1242 Zambesia

1242 Zambesia

Discovery[1]
Discovered by	C. Jackson
Discovery site	Johannesburg Obs.
Discovery date	28 April 1932
Designations
MPC designation	(1242) Zambesia
Named after	Zambezi basin[2] (southern Africa)
Alternative designations	1932 HL · 1947 TE 1948 AC · 1967 EF A908 BF
Minor planet category	main-belt · (middle) background[3]
Orbital characteristics[1]
Epoch 4 September 2017 (JD 2458000.5)
Uncertainty parameter 0
Observation arc	109.42 yr (39,966 days)
Aphelion	3.2569 AU
Perihelion	2.2201 AU
Semi-major axis	2.7385 AU
Eccentricity	0.1893
Orbital period (sidereal)	4.53 yr (1,655 days)
Mean anomaly	139.42°
Mean motion	0° 13^m 3^s / day
Inclination	10.163°
Longitude of ascending node	350.01°
Argument of perihelion	52.968°
Physical characteristics
Dimensions	42.16±11.24 km[4] 47.54 km (derived)[5] 47.594±0.347 km[6] 47.70±1.6 km[7] 52.668±0.952 km[8] 53.70±3.05 km[9] 62.23±0.79 km[10] 72.818±22.99 km[11]
Synodic rotation period	15.72±0.14 h[a] 17.305 h[b] >24 h (poor)[12]
Geometric albedo	0.0252±0.0184[11] 0.04±0.01[9] 0.043±0.001[10] 0.045±0.032[4] 0.0541 (derived)[5] 0.058±0.010[6] 0.0581±0.0040[8] 0.0708±0.005[7]
Spectral type	C (S3OS2)[13]
Absolute magnitude (H)	10.10[7][8][10] · 10.40[1][5][11] · 10.41[9] · 10.87[4]

1242 Zambesia (prov. designation: 1932 HL) is a dark background asteroid from the central regions of the asteroid belt, approximately 48 kilometers (30 miles) in diameter. It was discovered on 28 April 1932, by South African astronomer Cyril Jackson at the Union Observatory in Johannesburg.[14] The asteroid was named for the large Zambezi basin in southern Africa.[2]

Orbit and classification

Zambesia is a non-family asteroid from the main belt's background population.[3] It orbits the Sun in the central main-belt at a distance of 2.2–3.3 AU once every 4 years and 6 months (1,655 days; semi-major axis of 2.74 AU). Its orbit has an eccentricity of 0.19 and an inclination of 10° with respect to the ecliptic.[1]

The asteroid was first observed as A908 BF at Taunton Observatory (803) in January 1908. The body's observation arc begins at the United States Naval Observatory (786) in February 1908, more than 26 years prior to its official discovery observation at Johannesburg.[14]

Naming

This minor planet was named after the Zambezi river valley, partially part of the former British Central Africa Protectorate. The official naming citation was mentioned in The Names of the Minor Planets by Paul Herget in 1955 (H 114).[2] The large Zambezi basin stretches across modern Angola, Botswana, Mozambique, Namibia, Zambia and Zimbabwe.

Physical characteristics

In both the Tholen- and SMASS-like taxonomy of the Small Solar System Objects Spectroscopic Survey (S3OS2), Zambesia is a common, carbonaceous C-type asteroid.[13]

Rotation period

In October 2015, a rotational lightcurve of Zambesia was obtained by a group of Spanish astronomers. Lightcurve analysis gave a rotation period of 15.72 hours with a brightness variation of 0.15 magnitude (U=2).[a] Previous photometric observations gave a divergent period of 17.305 and 24+ hours (U=1/2).[12][b]

Diameter and albedo

According to the surveys carried out by the Infrared Astronomical Satellite IRAS, the Japanese Akari satellite and the NEOWISE mission of NASA's Wide-field Infrared Survey Explorer, Zambesia measures between 42.16 and 72.818 kilometers in diameter and its surface has an albedo between 0.0252 and 0.0708.[4][6][7][8][9][10][11]

The Collaborative Asteroid Lightcurve Link derives an albedo of 0.0541 and a diameter of 47.54 kilometers based on an absolute magnitude of 10.4.[5]

Notes

1. Aznar, A.; Garceran, A.C.; Mansego, E.A.; Rodriguez, P.B.; et al. (2016) Minor Planet Bul. 43, 174-181.; rotation period 15.72±0.14 hours with a brightness amplitude of 0.15±0.01 mag. Quality code of 2. Summary figures at the LCDB.
2. Anonymous lightcurve (2011) for (1242) Zambesia: rotation period 17.305 hours with a brightness amplitude of 0.24 mag. Quality code of 2. Summary figures at the LCDB.

References

1. "JPL Small-Body Database Browser: 1242 Zambesia (1932 HL)" (2017-07-05 last obs.). Jet Propulsion Laboratory. Retrieved 4 January 2018.
2. Schmadel, Lutz D. (2003). "(1242) Zambesia". Dictionary of Minor Planet Names – (1242) Zambesia. Springer Berlin Heidelberg. p. 103. doi:10.1007/978-3-540-29925-7_1243. ISBN 978-3-540-00238-3.
3. "Asteroid 1242 Zambesia – Proper Elements". AstDyS-2, Asteroids – Dynamic Site. Retrieved 29 October 2019.
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:1209.5794. Bibcode:2012ApJ...759L...8M. doi:10.1088/2041-8205/759/1/L8. S2CID 46350317. Retrieved 4 January 2018.
5. "LCDB Data for (1242) Zambesia". Asteroid Lightcurve Database (LCDB). Retrieved 4 January 2018.
6. Masiero, Joseph R.; Grav, T.; Mainzer, A. K.; Nugent, C. R.; Bauer, J. M.; Stevenson, R.; et al. (August 2014). "Main-belt Asteroids with WISE/NEOWISE: Near-infrared Albedos". The Astrophysical Journal. 791 (2): 11. arXiv:1406.6645. Bibcode:2014ApJ...791..121M. doi:10.1088/0004-637X/791/2/121. S2CID 119293330.
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 22 October 2019.
8. 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:1109.6407. Bibcode:2011ApJ...741...90M. doi:10.1088/0004-637X/741/2/90. S2CID 35447010.
9. Nugent, C. R.; Mainzer, A.; Bauer, J.; Cutri, R. M.; Kramer, E. A.; Grav, T.; et al. (September 2016). "NEOWISE Reactivation Mission Year Two: Asteroid Diameters and Albedos". The Astronomical Journal. 152 (3): 12. arXiv:1606.08923. Bibcode:2016AJ....152...63N. doi:10.3847/0004-6256/152/3/63.
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. (online, AcuA catalog p. 153)
11. Masiero, Joseph R.; Nugent, C.; Mainzer, A. K.; Wright, E. L.; Bauer, J. M.; Cutri, R. M.; et al. (October 2017). "NEOWISE Reactivation Mission Year Three: Asteroid Diameters and Albedos". The Astronomical Journal. 154 (4): 10. arXiv:1708.09504. Bibcode:2017AJ....154..168M. doi:10.3847/1538-3881/aa89ec.
12. Behrend, Raoul. "Asteroids and comets rotation curves – (1242) Zambesia". Geneva Observatory. Retrieved 4 January 2018.
13. 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 10 February 2020.
14. "1242 Zambesia (1932 HL)". Minor Planet Center. Retrieved 4 January 2018.

External links

• Dictionary of Minor Planet Names, Google books
• Asteroids and comets rotation curves, CdR – Observatoire de Genève, Raoul Behrend
• Discovery Circumstances: Numbered Minor Planets (1)-(5000) – Minor Planet Center
• 1242 Zambesia at AstDyS-2, Asteroids—Dynamic Site
  • Ephemeris · Observation prediction · Orbital info · Proper elements · Observational info
• 1242 Zambesia at the JPL Small-Body Database
  • Close approach · Discovery · Ephemeris · Orbit viewer · Orbit parameters · Physical parameters