Astronomy:1397 Umtata

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1397 Umtata
Discovery[1]
Discovered byC. Jackson
Discovery siteJohannesburg Obs.
Discovery date9 August 1936
Designations
(1397) Umtata
Named afterMthatha[2]
(South-African town)
1936 PG · 1931 GK
1945 QF · 1945 RC
1948 EB1
Minor planet categorymain-belt · (middle)[3]
background[4]
Orbital characteristics[1]
Epoch 4 September 2017 (JD 2458000.5)
Uncertainty parameter 0
Observation arc81.14 yr (29,638 days)
|{{{apsis}}}|helion}}3.3646 AU
|{{{apsis}}}|helion}}1.9967 AU
2.6806 AU
Eccentricity0.2551
Orbital period4.39 yr (1,603 days)
Mean anomaly173.37°
Mean motion0° 13m 28.56s / day
Inclination3.5109°
Longitude of ascending node77.437°
206.53°
Physical characteristics
Dimensions20.35±0.30 km[5]
20.40 km (derived)[3]
20.798±0.292 km[6]
22.895±0.285 km[7]
Rotation period30 h[8]
Geometric albedo0.0794±0.0140[7]
0.084±0.046[6]
0.10 (assumed)[3]
0.112±0.004[5]
S/C[3]
B–V = 0.690[1]
U–B = 0.210[1]
Absolute magnitude (H)11.47[1][5] · 11.57[3][7][8]


1397 Umtata, provisional designation 1936 PG, is an asteroid from the background population of the asteroid belt's central region, approximately 21 kilometers in diameter. It was discovered by South-African astronomer Cyril Jackson at the Union Observatory in Johannesburg on 9 August 1936.[9] The asteroid was named after the South-African town of Mthatha, formerly known as Umtata.[2]

Orbit and classification

Umtata is a non-family asteroid of the main belt's background population.[4] It orbits the Sun in the central asteroid belt at a distance of 2.0–3.4 AU once every 4 years and 5 months (1,603 days). Its orbit has an eccentricity of 0.26 and an inclination of 4° with respect to the ecliptic.[1]

The asteroid was first identified as 1931 GK at the Lowell Observatory in April 1931. The body's observation arc begins with its official discovery observation at Johannesburg.[9]

Physical characteristics

The asteroid's spectral type is unknown. The Lightcurve Data Base assumes an S- or C-type to be equally likely, using an average albedo of 0.10 (see below).[3][lower-alpha 1]

Rotation period

In May 1984, a rotational lightcurve of Umtata was obtained from photometric observations by American astronomer Richard Binzel. Analysis of the fragmentary lightcurve gave a rotation period of 30 hours with a brightness amplitude of 0.13 magnitude ({{{1}}}).[8] As of 2017, no secure period has been obtained.[3]

Diameter and albedo

According to the surveys carried out by the Japanese Akari satellite and the NEOWISE mission of NASA's Wide-field Infrared Survey Explorer, Umtata measures between 20.35 and 22.895 kilometers in diameter and its surface has an albedo between 0.0794 and 0.112.[5][6][7]

The Collaborative Asteroid Lightcurve Link assumes an albedo of 0.10 – a compromise value between the stony (0.20) and carbonaceous asteroid's, both abundant in the main belt's central region – and derives a diameter of 20.40 kilometers based on an absolute magnitude of 11.57.[3]

Naming

This minor planet was named after South-African town of Mthatha, formerly known as Umtata. It is the capital town of the OR Tambo District Municipality and the King Sabata Dalindyebo Local Municipality.[2] The official naming citation was published by the Minor Planet Center in April 1953 (M.P.C. 909).[10]

Notes

  1. ↑ Asteroid Lightcurve Data Base (LCDB) – 2. Taxonomic Class, orbital class, and albedo. The LCDB generically assumes a S/C-type with an albedo of 0.10 for non-family main belt asteroids with a semi-major axis between 2.6 and 2.7.

References

  1. ↑ 1.0 1.1 1.2 1.3 1.4 1.5 "JPL Small-Body Database Browser: 1397 Umtata (1936 PG)". Jet Propulsion Laboratory. https://ssd.jpl.nasa.gov/sbdb.cgi?sstr=2001397. Retrieved 17 October 2017. 
  2. ↑ 2.0 2.1 2.2 Schmadel, Lutz D. (2007). "(1397) Umtata". Dictionary of Minor Planet Names – (1397) Umtata. Springer Berlin Heidelberg. p. 113. doi:10.1007/978-3-540-29925-7_1398. ISBN 978-3-540-00238-3. 
  3. ↑ 3.0 3.1 3.2 3.3 3.4 3.5 3.6 3.7 "LCDB Data for (1397) Umtata". Asteroid Lightcurve Database (LCDB). http://www.minorplanet.info/PHP/generateOneAsteroidInfo.php?AstInfo=1397%7CUmtata. Retrieved 17 October 2017. 
  4. ↑ 4.0 4.1 "Asteroid 1397 Umtata – Proper Elements". AstDyS-2, Asteroids – Dynamic Site. https://newton.spacedys.com/astdys/index.php?pc=1.1.6&n=1397. 
  5. ↑ 5.0 5.1 5.2 5.3 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. Bibcode: 2011PASJ...63.1117U.  (online, AcuA catalog p. 153)
  6. ↑ 6.0 6.1 6.2 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. doi:10.1088/0004-637X/791/2/121. Bibcode: 2014ApJ...791..121M. http://adsabs.harvard.edu/cgi-bin/bib_query?bibcode=2014ApJ...791..121M. Retrieved 17 October 2017. 
  7. ↑ 7.0 7.1 7.2 7.3 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. doi:10.1088/0004-637X/741/2/90. Bibcode: 2011ApJ...741...90M. 
  8. ↑ 8.0 8.1 8.2 Binzel, R. P. (October 1987). "A photoelectric survey of 130 asteroids". Icarus 72 (1): 135–208. doi:10.1016/0019-1035(87)90125-4. ISSN 0019-1035. Bibcode: 1987Icar...72..135B. http://adsabs.harvard.edu/cgi-bin/bib_query?bibcode=1987Icar...72..135B. Retrieved 17 October 2017. 
  9. ↑ 9.0 9.1 "1397 Umtata (1936 PG)". Minor Planet Center. https://www.minorplanetcenter.net/db_search/show_object?object_id=1397. Retrieved 17 October 2017. 
  10. ↑ Schmadel, Lutz D. (2009). "Appendix – Publication Dates of the MPCs". Dictionary of Minor Planet Names – Addendum to Fifth Edition (2006–2008). Springer Berlin Heidelberg. p. 221. doi:10.1007/978-3-642-01965-4. ISBN 978-3-642-01964-7. https://archive.org/details/dictionaryminorp2008schm. 

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