Astronomy:850 Altona

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850 Altona
Discovered byS. Belyavskyj
Discovery siteSimeiz Obs.
Discovery date27 March 1916
(850) Altona
Named afterGerman city of Altona[2]
A916 FG · A923 RP
1916 Σ24 · 1923 RP
Minor planet categorymain-belt[1][3] · (outer)
Orbital characteristics[3]
Epoch 31 May 2020 (JD 2459000.5)
Uncertainty parameter 0
Observation arc102.52 yr (37,446 d)
|{{{apsis}}}|helion}}3.3753 AU
|{{{apsis}}}|helion}}2.6234 AU
2.9994 AU
Orbital period5.19 yr (1,897 d)
Mean anomaly318.70°
Mean motion0° 11m 22.92s / day
Longitude of ascending node121.13°
Physical characteristics
Dimensions80.0 km × 80.0 km[5]
Rotation period11.1913±0.0009 h[7][lower-alpha 1]
X (S3OS2)[8]
Absolute magnitude (H)9.70[1][3]

850 Altona (prov. designation: A916 FG or 1916 Σ24) is a large background asteroid, approximately 77 kilometers (48 miles) in diameter, that is located in the outer region of the asteroid belt. It was discovered on 27 March 1916, by Russian astronomer Sergey Belyavsky at the Simeiz Observatory on the Crimean peninsula.[1] The X-type asteroid has a rotation period of 11.2 hours. It was named after the city of Altona near Hamburg, Germany.[2]

Orbit and classification

Altona 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 2.6–3.4 AU once every 5 years and 2 months (1,897 days; semi-major axis of 3 AU). Its orbit has an eccentricity of 0.13 and an inclination of 16° with respect to the ecliptic.[3] The body's observation arc begins at Algiers Observatory in North Africa on 28 July 1917, more than a year after its official its discovery observation at the Simeiz Observatory on 27 March 1916.[1]


This minor planet was named after Altona, Hamburg, the location of the Altona Observatory, at which Heinrich Christian Schumacher began publication of the astronomical journal Astronomische Nachrichten in 1821. Altona is the home-town of Friedrich Georg Wilhelm von Struve, who founded the Pulkovo Observatory near St Petersburg, Russia. The naming was also mentioned in The Names of the Minor Planets by Paul Herget in 1955 (H 83).[2]

Physical characteristics

In both the Tholen- and SMASS-like taxonomy of the Small Solar System Objects Spectroscopic Survey (S3OS2), Altona is an X-type asteroid.[5][8]

Rotation period

In September 2017, a rotational lightcurve of Altona was obtained from photometric observations by Brian Warner at his Palmer Divide Station (U82) of the Center for Solar System Studies in California. Lightcurve analysis gave a welll-defined rotation period of 11.1913±0.0009 hours with a brightness variation of 0.17±0.01 magnitude ({{{1}}}).[7][lower-alpha 1]

The result supersedes previous period determinations of:[9] 11.131±0.0066 and 11.16±0.380 hours by astronomers at the Palomar Transient Factory, California, in January 2014 ({{{1}}}),[10][11] 11.195±0.001 hours by Michael Alkema at the Elephant Head Observatory (G35) in Arizona in December 2012 ({{{1}}}),[12] 11.197±0.002 hours by Frederick Pilcher at the Organ Mesa Observatory (G50) in June 2010 ({{{1}}}),[13] and 11.9±0.5 hours by Robin Esseiva, Nicolas Esseiva and Raoul Behrend in April 2015 ({{{1}}}).[14]

Diameter and albedo

According to the surveys carried out by the Japanese Akari satellite, the NEOWISE mission of NASA's Wide-field Infrared Survey Explorer (WISE), and the Infrared Astronomical Satellite IRAS, Altona measures (73.16±0.88), (77.097±2.263) and (80.90±1.8) kilometers in diameter and its surface has an albedo of (0.048±0.001), (0.043±0.009) and (0.0390±0.002), respectively.[15][16][17]

The Collaborative Asteroid Lightcurve Link derives an albedo of 0.0356 and a diameter of 80.85 kilometers based on an absolute magnitude of 9.7.[9] Alternative mean-diameter measurements published by the WISE team include (59.945±0.585 km), (63.25±16.39 km), (69.47±2.17 km) and (81.518±19.16 km) with corresponding albedos of (0.0710±0.0051), (0.06±0.04), (0.053±0.018), and (0.0403±0.0278).[5][9] An asteroid occultation observed on 3 April 2008, gave a best-fit ellipse dimension of (80.0 km × 80.0 km). These timed observations are taken when the asteroid passes in front of a distant star.[5]


  1. 1.0 1.1 Lightcurve plot of (850) Altona by Brian Warner, Palmer Divide Station (U82) at Center for Solar System Studies (2017). Rotation period 11.1913±0.0009 hours with a brightness amplitude of 0.17±0.01 mag. Quality code is 3. Summary figures at the LCDB and CS3.


  1. 1.0 1.1 1.2 1.3 1.4 "850 Altona (A916 FG)". Minor Planet Center. 
  2. 2.0 2.1 2.2 Schmadel, Lutz D. (2007). "(850) Altona". Dictionary of Minor Planet Names. Springer Berlin Heidelberg. p. 78. doi:10.1007/978-3-540-29925-7_851. ISBN 978-3-540-00238-3. 
  3. 3.0 3.1 3.2 3.3 "JPL Small-Body Database Browser: 850 Altona (A916 FG)". Jet Propulsion Laboratory. 
  4. 4.0 4.1 "Asteroid 850 Altona – Proper Elements". AstDyS-2, Asteroids – Dynamic Site. 
  5. 5.0 5.1 5.2 5.3 5.4 5.5 "Asteroid 850 Altona". Small Bodies Data Ferret. 
  6. Noah Webster (1884) A Practical Dictionary of the English Language
  7. 7.0 7.1 Warner, Brian D. (January 2018). "Asteroid Lightcurve Analysis at CS3-Palmer Divide Station: 2017 July Through October". Minor Planet Bulletin 45 (1): 39–45. ISSN 1052-8091. Bibcode2018MPBu...45...39W. 
  8. 8.0 8.1 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". Icarus 172 (1): 179–220. doi:10.1016/j.icarus.2004.06.006. Bibcode2004Icar..172..179L. Retrieved 6 March 2020. 
  9. 9.0 9.1 9.2 "LCDB Data for (850) Altona". Asteroid Lightcurve Database (LCDB). 
  10. Waszczak, Adam; Chang, Chan-Kao; Ofek, Eran O.; Laher, Russ; Masci, Frank; Levitan, David et al. (September 2015). "Asteroid Light Curves from the Palomar Transient Factory Survey: Rotation Periods and Phase Functions from Sparse Photometry". The Astronomical Journal 150 (3): 35. doi:10.1088/0004-6256/150/3/75. Bibcode2015AJ....150...75W. 
  11. Chang, Chan-Kao (August 2015). "Asteroid Spin-rate Study Using the Intermediate Palomar Transient Factory". The Astrophysical Journal Supplement Series 219 (2): 27. doi:10.1088/0067-0049/219/2/27. ISSN 0067-0049. Bibcode2015ApJS..219...27C. 
  12. Alkema, Michael S. (July 2013). "Asteroid Lightcurve Analysis at Elephant Head Observatory: 2012 November - 2013 April". Minor Planet Bulletin 40 (3): 133–137. ISSN 1052-8091. Bibcode2013MPBu...40..133A. 
  13. Pilcher, Frederick; Benishek, Vladimir (January 2011). "Rotation Period Determinations for 266 Aline and 850 Altona". Minor Planet Bulletin 38 (1): 15–16. ISSN 1052-8091. Bibcode2011MPBu...38...15P. 
  14. Behrend, Raoul. "Asteroids and comets rotation curves – (850) Altona". Geneva Observatory. 
  15. 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. doi:10.1093/pasj/63.5.1117. Bibcode2011PASJ...63.1117U.  (online, AcuA catalog p. 153)
  16. 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. Bibcode2016PDSS..247.....M. Retrieved 6 March 2020. 
  17. 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. Bibcode2004PDSS...12.....T. Retrieved 6 March 2020. 

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