6250 Saekohayashi

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6250 Saekohayashi
Discovery [1]
Discovered by E. F. Helin
Discovery site Palomar Obs.
Discovery date 2 November 1991
MPC designation (6250) Saekohayashi
Named after
Saeko Hayashi
(Japanese astronomer)[2]
1991 VX1 · 1983 VP5
main-belt · (inner)[1]
Orbital characteristics[1]
Epoch 4 September 2017 (JD 2458000.5)
Uncertainty parameter 0
Observation arc 33.56 yr (12,259 days)
Aphelion 2.0701 AU
Perihelion 1.7950 AU
1.9326 AU
Eccentricity 0.0712
2.69 yr (981 days)
0° 22m 0.84s / day
Inclination 19.788°
Physical characteristics
Dimensions 3.67 km (calculated)[3]
82.6±0.5 h[4]
0.30 (assumed)[3]
14.1[1][3] · 14.17±0.26[5]

6250 Saekohayashi, provisional designation 1991 VX1, is a bright Hungaria asteroid and relatively slow rotator from the inner regions of the asteroid belt, approximately 3.7 kilometers in diameter. It was discovered on 2 November 1991, by American astronomer Eleanor Helin at Palomar Observatory in California, and later named after Japanese astronomer Saeko Hayashi.[2]

Orbit and classification[edit]

Saekohayashi 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 1.8–2.1 AU once every 2 years and 8 months (981 days). Its orbit has an eccentricity of 0.07 and an inclination of 20° with respect to the ecliptic.[1]

In November 1983, it was first identified as 1983 VP5 at the Karl Schwarzschild Observatory, extending the body's observation arc by 8 years prior to its official discovery observation at Palomar.[2]

Physical characteristics[edit]

Slow rotation and shape[edit]

In 2009, a rotational lightcurve of Saekohayashi was obtained by American astronomer Brian Warner at his Palmer Divide Observatory, Colorado. It gave a long rotation period of 82.6±0.5 hours with a high brightness variation of 0.78 magnitude (U=2+).[4] A high brightness amplitude typically indicates that the body has a non-spheroidal shape. While not being a slow rotator, it has a notably longer than average period.

Diameter and albedo[edit]

The Collaborative Asteroid Lightcurve Link assumes a high albedo of 0.30, typical for E-type asteroids, and calculates a diameter of 3.7 kilometers with an absolute magnitude of 14.1.[3]


This minor planet was named after Japanese astronomer Saeko S. Hayashi (born 1958), associate professor at the National Astronomical Observatory of Japan, who works with the Subaru Telescope. Her research includes the formation processes of planetary systems. Saeko is also dedicated to the popularization of astronomy in Hawaii and Japan and is an active member of the International Astronomical Union.[1][6] The official naming citation was published by the Minor Planet Center 15 February 1995 (M.P.C. 24730).[7]


  1. ^ a b c d e f "JPL Small-Body Database Browser: 6250 Saekohayashi (1991 VX1)" (2017-06-02 last obs.). Jet Propulsion Laboratory. Retrieved 21 June 2017. 
  2. ^ a b c d "6250 Saekohayashi (1991 VX1)". Minor Planet Center. Retrieved 1 May 2016. 
  3. ^ a b c d e f "LCDB Data for (6250) Saekohayashi". Asteroid Lightcurve Database (LCDB). Retrieved 1 May 2016. 
  4. ^ a b Warner, Brian D. (October 2009). "Asteroid Lightcurve Analysis at the Palmer Divide Observatory: 2009 March-June". The Minor Planet Bulletin. 36 (4): 172–176. arXiv:1203.4336Freely accessible. Bibcode:2009MPBu...36..172W. doi:10.1016/j.pss.2012.03.009. ISSN 1052-8091. Retrieved 7 January 2016. 
  5. ^ 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:1506.00762Freely accessible. Bibcode:2015Icar..261...34V. doi:10.1016/j.icarus.2015.08.007. Retrieved 1 May 2016. 
  6. ^ "Saeko S. Hayashi". IAU – International Astronomical Union. 29 September 2015. Retrieved 7 January 2016. 
  7. ^ "MPC/MPO/MPS Archive". Minor Planet Center. Retrieved 13 August 2016. 

External links[edit]