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1187 Afra - Wikipedia

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1187 Afra
Discovery^[1]
Modelled shape of Afra from its lightcurve
Discovered by	K. Reinmuth
Discovery site	Heidelberg Obs.
Discovery date	6 December 1929
Designations
MPC designation	(1187) Afra
Named after	unknown^[2]
Alternative designations	1929 XC
Minor planet category	main-belt^[1]^[3] · (middle) background^[4]^[5]
Orbital characteristics^[3]
Epoch 31 May 2020 (JD 2459000.5)
Uncertainty parameter 0
Observation arc	90.16 yr (32,932 d)
Aphelion	3.2285 AU
Perihelion	2.0523 AU
Semi-major axis	2.6404 AU
Eccentricity	0.2227
Orbital period (sidereal)	4.29 yr (1,567 d)
Mean anomaly	52.040°
Mean motion	0° 13^m 46.92^s / day
Inclination	10.697°
Longitude of ascending node	327.16°
Argument of perihelion	74.956°
Physical characteristics
Mean diameter	31.83±3.9 km^[6] 31.96±0.33 km^[7] 32.348±0.299 km^[8]
Synodic rotation period	14.06993±0.00001 h^[9] 14.0701±0.0005 h^[10] 14.09±0.02 h^[11] 14.645±0.006 h^[12]
Geometric albedo	0.051±0.007^[8] 0.0527^[6] 0.053^[7]
Spectral type	SMASS = X^[3]
Absolute magnitude (H)	11.50^[1]^[3]

1187 Afra (prov. designation: 1929 XC) is a dark background asteroid from the central regions of the asteroid belt. It was discovered by German astronomer Karl Reinmuth at Heidelberg Observatory on 6 December 1929.^[1] The X-type asteroid has a rotation period of 14.1 hours and measures approximately 32 kilometers (20 miles) in diameter. The origin of the asteroid's name remains unknown.

Orbit and classification

Afra 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 central asteroid belt at a distance of 2.1–3.2 AU once every 4 years and 3 months (1,567 days; semi-major axis of 2.64 AU). Its orbit has an eccentricity of 0.22 and an inclination of 11° with respect to the ecliptic.^[3] The body's observation arc begins at Heidelberg in January 1930, seven weeks after its official discovery observation.^[1]

Naming

It is not known to what person, group of persons, or occurrence the name "Afra" refers to.^[2]

Unknown meaning

Among the many thousands of named minor planets, Afra is one of 120 asteroids, for which no official naming citation has been published. All of these low-numbered asteroids have numbers between 164 Eva and 1514 Ricouxa and were discovered between 1876 and the 1930s, predominantly by astronomers Auguste Charlois, Johann Palisa, Max Wolf and Karl Reinmuth.^[13]

Physical characteristics

The lightcurve of Afra shows a periodicity of 14.09±0.02 hours, during which time the brightness of the object varies by 0.40±0.02 in magnitude.^[11]^[14]

References

^ ^a ^b ^c ^d ^e "1187 Afra (1929 XC)". Minor Planet Center. Retrieved 14 March 2020.
^ ^a ^b Schmadel, Lutz D. (2007). "(1187) Afra". Dictionary of Minor Planet Names. Springer Berlin Heidelberg. p. 100. doi:10.1007/978-3-540-29925-7_1188. ISBN 978-3-540-00238-3.
^ ^a ^b ^c ^d ^e "JPL Small-Body Database Browser: 1187 Afra (1929 XC)" (2020-02-04 last obs.). Jet Propulsion Laboratory. Archived from the original on 18 September 2020. Retrieved 14 March 2020.
^ ^a ^b "Asteroid 1187 Afra – Proper Elements". AstDyS-2, Asteroids – Dynamic Site. Retrieved 14 March 2020.
^ ^a ^b "Asteroid 1187 Afra". Small Bodies Data Ferret. Retrieved 14 March 2020.
^ ^a ^b 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 14 March 2020.
^ ^a ^b 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. (online, AcuA catalog p. 153)
^ ^a ^b 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 14 March 2020.
^ Ďurech, J.; Hanuš, J.; Oszkiewicz, D.; Vančo, R. (March 2016). "Asteroid models from the Lowell photometric database". Astronomy and Astrophysics. 587: A48. arXiv:1601.02909. Bibcode:2016A&A...587A..48D. doi:10.1051/0004-6361/201527573. ISSN 0004-6361.
^ Behrend, Raoul. "Asteroids and comets rotation curves – (1187) Afra". Geneva Observatory. Retrieved 14 March 2020.
^ ^a ^b Menke, John; Cooney, Walt; Gross, John; Terrell, Dirk; Higgins, David (October 2008). "Asteroid Lightcurve Analysis at Menke Observatory" (PDF). Minor Planet Bulletin. 35 (4): 155–160. Bibcode:2008MPBu...35..155M. ISSN 1052-8091.
^ Clark, Maurice (July 2019). "Asteroid Photometry from the Preston Gott Observatory" (PDF). Minor Planet Bulletin. 46 (3): 346–349. Bibcode:2019MPBu...46..346C. ISSN 1052-8091.
^ Schmadel, Lutz D. (2007). "Appendix 11 – Minor Planet Names with Unknown Meaning". Dictionary of Minor Planet Names – Fifth Revised and Enlarged revision. Springer Berlin Heidelberg. pp. 927–929. ISBN 978-3-540-00238-3.
^ "LCDB Data for (1187) Afra". Asteroid Lightcurve Database (LCDB). Retrieved 14 March 2020.

External links

Lightcurve Database Query (LCDB), at www.minorplanet.info
Dictionary of Minor Planet Names, Google books
Asteroids and comets rotation curves, CdR – Geneva Observatory, Raoul Behrend
Discovery Circumstances: Numbered Minor Planets (1)-(5000) – Minor Planet Center
1187 Afra at AstDyS-2, Asteroids—Dynamic Site
- Ephemeris · Observation prediction · Orbital info · Proper elements · Observational info
1187 Afra at the JPL Small-Body Database
- Close approach · Discovery · Ephemeris · Orbit viewer · Orbit parameters · Physical parameters

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