786 Bredichina

786 Bredichina (prov. designation: A914 HD or 1914 UO) is a carbonaceous and very large background asteroid, approximately 104 kilometers (65 miles) in diameter, located in the outer region of the asteroid belt. It was discovered by German astronomer Franz Kaiser at the Heidelberg-Königstuhl State Observatory on 20 April 1914.[1] The elongated C-type asteroid has a longer than average rotation period of 29.4 hours. It was named after Russian astronomer Fyodor Bredikhin (1831–1904).[2]

786 Bredichina
Discovery [1]
Discovered byF. Kaiser
Discovery siteHeidelberg Obs.
Discovery date20 April 1914
Designations
(786) Bredichina
Named after
A914 HD · 1914 UO
Orbital characteristics [3]
Epoch 31 May 2020 (JD 2459000.5)
Uncertainty parameter 0
Observation arc105.79 yr (38,638 d)
Aphelion3.6852 AU
Perihelion2.6690 AU
3.1771 AU
Eccentricity0.1599
5.66 yr (2,068 d)
267.56°
0° 10m 26.4s / day
Inclination14.518°
89.766°
133.61°
Physical characteristics
Dimensions160.5 km × 80.6 km[5]
Mean diameter
  • 91.60±6.2 km[7]
  • 98.34±6.00 km[8]
  • 108.309±0.868 km[9]
  • 111.47±1.30 km[10]
Mass(2.82±2.79)×1018 kg[8]
29.434±0.001 h[11]

    Orbit and classification

    Bredichina is a non-family asteroid of the main belt's background population when applying the hierarchical clustering method to its proper orbital elements.[4][5][6] It orbits the Sun in the outer main-belt at a distance of 2.7–3.7 AU once every 5 years and 8 months (2,068 days; semi-major axis of 3.18 AU). Its orbit has an eccentricity of 0.16 and an inclination of 15° with respect to the ecliptic.[3] The body's observation arc begins at Heidelberg Observatory on 21 April 1914, the night after its official discovery observation.[1]

    Naming

    This minor planet was named after Fyodor Bredikhin (1831–1904), also known as Theodor or Feodor Alexandrovich Bredichin, a Russian astronomer and director of the Pulkovo Observatory. He has made important contributions to the study of comets. The naming was also mentioned in The Names of the Minor Planets by Paul Herget in 1955 (H 78).[2] The lunar crater Bredikhin is also named after him.[13]

    Physical characteristics

    In the Tholen classification, Bredichina is a common, carbonaceous C-type asteroid.[3] It is also a C-type and C0-type in the Tedesco and Barucci classification from the 1908s.[5]

    Rotation period

    In March 2015, a rotational lightcurve of Bredichina was obtained from photometric observations by Spanish astronomers Alfonso Carreño (J08), Amadeo Aznar (Z95), Enrique Arce (J67), Pedro Brines (Z98), and Juan Lozano (I57). Lightcurve analysis gave a rotation period of 29.434±0.001 hours with a brightness variation of 0.51±0.02 magnitude (U=3−).[11]

    Previously, in August 2008, Argentine astronomer Ricardo Gil-Hutton derived period of 18.61±0.02 hours with an amplitude of 0.60±0.03 magnitude (U=2).[14] Tentative measurements were also made by Italian Nicola Cornero and Federico Manzini at the Sozzago Astronomical Station (A12) in May 2010, which gave a period of 27.88 hours with an amplitude of 0.049 magnitude (U=2−).[15] The same period was also determined by Eric Barbotin in February 2020, though with a higher brightness variation of 0.51±0.24.[15]

    Diameter and albedo

    According to the surveys carried out by the Infrared Astronomical Satellite IRAS, the NEOWISE mission of NASA's Wide-field Infrared Survey Explorer (WISE), and the Japanese Akari satellite, Bredichina measures (91.60±6.2), (108.309±0.868) and (111.47±1.30) kilometers in diameter and its surface has an albedo of (0.0730±0.011), (0.052±0.008) and (0.051±0.001), respectively.[7][9][10] The Collaborative Asteroid Lightcurve Link adopts the results obtained by IRAS, that is, an albedo of 0.0730 and a diameter of 91.60 kilometers based on an absolute magnitude of 8.65,[12] while Carry give a diameter of 98.34±6.00 km and estimates a mass of (2.82±2.79)×1018 kilogramm.[8] Alternative mean-diameter measurements published by the WISE team include (84.50±26.02 km), (93.62±31.89 km), (98.719±1.004 km), (127.664±58.629 km) and (130.149±43.55 km) with corresponding albedos of (0.04±0.03), (0.05±0.09), (0.0628±0.0021), (0.028±0.014) and (0.0347±0.0308).[5][12]

    On 10 January 2015, an asteroid occultation of Bredichina gave a best-fit ellipse dimension of (160.5 km × 80.6 km), indicative of a highly elongated shape, with a good quality rating of 3. These timed observations are taken when the asteroid passes in front of a distant star.[5]

    References
    1. "786 Bredichina (A914 HD)". Minor Planet Center. Retrieved 30 March 2020.
    2. Schmadel, Lutz D. (2007). "(786) Bredichina". Dictionary of Minor Planet Names. Springer Berlin Heidelberg. p. 74. doi:10.1007/978-3-540-29925-7_787. ISBN 978-3-540-00238-3.
    3. "JPL Small-Body Database Browser: 786 Bredichina (A914 HD)" (2020-02-02 last obs.). Jet Propulsion Laboratory. Retrieved 30 March 2020.
    4. "Asteroid 786 Bredichina – Proper Elements". AstDyS-2, Asteroids – Dynamic Site. Retrieved 30 March 2020.
    5. "Asteroid 786 Bredichina". Small Bodies Data Ferret. Retrieved 30 March 2020.
    6. Zappalà, V.; Bendjoya, Ph.; Cellino, A.; Farinella, P.; Froeschle, C. (1997). "Asteroid Dynamical Families". NASA Planetary Data System: EAR-A-5-DDR-FAMILY-V4.1. Retrieved 30 March 2020.} (PDS main page)
    7. Tedesco, E. F.; Noah, P. V.; Noah, M.; Price, S. D. (October 2004). "IRAS Minor Planet Survey V6.0". NASA Planetary Data System. 12: IRAS-A-FPA-3-RDR-IMPS-V6.0. Bibcode:2004PDSS...12.....T. Retrieved 30 March 2020.
    8. Carry, B. (December 2012), "Density of asteroids", Planetary and Space Science, 73, pp. 98–118, arXiv:1203.4336, Bibcode:2012P&SS...73...98C, doi:10.1016/j.pss.2012.03.009 See Table 1.
    9. Mainzer, A. K.; Bauer, J. M.; Cutri, R. M.; Grav, T.; Kramer, E. A.; Masiero, J. R.; et al. (June 2016). "NEOWISE Diameters and Albedos V1.0". NASA Planetary Data System. Bibcode:2016PDSS..247.....M. Retrieved 30 March 2020.
    10. 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 30 March 2020. (online, AcuA catalog p. 153)
    11. Garceràn, Alfonso Carreño; Macias, Amadeo Aznar; Mansego, Enrique Arce; Rodriguez, Pedro Brines; de Haro, Juan Lozano (October 2015). "Lightcurve Analysis of Six Asteroids" (PDF). Minor Planet Bulletin. 42 (4): 235–237. Bibcode:2015MPBu...42..235G. ISSN 1052-8091. Retrieved 30 March 2020.
    12. "LCDB Data for (786) Bredichina". Asteroid Lightcurve Database (LCDB). Retrieved 30 March 2020.
    13. "Lunar crater Bredikhin". Gazetteer of Planetary Nomenclature. USGS Astrogeology Research Program.
    14. Gil-Hutton, R.; Cañada, M. (April 2003). "Photometry of Fourteen Main Belt Asteroids". Revista Mexicana de Astronomía y Astrofísica. 39: 69–76. Bibcode:2003RMxAA..39...69G. ISSN 0185-1101.
    15. Behrend, Raoul. "Asteroids and comets rotation curves – (786) Bredichina". Geneva Observatory. Retrieved 30 March 2020.
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