904 Rockefellia

904 Rockefellia (prov. designation: A918 UC or 1918 EO) is a dark and large background asteroid from the outer regions of the asteroid belt, that measures approximately 59 kilometers (37 miles) in diameter. It was discovered on 29 October 1918, by German astronomer Max Wolf at the Heidelberg-Königstuhl State Observatory.[1] The carbonaceous C-type asteroid (Ch) has a rotation period of 6.8 hours and is rather spherical in shape. It was named after American philanthropist and oil industrialist John D. Rockefeller (1839–1937).[2]

904 Rockefellia
Discovery [1]
Discovered byM. F. Wolf
Discovery siteHeidelberg Obs.
Discovery date29 October 1918
Designations
(904) Rockefellia
Named after
John D. Rockefeller [2]
(American business magnate)
A918 UC · 1949 UK
1961 AK · A913 UD
A916 KC · 1918 EO
1913 UD · 1916 KC
main-belt [1][3] · (outer)
background [4][5]
Orbital characteristics [3]
Epoch 31 May 2020 (JD 2459000.5)
Uncertainty parameter 0
Observation arc106.24 yr (38,805 d)
Aphelion3.2567 AU
Perihelion2.7366 AU
2.9967 AU
Eccentricity0.0868
5.19 yr (1,895 d)
178.00°
0° 11m 24s / day
Inclination15.147°
198.08°
251.78°
Physical characteristics
Mean diameter
  • 49.146±0.763 km[6]
  • 58.75±1.7 km[7]
  • 61.36±0.77 km[8]
6.826±0.004 h[9]
  • 0.051±0.002[8]
  • 0.055±0.009[6]
  • 0.0561±0.003[7]
10.4[1][3]

    Orbit and classification

    Rockefellia 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] It orbits the Sun in the outer asteroid belt at a distance of 2.7–3.3 AU once every 5 years and 2 months (1,895 days; semi-major axis of 3 AU). Its orbit has an eccentricity of 0.09 and an inclination of 15° with respect to the ecliptic.[3] The asteroid was first observed as A913 UD (1913 UD) at the Simeiz Observatory on 28 October 1913, and three nights later at Heidelberg Observatory as well. The body's observation arc begins at Heidelberg on 6 December 1918, or five weeks after its official discovery observation.[1]

    Naming

    This minor planet was named after John D. Rockefeller (1839–1937), an American philanthropist and oilman who founded the Rockefeller Foundation. The official naming citation was mentioned in The Names of the Minor Planets by Paul Herget in 1955 (H 87).[2]

    Physical characteristics

    In the Tholen- and SMASS-like taxonomy of the Small Solar System Objects Spectroscopic Survey (S3OS2), Rockefellia is a Caa and Ch type, respectively, both indicating that it is a hydrated, carbonaceous C-type asteroid.[5][10]

    Rotation period

    In December 2017, a rotational lightcurve of Rockefellia was obtained from photometric observations by Tom Polakis at the Command Module Observatory (V02) in Arizona. Lightcurve analysis gave a rotation period of 6.826±0.004 hours with a low brightness variation of 0.14±0.03 magnitude (U=2).[9] The result supersedes tentative period determinations by Pierre Antonini (2009), Stephane Fauvaud (2011) and René Roy (2014), which were of lower quality (U=1/2/1).[11][12][13]

    Diameter and albedo

    According to the survey carried out by the NEOWISE mission of NASA's Wide-field Infrared Survey Explorer (WISE), the Infrared Astronomical Satellite IRAS, and the Japanese Akari satellite, Rockefellia measures (49.146±0.763), (58.75±1.7) and (61.36±0.77) kilometers in diameter and its surface has an albedo of (0.055±0.009), (0.0561±0.003) and (0.051±0.002), respectively.[6][7][8] The Collaborative Asteroid Lightcurve Link derives an albedo of 0.0357 and calculates a diameter of 58.51 kilometers based on an absolute magnitude of 10.4.[11] Alternative mean-diameter measurements published by the WISE team include (48.96±16.97 km), (52.127±3.976 km), (54.859±14.983 km) and (55.321±19.554 km) with corresponding albedos of (0.05±0.05), (0.071±0.010) and (0.04±0.03) and (0.042±0.033).[5][11]

    On 13 May 2005, an asteroid occultation gave a best-fit ellipse dimension of 59.0 × 59.0 kilometers.[5] These timed observations are taken when the asteroid passes in front of a distant star. However the quality of the measurement is rated poorly. A second, lower rated observation on 23 February 2013, measured an ellipse of 61.0 × 61.0 kilometers.[5]

    References
    1. "904 Rockefellia (A918 UC)". Minor Planet Center. Retrieved 24 February 2020.
    2. Schmadel, Lutz D. (2007). "(904) Rockefellia". Dictionary of Minor Planet Names. Springer Berlin Heidelberg. p. 81. doi:10.1007/978-3-540-29925-7_905. ISBN 978-3-540-00238-3.
    3. "JPL Small-Body Database Browser: 904 Rockefellia (A918 UC)" (2020-01-28 last obs.). Jet Propulsion Laboratory. Retrieved 24 February 2020.
    4. "Asteroid 904 Rockefellia – Proper Elements". AstDyS-2, Asteroids – Dynamic Site. Retrieved 24 February 2020.
    5. "Asteroid 904 Rockefellia". Small Bodies Data Ferret. Retrieved 24 February 2020.
    6. 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:1209.5794. Bibcode:2012ApJ...759L...8M. doi:10.1088/2041-8205/759/1/L8.
    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 24 February 2020.
    8. 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 24 February 2020. (online, AcuA catalog p. 153)
    9. Polakis, Tom (April 2018). "Lightcurve Analysis for Eleven Main-belt Asteroids" (PDF). Minor Planet Bulletin. 45 (2): 199–203. Bibcode:2018MPBu...45..199P. ISSN 1052-8091.
    10. Lazzaro, D.; Angeli, C. A.; Carvano, J. M.; Mothé-Diniz, T.; Duffard, R.; Florczak, M. (November 2004). "S3OS2: the visible spectroscopic survey of 820 asteroids" (PDF). Icarus. 172 (1): 179–220. Bibcode:2004Icar..172..179L. doi:10.1016/j.icarus.2004.06.006. Retrieved 24 February 2020.
    11. "LCDB Data for (904) Rockefellia". Asteroid Lightcurve Database (LCDB). Retrieved 24 February 2020.
    12. Behrend, Raoul. "Asteroids and comets rotation curves – (904) Rockefellia". Geneva Observatory. Retrieved 24 February 2020.
    13. Fauvaud, Stephane; Fauvaud, Marcel (October 2013). "Photometry of Minor Planets. I. Rotation Periods from Lightcurve Analysis for Seven Main-belt Asteroids" (PDF). Minor Planet Bulletin. 40 (4): 224–229. Bibcode:2013MPBu...40..224F. ISSN 1052-8091.
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