| Discovery[1] | |
|---|---|
| Discovered by | M. Koishikawa |
| Discovery site | Ayashi Station (391) Sendai Obs. |
| Discovery date | 18 December 1987 |
| Designations | |
| (7816) Hanoi | |
Named after | Hanoi (Vietnamese capital)[2] |
| 1987 YA · 1994 VB1 | |
| Mars-crosser[1][3] | |
| Orbital characteristics[1] | |
| Epoch 4 September 2017 (JD 2458000.5) | |
| Uncertainty parameter 0 | |
| Observation arc | 29.37 yr (10,728 days) |
| Aphelion | 2.9970AU |
| Perihelion | 1.6341 AU |
| 2.3156 AU | |
| Eccentricity | 0.2943 |
| 3.52yr (1,287 days) | |
| 184.18° | |
| 0° 16m 46.92s / day | |
| Inclination | 2.3838° |
| 222.96° | |
| 170.75° | |
| Physical characteristics | |
| Dimensions | 2.97 km(calculated)[3] |
| 5.17±0.01h[4] 5.18±0.02 h[5] | |
| 0.20(assumed)[3] | |
| S[3] | |
| 15.0[1][3] · 15.18±0.30[6] | |
7816 Hanoi, provisional designation1987 YA, is an eccentric stonyasteroid andMars-crosser from the inner regions of theasteroid belt, approximately 3 kilometers in diameter. It was discovered on 18 December 1987, by Japanese astronomerMasahiro Koishikawa at the Ayashi Station (391) of theSendai Astronomical Observatory, Japan, and later named after the Vietnamese capital ofHanoi.[2][7]
Hanoi orbits the Sun in theinner main-belt at a distance of 1.6–3.0 AU once every 3 years and 6 months (1,287 days). Its orbit has aneccentricity of 0.29 and aninclination of 2° with respect to theecliptic.[1] Noprecoveries were taken. The asteroid'sobservation arc begins with its official discovery observation.[7]
In November 2011, a rotationallightcurve ofHanoi was obtained from photometric observations made American astronomer byBrian Warner at his Palmer Divide Observatory in Colorado. The lightcurve gave arotation period of5.18±0.02 hours with a brightness variation of 0.72magnitude (U=2+).[5] Ten years later, remeasurements of the original images rendered a slightly refined period of5.17±0.01 and an amplitude of 0.77 (U=3-).[4]
TheCollaborative Asteroid Lightcurve Link assumes a standardalbedo forstony asteroids of 0.20, and calculates a diameter of 3.0 kilometers with anabsolute magnitude of 15.0.[3]
Thisminor planet was named after the city ofHanoi, capital of Vietnam, which the discoverer visited in 1997. Together with astronomer Yoshihide Kozai, after whom the minor planet3040 Kozai is named, he assisted local astronomers install aSchmidt-Cassegrain and arefracting telescope atHNUE. The installed instrumentation was funded by the Japanese Sumitomo Foundation, with the intention to foster Vietnamese astronomical research.[2] The official naming citation was published by theMinor Planet Center on 2 February 1999 (M.P.C. 33790).[8]
