1999 Hirayama

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1999 Hirayama
Discovery [1]
Discovered by L. Kohoutek
Discovery site Bergedorf Obs.
Discovery date 27 February 1973
Designations
MPC designation 1999 Hirayama
Named after
Kiyotsugu Hirayama
(astronomer)[2]
1973 DR · 1935 GF
1940 EH · 1951 EY1
1951 FA · 1965 UF
1969 NB · 1975 NE
main-belt · (outer)[3]
Orbital characteristics[1]
Epoch 13 January 2016 (JD 2457400.5)
Uncertainty parameter 0
Observation arc 75.96 yr (27745 days)
Aphelion 3.4706 AU (519.19 Gm)
Perihelion 2.7579 AU (412.58 Gm)
3.1143 AU (465.89 Gm)
Eccentricity 0.11442
5.50 yr (2007.4 d)
291.94°
0° 10m 45.624s / day
Inclination 12.534°
148.05°
356.88°
Earth MOID 1.7702 AU (264.82 Gm)
Jupiter MOID 1.54473 AU (231.088 Gm)
Jupiter Tisserand parameter 3.171
Physical characteristics
Dimensions 33.95 km[4]
35.68±0.55 km[5]
38.28±0.40 km[6]
33.81 km (derived)[3]
Mean radius
16.975 ± 1.05 km
Mass 4.1×1016 kg[citation needed]
15.63 h (0.651 d)[1][7]
22.37±0.03 h[8]
13.5921±0.0003 h[a]
0.0882 ± 0.012[1][4]
0.082±0.003[5]
0.053±0.005[6]
0.0675 (derived)[3]
C[3]
11.0[1]
10.6[7]

1999 Hirayama, provisional designation 1973 DR, is a carbonaceous asteroid from the outer region of the asteroid belt, about 34 kilometers in diameter. It was discovered by Czech astronomer Luboš Kohoutek at the Hamburger Bergedorf Observatory, Germany, on 27 February 1973.[9]

The C-type asteroid orbits the Sun at a distance of 2.8–3.5 AU once every five and a half years (2,008 days). Its orbit shows an eccentricity of 0.11 and is tilted by 13 degrees to the plane of the ecliptic. According to the surveys carried out by the space-based IRAS, Akari and WISE satellites and the subsequent NEOWISE mission, the body's surface has an albedo in the range of 0.05–0.09.[4][5][6]

The light curve analysis showed a periodicity of 15.63±0.01 hours, during which time the brightness of the object varies by 0.45±0.04 in magnitude.[7] The spectrum of this object matches a C-type Tholen classification, but with a "broad absorption band that can be associated to a process of aqueous alteration".[10] That is, the surface appears to show some form of water modification. A more recent observations rendered a somewhat shorter period of 13.6 hours.[a]

The minor planet is named in honour of Japanese astronomer Kiyotsugu Hirayama (1874–1943), best known for his discovery that many asteroid orbits were more similar to one another than chance would allow, leading to the concept of asteroid families, now called Hirayama families. The lunar carter Hirayama is also named in his honour.[2]

References[edit]

  1. ^ a b Hamanowa (2011) web: rotation period 13.5921±0.0003 hours with a brightness amplitude of 0.57 mag. Summary figures at Collaborative Asteroid Lightcurve Link (CALL) for (1999) Hirayama
  1. ^ a b c d e "JPL Small-Body Database Browser: 1999 Hirayama (1973 DR)" (2015-11-20 last obs.). Jet Propulsion Laboratory. Retrieved 17 April 2016. 
  2. ^ a b Schmadel, Lutz D. (2003). Dictionary of Minor Planet Names – (1999) Hirayama. Springer Berlin Heidelberg. p. 162. ISBN 978-3-540-29925-7. Retrieved October 2015. 
  3. ^ a b c d "LCDB Data for (1999) Hirayama". Asteroid Lightcurve Database (LCDB). Retrieved December 2015. 
  4. ^ a b c Tedesco, E. F.; Noah, P. V.; Noah, M.; Price, S. D. (October 2004). "IRAS Minor Planet Survey V6.0". NASA Planetary Data System. Bibcode:2004PDSS...12.....T. Retrieved December 2015. 
  5. ^ a b c Usui, Fumihiko; Kuroda, Daisuke; Müller, Thomas G.; Hasegawa, Sunao; Ishiguro, Masateru; Ootsubo, Takafumi; et al. (October 2011). "Asteroid Catalog Using Akari: AKARI/IRC Mid-Infrared Asteroid Survey". Publications of the Astronomical Society of Japan 63 (5): 1117–1138. Bibcode:2011PASJ...63.1117U. doi:10.1093/pasj/63.5.1117. Retrieved December 2015. 
  6. ^ a b c Masiero, Joseph R.; Mainzer, A. K.; Grav, T.; Bauer, J. M.; Cutri, R. M.; Nugent, C.; Cabrera, M. S. (November 2012). "Preliminary Analysis of WISE/NEOWISE 3-Band Cryogenic and Post-cryogenic Observations of Main Belt Asteroids". The Astrophysical Journal Letters 759 (1): 5. arXiv:1209.5794. Bibcode:2012ApJ...759L...8M. doi:10.1088/2041-8205/759/1/L8. Retrieved December 2015. 
  7. ^ a b c Menke, John; Cooney, Walt; Gross, John; Terrell, Dirk; Higgins, David (October 2008). "Asteroid Lightcurve Analysis at Menke Observatory". The Minor Planet Bulletin 35 (4): 155–160. Bibcode:2008MPBu...35..155M. ISSN 1052-8091. Retrieved December 2015. 
  8. ^ Behrend, Raoul. "Asteroids and comets rotation curves – (1999) Hirayama". Geneva Observatory. Retrieved December 2015. 
  9. ^ "1999 Hirayama (1973 DR)". Minor Planet Center. Retrieved October 2015. 
  10. ^ Lazzaro, D.; et al. (November 2004), "S3OS2: the visible spectroscopic survey of 820 asteroids", Icarus 172 (1): 179–220, Bibcode:2004Icar..172..179L, doi:10.1016/j.icarus.2004.06.006. 

External links[edit]