Discovery [1] [2] | |
---|---|
Discovered by | E. W. Tempel |
Discovery site | Marseille Obs. |
Discovery date | 8 March 1861 |
Designations | |
(65) Cybele | |
Pronunciation | /ˈsɪbəliː/ [3] |
Named after | Cybele [4] (Hellenistic deity) |
1949 YQ | |
main belt ·(outer) [1] Cybele [5] | |
Adjectives | Cybelean /ˌsɪbəˈliːən/ , rarely Cybelian /sɪˈbɛliən/ |
Orbital characteristics | |
Epoch 4 September 2017 (JD 2458000.5) | |
Uncertainty parameter 0 | |
Observation arc | 155.98 yr (56,971 d) |
Aphelion | 3.8102 AU |
Perihelion | 3.0464 AU |
3.4283 AU | |
Eccentricity | 0.1114 |
6.35 yr (2,319 days) | |
168.06° | |
0° 9m 19.08s / day | |
Inclination | 3.5627° |
155.63° | |
102.37° | |
Physical characteristics | |
Dimensions | 297 km × 291 km × 213 km [6] |
263±3 km [6] | |
Mass | est. (14.8±1.8)×1018 kg [6] |
Mean density | 1.55±0.19 g/cm3 [6] |
3.98704 h [7] 4.036 h [8] 4.04 h [9] 4.04052 h [10] [11] 6.07 h [12] 6.07 h [13] 6.08±0.05 h [14] 6.081±0.001 h [lower-alpha 1] 6.0814±0.0001 h [15] 6.081434±0.000005 h [16] 6.082±0.001 h [17] | |
0.044 [18] 0.050±0.005 [19] 0.06±0.03 [20] 0.06±0.04 [21] 0.0706±0.003 [22] [23] | |
Tholen = P [1] SMASS = Xc [1] · X [23] B–V = 0.690 [1] U–B = 0.271 [1] V–R = 0.400±0.007 [24] | |
10.67 to 13.64 | |
6.58±0.06 [24] ·6.62 [1] [22] [23] [21] [18] ·6.88±0.26 [25] ·6.95 [20] | |
65 Cybele is one of the largest asteroids in the Solar System. It is located in the outer asteroid belt. It is thought to be a remnant primordial body. [6] It gives its name to the Cybele group of asteroids [5] that orbit outward from the Sun from the 2:1 orbital resonance with Jupiter. The X-type asteroid has a relatively short rotation period of 6.0814 hours. It was discovered by Wilhelm Tempel in 1861, and named after Cybele, the earth goddess.
Cybele was discovered on 8 March 1861, by German astronomer Wilhelm Tempel from the Marseilles Observatory in southeastern France. [2] A minor controversy arose from its naming process. Tempel had awarded the honour of naming the asteroid to Carl August von Steinheil in recognition of his achievements in telescope production. Von Steinheil elected to name it "Maximiliana" after the reigning monarch Maximilian II of Bavaria. At the time, asteroids were conventionally given classical names, and a number of astronomers protested this contemporary appellation. The name Cybele was chosen instead, referring to the Phrygian goddess of the earth. [4] (The previously discovered 45 Eugenia, 54 Alexandra, and 64 Angelina had nevertheless also been given non-classical names; 64 Angelina had also been discovered by Tempel, but its name stood despite similar protests.)
The first Cybelian stellar occultation was observed on 17 October 1979, in the Soviet Union. The asteroid appeared to have an irregular shape, with the longest chord being measured as 245 km, closely matching results determined by the IRAS satellite in 1983 (see below). During the same 1979 occultation, a hint of a possible 11 km wide minor-planet moon at 917 km distance was detected, [26] but has since never been corroborated. As of 2017, neither the Asteroid Lightcurve Data Base nor Johnston's archive consider Cybele to be a binary asteroid. [23] [27]
Mean diameter estimates for Cybele range between 218.56 and 300.54 kilometers. According to observations by the Infrared Astronomical Satellite IRAS in 1983, the asteroid has a diameter of 237.26 km. [22] The NEOWISE mission of NASA's Wide-field Infrared Survey Explorer gave a diameter of 218.56 and 276.58 km. [20] [21] The largest estimates of 300.54 km is from the Japanese Akari satellite. [18] In 2004, Müller estimated Cybele using thermophysical modelling (TPM) to have dimensions of 302 × 290 × 232 km, which corresponds to a mean-diameter of 273.0 km. [19]
Observations in 2021 show that Cybele's present shape very closely matches what would be expected if it were in hydrostatic equilibrium, in contrast to the other large Cybele asteroids 87 Sylvia and 107 Camilla. This suggests a transition point between irregular small asteroids and equilibrium larger bodies at around 1.5 × 1019 kg, and makes it possible that outer Solar System bodies at least 260 km in diameter might have formed in equilibrium (note Saturn IX Phoebe, which at 212 km diameter probably formed in equilibrium). However, it is not certain if Cybele's current shape is its primordial one, or if it is the result of a large impact as on the very round 10 Hygiea and 31 Euphrosyne. Today no Cybele family is observable, but since Cybele orbits in a rather unstable region, any such family would be dispersed within 2 billion years. Cybele's larger density compared to Sylvia and Camilla does somewhat favour the first hypothesis, though. (Sylvia and Camilla experienced impacts, as evidenced by their satellites and by the Sylvia family.) [28]
Examination of the asteroid's infrared spectrum shows an absorption feature that is similar to the one present in the spectrum of 24 Themis. This can be explained by the presence of water ice. The asteroid may be covered in a layer of fine silicate dust mixed with small amounts of water-ice and organic solids. [29]
On August 24, 2008, Cybele occulted 2UCAC 24389317, a 12.7-magnitude star in the constellation Ophiuchus which showed a long axis of at least 294 km. [30] On 11 October 2009, Cybele occulted a 13.4-magnitude star in the constellation Aquarius. [31]
71 Niobe is a stony Gallia asteroid and relatively slow rotator from the central regions of the asteroid belt, approximately 90 kilometers in diameter. It was discovered by the German astronomer Robert Luther on 13 August 1861, and named after Niobe, a character in Greek mythology. In 1861, the brightness of this asteroid was shown to vary by astronomer Friedrich Tietjen.
96 Aegle is a carbonaceous asteroid and the namesake of the Aegle family located in the outer regions of the asteroid belt, approximately 170 kilometers in diameter. It was discovered on 17 February 1868, by French astronomer Jérôme Coggia at the Marseille Observatory in southeastern France. The rare T-type asteroid has a rotation period of 13.8 hours and has been observed several times during occultation events. It was named after Aegle ("brightness"), one of the Hesperides from Greek mythology.
107 Camilla is one of the largest asteroids from the outermost edge of the asteroid belt, approximately 250 kilometers in diameter. It is a member of the Sylvia family and located within the Cybele group. It was discovered on 17 November 1868, by English astronomer Norman Pogson at Madras Observatory, India, and named after Camilla, Queen of the Volsci in Roman mythology. The X-type asteroid is a rare trinary asteroid with two minor-planet moons discovered in 2001 and 2016, respectively. It is elongated in shape and has a short rotation period of 4.8 hours.
182 Elsa is a Massalia or background asteroid from the inner regions of the asteroid belt, approximately 44 kilometers in diameter. It was discovered on 7 February 1878, by Austrian astronomer Johann Palisa at the Austrian Naval Observatory in today's Croatia. The S-type asteroid has a very long rotation period of 80 hours and likely an elongated shape. The origin of its name is uncertain.
487 Venetia, provisional designation 1902 JL, is a rare-type stony asteroid from the middle regions of the asteroid belt, approximately 63 kilometers in diameter. It was discovered on 9 July 1902, by Italian astronomer Luigi Carnera at Heidelberg Observatory in southwest Germany. It was later named for the Italian Veneto region where the city of Venice is located.
692 Hippodamia, provisional designation 1901 HD, is a stony asteroid from the outer region of the asteroid belt, about 45 kilometers in diameter. It was discovered on 5 November 1901, by the German astronomers Max Wolf and August Kopff at Heidelberg Observatory in southern Germany. Nine years later, the body was rediscovered by August Kopff at its apparition in 1910.
749 Malzovia is a stony background asteroid from the inner regions of the asteroid belt, approximately 11 kilometers in diameter. It was discovered on 5 April 1913, by Russian astronomer Sergey Belyavsky at the Simeiz Observatory on the Crimean peninsula. The elongated S-type asteroid has a rotation period of 5.9 hours. It was named after Russian amateur astronomer Nikolai Maltsov who founded the discovering Simeïs Observatory in 1900.
1219 Britta, provisional designation 1932 CJ, is a stony background asteroid from the inner regions of the asteroid belt, approximately 11 kilometers in diameter. It was discovered on 6 February 1932, by German astronomer Max Wolf at the Heidelberg-Königstuhl State Observatory in southern Germany. The likely elongated S-type asteroid has a rotation period of 5.57 hours. Any reference of its name to a person is unknown.
1168 Brandia, provisional designation 1930 QA, is a stony Eunomian asteroid from the central regions of the asteroid belt, approximately 10 kilometers in diameter. Discovered by astronomer Eugène Delporte at Uccle Observatory in 1930, the asteroid was later named after mathematician Eugène Brand.
1404 Ajax is a carbonaceous Jupiter trojan from the Greek camp, approximately 83 kilometers kilometers in diameter. It was discovered on 17 August 1936, by German astronomer Karl Reinmuth at Heidelberg Observatory in southern Germany, and named after the legendary warrior Ajax from Greek mythology. The assumed C-type asteroid belongs to the 40 largest Jupiter trojans and has a longer than average rotation period of 29.4 hours.
1437 Diomedes is a large Jupiter trojan from the Greek camp, approximately 150 kilometers in diameter. It was discovered on 3 August 1937, by astronomer Karl Reinmuth at the Heidelberg-Königstuhl State Observatory in southwest Germany. The dark D/P-type asteroid belongs to the largest Jupiter trojans and has a notably elongated shape and a longer than average rotation period of 24.49 hours. Diomedes was the first Jupiter trojan successfully observed during an occultation event of star. It was named after the hero Diomedes from Greek mythology.
2797 Teucer is a large Jupiter trojan from the Greek camp, approximately 110 kilometers in diameter. It was discovered on 4 June 1981, by American astronomer Edward Bowell at the Anderson Mesa Station near Flagstaff, Arizona, in the United States. The dark D-type asteroid belongs to the 20 largest Jupiter trojans and has a rotation period of 10.15 hours. It was named after the Greek hero and great archer, Teucer.
1943 Anteros, provisional designation 1973 EC, is a spheroidal, rare-type asteroid and near-Earth object of the Amor group, approximately 2 kilometers in diameter.
1580 Betulia, provisional designation 1950 KA, is an eccentric, carbonaceous asteroid, classified as near-Earth object of the Amor group, approximately 4.2 kilometers in diameter. It was discovered on 22 May 1950, by South African astronomer Ernest Johnson at the Union Observatory in Johannesburg. The asteroid was named for Betulia Toro, wife of astronomer Samuel Herrick.
1665 Gaby, provisional designation 1930 DQ, is a stony asteroid and a relatively slow rotator from the inner regions of the asteroid belt, approximately 11 kilometers in diameter. It was discovered on 27 February 1930, by German astronomer Karl Reinmuth at Heidelberg Observatory in southern Germany. It was later named after Gaby Reinmuth, the discoverer's daughter-in-law.
1772 Gagarin is a stony background asteroid from the central region of the asteroid belt, approximately 9 kilometers in diameter. It was discovered on 6 February 1968, by Russian astronomer Lyudmila Chernykh at the Crimean Astrophysical Observatory in Nauchnyj, on the Crimean Peninsula. The asteroid was named after cosmonaut Yuri Gagarin.
2895 Memnon is a dark Jupiter trojan from the Trojan camp, approximately 56 kilometers in diameter. It was discovered on 10 January 1981, by American astronomer Norman Thomas at Lowell's Anderson Mesa Station near Flagstaff, Arizona, in the United States. The assumed C-type asteroid has a rotation period of 7.5 hours and belongs to the 80 largest Jupiter trojans. It was named after King Memnon from Greek mythology.
1389 Onnie, provisional designation 1935 SS1, is a stony Koronian asteroid from the outer region of the asteroid belt, approximately 13 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.
1902 Shaposhnikov is a dark Hilda asteroid from the outermost region of the asteroid belt, approximately 92 kilometers in diameter. It was discovered on 18 April 1972, by Russian astronomer Tamara Smirnova at the Crimean Astrophysical Observatory in Nauchnyj, on the Crimean peninsula. The asteroid was named after Soviet astronomer and WWII casualty Vladimir Shaposhnikov. It was one of the last larger asteroids discovered in the main belt.
1709 Ukraina, provisional designation 1925 QA, is a stony asteroid from the inner regions of the asteroid belt, approximately 9 kilometers in diameter. It was discovered on 16 August 1925, by Soviet astronomer Grigory Shajn at Simeiz Observatory on the Crimean peninsula. It was named in honor of Ukraine.