astro.wikisort.org - Asteroid

7816 Hanoi, provisional designation 1987 YA, is an eccentric stony asteroid and Mars-crosser from the inner regions of the asteroid belt, approximately 3 kilometers in diameter. It was discovered on 18 December 1987, by Japanese astronomer Masahiro Koishikawa at the Ayashi Station (391) of the Sendai Astronomical Observatory, Japan, and later named after the Vietnamese capital of Hanoi.[2][7]

7816 Hanoi

Discovery [1]
Discovered by	M. Koishikawa
Discovery site	Ayashi Station (391) Sendai Obs.
Discovery date	18 December 1987
Designations
MPC designation	(7816) Hanoi
Named after	Hanoi (Vietnamese capital)[2]
Alternative designations	1987 YA · 1994 VB1
Minor planet category	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	2.9970 AU
Perihelion	1.6341 AU
Semi-major axis	2.3156 AU
Eccentricity	0.2943
Orbital period (sidereal)	3.52 yr (1,287 days)
Mean anomaly	184.18°
Mean motion	0° 16m 46.92s / day
Inclination	2.3838°
Longitude of ascending node	222.96°
Argument of perihelion	170.75°
Physical characteristics
Dimensions	2.97 km (calculated)[3]
Synodic rotation period	5.17±0.01 h[4] 5.18±0.02 h[5]
Geometric albedo	0.20 (assumed)[3]
Spectral type	S [3]
Absolute magnitude (H)	15.0[1][3] · 15.18±0.30[6]

Orbit and classification

Hanoi orbits the Sun in the inner main-belt at a distance of 1.6–3.0 AU once every 3 years and 6 months (1,287 days). Its orbit has an eccentricity of 0.29 and an inclination of 2° with respect to the ecliptic.[1] No precoveries were taken. The asteroid's observation arc begins with its official discovery observation.[7]

Physical characteristics

Lightcurves

In November 2011, a rotational lightcurve of Hanoi was obtained from photometric observations made American astronomer by Brian Warner at his Palmer Divide Observatory in Colorado. The lightcurve gave a rotation period of 5.18±0.02 hours with a brightness variation of 0.72 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]

Diameter and albedo

The Collaborative Asteroid Lightcurve Link assumes a standard albedo for stony asteroids of 0.20, and calculates a diameter of 3.0 kilometers with an absolute magnitude of 15.0.[3]

Naming

This 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] The official naming citation was published by the Minor Planet Center on 2 February 1999 (M.P.C. 33790).[8]

See also

• List of astronomical objects discovered by Masahiro Koishikawa

References

External links

• The Palmer Divide Observatory: Tour given by Brian Warner on YouTube (time 4:03 min.)
• Lightcurve plot of 7816 Hanoi, Palmer Divide Observatory, B. D. Warner (2001)
• Asteroid Lightcurve Database (LCDB), query form (info Archived 16 December 2017 at the Wayback Machine)
• Dictionary of Minor Planet Names, Google books
• Asteroids and comets rotation curves, CdR – Observatoire de Genève, Raoul Behrend
• Discovery Circumstances: Numbered Minor Planets (5001)-(10000) – Minor Planet Center
• 7816 Hanoi at AstDyS-2, Asteroids—Dynamic Site
  • Ephemeris · Observation prediction · Orbital info · Proper elements · Observational info
• 7816 Hanoi at the JPL Small-Body Database
  • Close approach · Discovery · Ephemeris · Orbit diagram · Orbital elements · Physical parameters

На других языках

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- [en] 7816 Hanoi

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[ru] (7816) Ханой

(7816) Ханой (лат. Hanoi) — астероид, относящийся к группе астероидов пересекающих орбиту Марса. Он был открыт 18 декабря 1987 года японским астрономом М. Коисикава в обсерватории Сендай и назван в честь столицы Вьетнама города Ханой[1].

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