astro.wikisort.org - Asteroid

9084 Achristou, provisional designation 1995 CS₁, is a stony Hungaria asteroid from the innermost regions of the asteroid belt, about 1.9 kilometers in diameter. It was discovered by British astronomer David J. Asher at Siding Spring Observatory in New South Wales, Australia, on 3 February 1995.[8] The asteroid was named after British planetary astronomer Apostolos Christou.[2]

9084 Achristou

Discovery [1]
Discovered by	D. J. Asher
Discovery site	Siding Spring Obs.
Discovery date	3 February 1995
Designations
MPC designation	(9084) Achristou
Named after	Apostolos Christou (British astronomer)[2]
Alternative designations	1995 CS1 · 1980 GV1
Minor planet category	main-belt · Hungaria [3]
Orbital characteristics [1]
Epoch 4 September 2017 (JD 2458000.5)
Uncertainty parameter 0
Observation arc	36.64 yr (13,381 days)
Aphelion	2.0048 AU
Perihelion	1.7145 AU
Semi-major axis	1.8597 AU
Eccentricity	0.0780
Orbital period (sidereal)	2.54 yr (926 days)
Mean anomaly	206.11°
Mean motion	0° 23m 18.96s / day
Inclination	23.098°
Longitude of ascending node	197.54°
Argument of perihelion	72.116°
Earth MOID	0.7794 AU
Physical characteristics
Dimensions	1.76 km (calculated)[3] 1.916±0.367 km[4][5]
Synodic rotation period	8.84±0.02 h[6][lower-alpha 1]
Geometric albedo	0.30 (assumed)[3] 0.333±0.078[4][5]
Spectral type	E [3]
Absolute magnitude (H)	15.7[1][3] · 15.4[4] · 16.08±0.28[7]

Orbit and classification

Achristou is a member of the Hungaria family, which form the innermost dense concentration of asteroids in the Solar System. It orbits the Sun at a distance of 1.7–2.0 AU once every 2 years and 6 months (926 days). Its orbit has an eccentricity of 0.08 and an inclination of 23° with respect to the ecliptic.[1] In April 1980, it was first identified as 1980 GV₁ at Palomar Observatory, extending the body's observation arc by 15 years prior to its official discovery observation at Siding Spring.[8]

Physical characteristics

Achristou has been characterized as a bright E-type asteroid.[3]

Rotation period

In May 2013, a rotational lightcurve of Achristou was obtained from photometric observations by American astronomer Robert Stephens at the Center for Solar System Studies (U81) in California. Lightcurve analysis gave a rotation period of 8.84 hours with a low brightness variation of 0.09 magnitude (U=2+).[6][lower-alpha 1]

Diameter and albedo

Based on the survey carried out by the NEOWISE mission of NASA's space-based Wide-field Infrared Survey Explorer, Achristou measures 1.9 kilometers in diameter and its surface has an albedo of 0.33,[4][5] while the Collaborative Asteroid Lightcurve Link assumes an albedo of 0.30 and calculates a diameter of 1.8 kilometers with an absolute magnitude of 15.7.[3]

Naming

This minor planet was named after Apostolos Christou (born 1968), planetary astronomer and programmer at the North Irish Armagh Observatory, after which the minor planet 10502 Armaghobs was named. His field or research include minor planets in co-orbit with Venus, designing near-Earth asteroids missions, the dwarf planet 1 Ceres, meteor impacts on Venus, as well as the irregular satellite families of the outer planets.[2] The official naming citation was published by the Minor Planet Center on 23 May 2005 (M.P.C. 54173).[9]

Notes

References

External links

• Apostolos Christou, at Armagh Observatory, 7 Nov 2013
• 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
• 9084 Achristou at AstDyS-2, Asteroids—Dynamic Site
  • Ephemeris · Observation prediction · Orbital info · Proper elements · Observational info
• 9084 Achristou at the JPL Small-Body Database
  • Close approach · Discovery · Ephemeris · Orbit diagram · Orbital elements · Physical parameters

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