Discovery [1] | |
---|---|
Discovered by | A. Massinger |
Discovery site | Heidelberg Obs. |
Discovery date | 15 April 1912 |
Designations | |
(732) Tjilaki | |
Pronunciation | Malay: [tʃiˈlaki] |
Named after | Cilaki River [2] [3] (River in Indonesia) |
A912 HK ·1958 FC 1912 OR | |
Orbital characteristics [4] | |
Epoch 31 May 2020 (JD 2459000.5) | |
Uncertainty parameter 0 | |
Observation arc | 106.66 yr (38,959 d) |
Aphelion | 2.5633 AU |
Perihelion | 2.3490 AU |
2.4561 AU | |
Eccentricity | 0.0436 |
3.85 yr (1,406 d) | |
359.80° | |
0° 15m 21.96s / day | |
Inclination | 10.994° |
173.35° | |
64.900° | |
Physical characteristics | |
Mean diameter | |
12.34±0.01 h [11] | |
Pole ecliptic latitude | |
732 Tjilaki ( prov. designation:A912 HKor1912 OR) is a dark background asteroid, approximately 36 kilometers (22 miles) in diameter, located in the inner region of the asteroid belt. It was discovered by German astronomer Adam Massinger at the Heidelberg Observatory on 15 April 1912, and later named after the Cilaki (Tjilaki) river in Indonesia. [1] [2] The dark D-type asteroid has a rotation period of 12.3 hours. It was an early candidate to be visited by the Rosetta spacecraft which eventually rendezvoused comet 67P/Churyumov–Gerasimenko. [11]
Tjilaki is a non-family asteroid of the main belt's background population when applying the hierarchical clustering method to its proper orbital elements. [5] [6] [7] It orbits the Sun in the inner asteroid belt at a distance of 2.3–2.6 AU once every 3 years and 10 months (1,406 days; semi-major axis of 2.46 AU). Its orbit has an eccentricity of 0.04 and an inclination of 11° with respect to the ecliptic. [4] The body's observation arc begins at Heidelberg Observatory on 28 August 1913, or 16 months after its official discovery observation. [1]
This minor planet was named after the Cilaki (Tjilaki) river in West Java, Indonesia. The river rises in the mountains where the city of Malabar (see asteroid 754 Malabar) is located. The naming was mentioned in The Names of the Minor Planets by Paul Herget in 1955 ( H 74 ). [2]
In the Phase A study of the Rosetta mission, Tjilaki was considered an alternative visiting target to comet 46P/Wirtanen. [11] However, both candidates were later abandoned in favor of comet 67P/Churyumov–Gerasimenko, which was visited by Rosetta in 2014. The retargeting was necessary as the spacecraft's launch window changed due to a delay caused by the launch failure of the Hot Bird 7 satellite on the maiden flight of the Ariane 5 ECA carrier rocket in 2002.
In both the Tholen- and SMASS-like taxonomic variants of the Small Solar System Objects Spectroscopic Survey (S3OS2), , Tjilaki is a dark D-type asteroid, uncommon in the inner but abundant in the outer asteroid belt as well as among the Jupiter trojan population. [6] [12] Polarimetric observations also determined a D-type. [13] [14]
In February 1996, a rotational lightcurve of Tjilaki was obtained from photometric observations over ten nights by European astronomers using the Dutch 0.9-metre Telescope and the Bochum 0.61-metre Telescope at La Silla Observatory in Chile. Lightcurve analysis gave a rotation period of 12.34±0.01 hours with a brightness variation of 0.19±0.02 magnitude ( U=3− ). [11]
In May 2012, astronomers at the Palomar Transient Factory measured a period of 12.277±0.0048 hours ( U=2 ). [14] [15] Additional observations were made by the TESS-team in January 2019, and by amateur astronomers Axel Martin and Rui Goncalves in May 2020, reporting a concurring period of (12.3286±0.0005) and (12.3216±0.00144) hours with an amplitude of (0.16±0.03) and (0.287±0.004) magnitude, respectively ( U=2/n.a. ). [16] [17]
In 2016, a modeled lightcurve gave a concurring sidereal period of 12.3411±0.0002 hours using data from the Uppsala Asteroid Photometric Catalogue, the Palomar Transient Factory survey, and individual observers, as well as sparse-in-time photometry from the NOFS, the Catalina Sky Survey, and the La Palma surveys ( 950 ). The study also determined two spin axes of (160.0°, 23.0°) and (353.0°, 24.0°) in ecliptic coordinates (λ, β). [18]
According to the surveys carried out by the NEOWISE mission of NASA's Wide-field Infrared Survey Explorer (WISE), the Japanese Akari satellite, and the Infrared Astronomical Satellite IRAS, Tjilaki measures (29.791±0.431), (36.49±0.43) and (37.61±1.6) kilometers in diameter and its surface has an albedo of (0.138±0.024), (0.070±0.002) and (0.0655±0.006), respectively. [8] [9] [10] The Collaborative Asteroid Lightcurve Link derives an albedo of 0.0763 and a diameter of 37.69 kilometers based on an absolute magnitude of 10.53. [14]
Alternative mean-diameters published by the WISE team include (36.76±11.57 km) and (37.96±9.94 km) with a corresponding albedo of (0.09±0.06) and (0.15±0.05). [6] [14] Two asteroid occultations on 20 June 2005 and on 28 July 2009, gave a best-fit ellipse dimension of (33.6 km × 33.6 km) and (37.7 km × 36.4 km), respectively, each with an intermediate quality rating of 2. [6] These timed observations are taken when the asteroid passes in front of a distant star. [6]
Xanthippe is a dark background asteroid from the central regions of the asteroid belt, approximately 120 kilometers in diameter. It was discovered on 22 November 1875, by Austrian astronomer Johann Palisa at the Austrian Naval Observatory, in what is now Croatia. It is named after Xanthippe, the wife of the Greek philosopher Socrates.
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777 Gutemberga is a dark and large background asteroid, approximately 66 kilometers in diameter, from the outer regions of the asteroid belt. It was discovered by German astronomer Franz Kaiser at the Heidelberg-Königstuhl State Observatory on 24 January 1914. The carbonaceous C-type asteroid (Cb) has a rotation period of 12.8 hours. It was named after Johannes Gutenberg, who introduced the printing press to Europe and started the Printing Revolution.
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882 Swetlana is a dark background asteroid from the outer region of the asteroid belt. It was discovered on 15 August 1917, by Russian astronomer Grigory Neujmin at the Simeiz Observatory on the Crimean peninsula. The X-type asteroid has a longer-than average rotation period of 29.9 hours and measures approximately 42 kilometers in diameter. The origin of the asteroid's name remains unknown.
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974 Lioba is a stony background asteroid from the central regions of the asteroid belt, approximately 25 kilometers in diameter. It was discovered on 18 March 1922, by astronomer Karl Reinmuth at the Heidelberg-Königstuhl State Observatory in southern Germany. The S-type asteroid has a longer than average rotation period of 38.7 hours. It was named after missionary Saint Leoba (Lioba).
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1806 Derice, provisional designation 1971 LC, is a stony Flora asteroid from the inner regions of the asteroid belt, approximately 10 kilometers in diameter. Discovered on 13 June 1971, at the Bickley site of the Perth Observatory in Western Australia, it was the first discovery of a minor planet ever made in Oceania. The asteroid was named after the wife of Dennis Harwood, staff member at Bickley.
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