4607 Seilandfarm

4607 Seilandfarm
Discovery [1]
Discovered by K. Endate
K. Watanabe
Discovery site Kitami Obs.
Discovery date 25 November 1987
Designations
MPC designation 4607 Seilandfarm
Named after
 Seilandfarm
(Japanese farm)[2]
1987 WR · 1951 CK1
1975 EO4
main-belt · (inner) [3]
Orbital characteristics [1]
Epoch 31 July 2016 (JD 2457600.5)
Uncertainty parameter 0
Observation arc 28.54 yr (10,424 days)
Aphelion 2.3084 AU
Perihelion 2.2193 AU
2.2639 AU
Eccentricity 0.0197
3.41 yr (1,244 days)
109.36°
0° 17m 21.84s / day
Inclination 2.2521°
250.50°
220.42°
Known satellites 1 [lower-alpha 1][4]
Physical characteristics
Dimensions 6.33±0.27 km[5]
7.13 km (calculated)[3]
7.389±0.115 km[6]
3.9681±0.0002 h[lower-alpha 2]
3.9683±0.0001 h[lower-alpha 2][4]
0.20 (assumed)[3]
0.2239±0.0142[6]
0.279±0.035[5]
SMASS = L [1] · L [3]
12.89±0.34[7]
12.9[6]
13.00[5]
13.1[1]
13.2[3]

    4607 Seilandfarm, provisional designation 1987 WR, is a rare-type binary[lower-alpha 1] asteroid from the inner regions of the asteroid belt, approximately 7 kilometers in diameter. It was discovered on 25 November 1987, by Japanese amateur astronomers Kin Endate and Kazuro Watanabe at Kitami Observatory on the Japanese island of Hokkaidō.[8]

    The reddish body is classified as a rare L-type asteroid on the SMASS taxonomic scheme. It orbits the Sun at a distance of 2.2–2.3 AU once every 3 years and 5 months (1,244 days). Its orbit has an eccentricity of 0.02 and an inclination of 2° with respect to the ecliptic.[1] The asteroid's observation arc begins with its discovery in 1987, as the first two observations at Abastuman, Georgia, and at Crimea–Nauchnij from 1954 and 1975, respectively, remain unused.[8]

    In February 2009 and September 2014, three rotational Light-curves were obtained from photometric observations by astronomers Donald P. Pray and Petr Pravec at the U.S. Carbuncle and the Czech Ondřejov Observatory, respectively. The light-curves rendered a well-defined rotation period of 3.9681±0.0002 and 3.9683±0.0001 hours with a corresponding brightness variation of 0.15 and 0.17 in magnitude, indicating that the asteroid's shape is nearly spheroidal (U=3/3/3).[lower-alpha 2][4] During the photometric observations in February 2009, the asteroid was discovered to be a binary system. Its asteroid moon has an orbital period of 31.6 hours. Based on mutual eclipse/occultation events, the satellite is thought to be at least 29% the size of Seilandfarm,[lower-alpha 1] which would translate into a diameter of about 2 kilometers or more.

    According to the survey carried out by NASA's Wide-field Infrared Survey Explorer with its NEOWISE mission, the asteroid measures 6.3 and 7.4 and kilometers in diameter, and its surface has a corresponding albedo of 0.22 and 0.28,[5][6] while the Collaborative Asteroid Lightcurve Link assumes a standard albedo for stony asteroids of 0.20 and calculates a diameter of 7.1 kilometers, in agreement with the results obtained by the space-based observations.[3]

    The minor planet was named for Seilandfarm, a 50-hectare dairy and cattle farm, located in a hilly terrain, near the Japanese city of Kitami and not far from the observatory where this minor planet was discovered (also see 3785 Kitami). The farm was established by Akio Seino in 1942, and is now operated by four members of the Seino family.[2] Naming citation was published on 14 July 1992 (M.P.C. 20521).[9]

    References

    1. 1 2 3 CBET No. 1716, 2009 March 11Central Bureau for Astronomical Telegrams for (4607) Seilandfarm:
      Photometric observations obtained during Jan. 17-Feb. 25 reveal that minor planet (4607) is a binary system with an orbital period of 31.63 +/- 0.02 hr. The primary shows a period of 3.9683 +/- 0.0001 hr, and it has a lightcurve amplitude of 0.15 mag, suggesting a nearly spheroidal shape. Mutual eclipse/occultation events indicate a lower limit on secondary-to- primary mean-diameter ratio of 0.29.Central Bureau for Astronomical Telegrams No. 1716
      Reported by: D. Pray, Carbuncle Observatory, W. Brookfield, MA, U.S.A.; P. Kusnirak and P. Pravec, Ondrejov Observatory; J. Gross, W. Cooney, and D. Terrell, Sonoita Research Observatory, Sonoita, AZ; and R. Durkee, Minneapolis, MN.
    2. 1 2 3 Pravec (2009) web: rotation period 3.9683±0.0001 hours with a brightness amplitude of 0.15 mag, as well as Pravec (2014) web: rotation period 3.9681±0.0002 hours with a brightness amplitude of 0.17 mag. Quality Code for both observations: U=3 (denotes a secure result within the precision given and no ambiguity). Summary figures at Collaborative Asteroid Lightcurve Link (CALL) for (4607) Seilandfarm
    1. 1 2 3 4 5 "JPL Small-Body Database Browser: 4607 Seilandfarm (1987 WR)" (2016-06-09 last obs.). Jet Propulsion Laboratory. Retrieved 3 August 2016.
    2. 1 2 Schmadel, Lutz D. (2007). Dictionary of Minor Planet Names – (4607) Seilandfarm. Springer Berlin Heidelberg. p. 396. ISBN 978-3-540-00238-3. Retrieved 3 August 2016.
    3. 1 2 3 4 5 6 "LCDB Data for (4607) Seilandfarm". Asteroid Lightcurve Database (LCDB). Retrieved 3 August 2016.
    4. 1 2 3 Pray, D.; Brookfield, W.; Kusnirak, P.; Pravec, P.; Gross, J.; Cooney, W.; et al. (March 2009). "(4607) Seilandfarm". Central Bureau Electronic Telegrams (1716). Bibcode:2009CBET.1716....1P. Retrieved 3 January 2016.
    5. 1 2 3 4 Masiero, Joseph R.; Mainzer, A. K.; Grav, T.; Bauer, J. M.; Cutri, R. M.; Nugent, C.; et al. (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:1209.5794Freely accessible. Bibcode:2012ApJ...759L...8M. doi:10.1088/2041-8205/759/1/L8. Retrieved 3 August 2016.
    6. 1 2 3 4 Mainzer, A.; Grav, T.; Masiero, J.; Hand, E.; Bauer, J.; Tholen, D.; et al. (November 2011). "NEOWISE Studies of Spectrophotometrically Classified Asteroids: Preliminary Results". The Astrophysical Journal. 741 (2): 25. arXiv:1109.6407Freely accessible. Bibcode:2011ApJ...741...90M. doi:10.1088/0004-637X/741/2/90. Retrieved 3 August 2016.
    7. ↑ 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 3 August 2016.
    8. 1 2 "4607 Seilandfarm (1987 WR)". Minor Planet Center. Retrieved 3 August 2016.
    9. ↑ "MPC/MPO/MPS Archive". Minor Planet Center. Retrieved 3 August 2016.

    External links

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