July 16, 2011, and completed a 14-month survey mission before leaving for Ceres in late 2012. It entered orbit around Ceres on March 6, 2015. In 2017, NASA announced that the planned nine-year mission would be extended until the probe's hydrazine fuel supply was depleted. On November 1, 2018, NASA announced that Dawn had depleted its hydrazine, and the mission was ended. The derelict probe remains in a stable orbit around Ceres.
Lutetia is a large M-type asteroid in the main asteroid belt. It measures about 100 kilometers in diameter. It was discovered in 1852 by Hermann Goldschmidt, and is named after Lutetia, the Latin name of Paris.
2867 Šteins is an irregular, diamond-shaped background asteroid from the inner regions of the asteroid belt, approximately 5 kilometers in diameter. It was discovered on 4 November 1969 by Soviet astronomer Nikolai Chernykh at the Crimean Astrophysical Observatory in Nauchnij on the Crimean peninsula. In September 2008, ESA's spacecraft Rosetta flew by Šteins, making it one of few minor planets ever visited by a spacecraft. The bright E-type asteroid features 23 named craters and has a rotation period of 6.05 hours. It was named for Soviet Latvian astronomer Kārlis Šteins.
Johann Palisa 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 Gellivara in 1923. Some of his notable discoveries include 153 Hilda, 216 Kleopatra, 243 Ida, 253 Mathilde, 324 Bamberga, and the near-Earth asteroid 719 Albert. Palisa made his discoveries without the aid of photography, and he remains the most successful visual (non-photographic) asteroid discoverer of all time. He was awarded the Valz Prize from the French Academy of Sciences in 1906. The asteroid 914 Palisana, discovered by Max Wolf in 1919, and the lunar crater Palisa were named in his honour.
4660 Nereus, provisional designation 1982 DB, is a small asteroid. It was discovered by Eleanor F. Helin on 28 February 1982, approximately a month after it passed 4.1 million km (11 LD) from Earth.
716 Berkeley is a background asteroid from the central regions of the asteroid belt. It was discovered by Austrian astronomer Johann Palisa at the Vienna Observatory on 30 July 1911. The stony S-type asteroid has a rotation period of 15.6 hours and measures approximately 21 kilometers in diameter. It was named after the city of Berkeley, California, where the discoverer's colleague Armin Otto Leuschner (1868–1953) was the director of the local observatory.
Ceres is a dwarf planet in the middle main asteroid belt between the orbits of Mars and Jupiter. It was the first known asteroid, discovered on 1 January 1801 by Giuseppe Piazzi at Palermo Astronomical Observatory in Sicily, and announced as a new planet. Ceres was later classified as an asteroid and then a dwarf planet, the only one inside Neptune's orbit.
2019 van Albada, provisional designation 1935 SX1, is a stony Florian asteroid and former spacecraft target from the inner regions of the asteroid belt, approximately 8 kilometers in diameter. It was discovered on 28 September 1935, by Dutch astronomer Hendrik van Gent at Leiden Southern Station, annex to the Johannesburg Observatory in South Africa. The asteroid was later named after Gale Bruno van Albada.
951 Gaspra is an S-type asteroid that orbits very close to the inner edge of the asteroid belt. Gaspra was discovered by Russian astronomer G. N. Neujmin in 1916. Neujmin named it after Gaspra, a Black Sea retreat that was visited by his contemporaries, such as Gorky and Tolstoy.
Karoo is an impact crater on the asteroid 253 Mathilde, named for the Great Karoo Basin, a coal basin in South Africa. It is 33.4 kilometers in diameter and was the most prominent crater seen during NEAR Shoemaker's flyby of the asteroid.
152830 Dinkinesh (provisional designation 1999 VD57) is a binary main-belt asteroid about 790 meters (2,600 feet) in diameter. It was discovered by the Lincoln Near-Earth Asteroid Research (LINEAR) survey at Socorro, New Mexico on 4 November 1999. Dinkinesh, the name borrowed from an Ethiopian word for the Lucy fossil, was the first flyby target of NASA's Lucy mission, which approached 425 km (264 mi) from the asteroid on 1 November 2023. During the flyby, the Lucy spacecraft discovered that Dinkinesh has a contact-binary natural satellite, named Selam, which is 220 meters (720 ft) in diameter. Dinkinesh is the smallest main-belt asteroid explored by spacecraft yet, though some smaller near-Earth asteroids have also been explored.
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