7816 Hanoi

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7816 Hanoi
Discovery [1]
Discovered by M. Koishikawa
Discovery site Ayashi Station (391)
Sendai Obs.
Discovery date 18 December 1987
MPC designation 7816 Hanoi
Named after
(Vietnamese capital)[2]
1987 YA · 1994 VB1
Orbital characteristics[1]
Epoch 31 July 2016 (JD 2457600.5)
Uncertainty parameter 0
Observation arc 28.29 yr (10,334 days)
Aphelion 2.9952 AU
Perihelion 1.6330 AU
2.3141 AU
Eccentricity 0.2943
3.52 yr (1,286 days)
0° 16m 48s / day
Inclination 2.3787°
Earth MOID 0.6380 AU
Physical characteristics
Dimensions 2.97 km (calculated)[3]
5.17±0.01 h[4]
5.18±0.02 h[5]
0.20 (assumed)[3]

7816 Hanoi, provisional designation 1987 YA, is a stony asteroid and Mars-crosser from the inner regions of the asteroid belt, approximately 3 kilometers in diameter. It was discovered by Japanese astronomer Masahiro Koishikawa at the Ayashi Station of the Sendai Astronomical Observatory, Japan, on 18 December 1987.[7]

The S-type asteroid orbits the Sun at a distance of 1.6–3.0 AU once every 3 years and 6 months (1,286 days). Its orbit has a high eccentricity of 0.29 and an inclination of 2° with respect to the ecliptic.[1] No precoveries were taken and the asteroid's observation arc begins with its discovery.[7]

In November 2011, a rotational light-curve for this asteroid was obtained from photometric observations made American astronomer by Brian Warner at the at his Palmer Divide Observatory in Colorado. The light-curve gave a rotation period of 5.18±0.02 hours with a brightness variation of 0.72 in magnitude (U=2+).[5] Ten years later, remeasurements of the original images rendered a slightly refined period of 5.17±0.01 and an amplitude of 0.77 (U=3-).[4] The Collaborative Asteroid Lightcurve Link assumes a standard albedo for stony asteroids of 0.20, and calculates a diameter of 3.0 kilometers, based on an absolute magnitude of 15.0.[3]

The minor planet was named after the city of Hanoi, capital of Vietnam, which the discoverer visited in 1997. Together with astronomer Yoshihide Kozai, after whom the minor planet 3040 Kozai is named, he assisted local astronomers install a Schmidt-Cassegrain and a refracting telescope at HNUE. The installed instrumentation was funded by the Japanese Sumitomo Foundation, with the intention to foster Vietnamese astronomical research.[2] Naming citation was published on 2 February 1999 (M.P.C. 33790).[8]

See also[edit]


  1. ^ a b c d e "JPL Small-Body Database Browser: 7816 Hanoi (1987 YA)" (2016-04-03 last obs.). Jet Propulsion Laboratory. Retrieved 26 May 2016. 
  2. ^ a b Schmadel, Lutz D. (2007). Dictionary of Minor Planet Names – (7816) Hanoi. Springer Berlin Heidelberg. p. 617. ISBN 978-3-540-00238-3. Retrieved 26 May 2016. 
  3. ^ a b c d e f "LCDB Data for (7816) Hanoi". Asteroid Lightcurve Database (LCDB). Retrieved 26 May 2016. 
  4. ^ a b Warner, Brian D. (January 2011). "Upon Further Review: V. An Examination of Previous Lightcurve Analysis from the Palmer Divide Observatory". The Minor Planet Bulletin. 38 (1): 63–65. Bibcode:2011MPBu...38...63W. ISSN 1052-8091. Retrieved 26 May 2016. 
  5. ^ a b Warner, B. D. (June 2002). "Asteroid Photometry at the Palmer Divide Observatory: Results for 620 Drakonia, 3447 Burkhalter, and 7816 Hanoi". The Minor Planet Bulletin. 29: 27–28. Bibcode:2002MPBu...29...27W. Retrieved 26 May 2016. 
  6. ^ Veres, Peter; Jedicke, Robert; Fitzsimmons, Alan; Denneau, Larry; Granvik, Mikael; Bolin, Bryce; et al. (November 2015). "Absolute magnitudes and slope parameters for 250,000 asteroids observed by Pan-STARRS PS1 - Preliminary results". Icarus. 261: 34–47. arXiv:1506.00762free to read. Bibcode:2015Icar..261...34V. doi:10.1016/j.icarus.2015.08.007. Retrieved 26 May 2016. 
  7. ^ a b "7816 Hanoi (1987 YA)". Minor Planet Center. Retrieved 26 May 2016. 
  8. ^ "MPC/MPO/MPS Archive". Minor Planet Center. Retrieved 26 May 2016. 

External links[edit]