| Discovery[1] | |
|---|---|
| Discovered by | Y. C. Chang |
| Discovery site | Yerkes Obs. |
| Discovery date | 25 October 1928 |
| Designations | |
| (3789) Zhongguo | |
Named after | China[1] (Chinese transliteration) |
| 1928 UF · 1928 WC 1975 VH1 · 1981 WY6 1986 QK1 | |
| main-belt · (outer)[2] Zhongguo[3] | |
| Orbital characteristics[4] | |
| Epoch 23 March 2018 (JD 2458200.5) | |
| Uncertainty parameter 0 | |
| Observation arc | 89.57yr (32,717 d) |
| Aphelion | 3.8904AU |
| Perihelion | 2.6803 AU |
| 3.2854 AU | |
| Eccentricity | 0.1842 |
| 5.95 yr (2,175 d) | |
| 70.348° | |
| 0° 9m 55.8s / day | |
| Inclination | 2.7466° |
| 86.955° | |
| 313.35° | |
| Physical characteristics | |
| 14.01±0.18 km[5] | |
| 3.840±0.0005 h[2][6] | |
| 0.099±0.013[5] | |
| T(S3OS2-TH)[7][8] Xk(S3OS2-BB)[7][8] | |
| 12.7[1][4] | |
3789 Zhongguo, provisional designation1928 UF, is a resonantasteroid from outermost region of theasteroid belt, approximately 14 kilometers (8.7 miles) in diameter. It was discovered in 1928 by Chinese astronomerZhang Yuzhe at theYerkes Observatory in Williams Bay, Wisconsin, in the United States.[1] Originally named "China", the asteroidbecame lost and its name was transferred to another asteroid. After its re-discovery in 1986, it was namedZhongguo, which is the Chinese word for "China".[1] TheT/Xk-type asteroid is the namesake of the resonantZhongguo group, located in the asteroid belt'sHecuba gap. It has a shortrotation period of 3.8 hours.[2]
While studying in Chicago, Chinese astronomerZhang Yuzhe observed an unknown asteroid, provisionally designated1928 UF for the first time on 25 October 1928. After it was (prematurely) given the number 1125, he named it "China" or "中国" (Zhōngguó) in honor of his native country. As it was not observed beyond its initial appearance, a precise orbit could not be calculated, and as a consequence, it became alost asteroid.
In 1957, thePurple Mountain Observatory in China discovered another asteroid,1957 UN1. With the consent of Zhang Yuzhe, the designation1125 China was transferred from the 1928-lost asteroid to this newly discovered one. However, in August 1986, the newly observed object1986 QK1 was identified as the rediscovery of the originally lost asteroid. On 31 May 1988 its official nameZhongguo was published by theMinor Planet Center (M.P.C. 13179).[1][9]
Zhongguo is a non-family asteroid from the main belt'sbackground population.[10] It orbits the Sun in theouter main-belt at a distance of 2.7–3.9 AU once every 5 years and 11 months (2,175 days;semi-major axis of 3.29 AU). Its orbit has aneccentricity of 0.18 and aninclination of 3° with respect to theecliptic.[4] The body'sobservation arc begins at Williams Bay in November 1928, eleven days after its official discovery observation.[1]
It is also the namesake of theZhongguo asteroids, adynamical group with rather stableorbits. The group is located in theHecuba gap – one of the largestKirkwood gaps in the main belt at 3.27 AU – and stays in a 2:1mean motion resonance with the gas giantJupiter.[10] It occupies a similar proper element space as theGriqua asteroids. Both the Zhongguos and Griquas mark the outer rim of the asteroid belt. Further out are theCybele asteroids, which are sometimes described as the "last outpost" of the asteroid belt. They are followed in turn by the resonantHilda asteroids (3:2) andJupiter trojans (1:1).
Zhongguo is classified as aT-type andX/k-subtype in the Tholen- and SMASS-like taxonomy of theSmall Solar System Objects Spectroscopic Survey (S3OS2), respectively.[7][8]
According to the survey carried out by theNEOWISE mission of NASA'sWide-field Infrared Survey Explorer,Zhongguo measures 14.01 kilometers in diameter and its surface has analbedo of 0.099,[5] while theCollaborative Asteroid Lightcurve Link assumes a standard albedo for acarbonaceous asteroidof 0.057 and calculates a diameter of 12.71 kilometers based on anabsolute magnitude of 13.21.[2]
In January 2012, a rotationallightcurve ofZhongguo obtained fromphotometric observations by astronomers at thePalomar Transient Factory in California. It gave arotation period of3.840±0.0005 hours with a brightness amplitude of 0.24magnitude (U=2).[2][6]
