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]
| Discovery[1] | |
|---|---|
| Discovered by | C. Jackson |
| Discovery site | Johannesburg Obs. |
| Discovery date | 9 August 1936 |
| Designations | |
| (1397) Umtata | |
Named after | Mthatha[2] (South-African town) |
| 1936 PG · 1931 GK 1945 QF · 1945 RC 1948 EB1 | |
| main-belt · (middle)[3] background[4] | |
| Orbital characteristics[1] | |
| Epoch 4 September 2017 (JD 2458000.5) | |
| Uncertainty parameter 0 | |
| Observation arc | 81.14 yr (29,638 days) |
| Aphelion | 3.3646 AU |
| Perihelion | 1.9967 AU |
| 2.6806 AU | |
| Eccentricity | 0.2551 |
| 4.39 yr (1,603 days) | |
| 173.37° | |
| 0° 13m 28.56s / day | |
| Inclination | 3.5109° |
| 77.437° | |
| 206.53° | |
| Physical characteristics | |
| Dimensions | 20.35±0.30 km[5] 20.40 km (derived)[3] 20.798±0.292 km[6] 22.895±0.285 km[7] |
| 30 h[8] | |
| 0.0794±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] | |
| 11.47[1][5] · 11.57[3][7][8] | |
Orbit and classification
editUmtata 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
editThe 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][a]
Rotation period
editIn 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 (U=1).[8] As of 2017, no secure period has been obtained.[3]
Diameter and albedo
editAccording 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
editThis 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
edit- ^ 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
edit- ^ a b c d e f "JPL Small-Body Database Browser: 1397 Umtata (1936 PG)" (2017-10-01 last obs.). Jet Propulsion Laboratory. Retrieved 17 October 2017.
- ^ a b c 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.
- ^ a b c d e f g h "LCDB Data for (1397) Umtata". Asteroid Lightcurve Database (LCDB). Retrieved 17 October 2017.
- ^ a b "Asteroid 1397 Umtata – Proper Elements". AstDyS-2, Asteroids – Dynamic Site. Retrieved 29 October 2019.
- ^ a b c d 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 c 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. Retrieved 17 October 2017.
- ^ a b c d 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.
- ^ a b c Binzel, R. P. (October 1987). "A photoelectric survey of 130 asteroids". Icarus. 72 (1): 135–208. Bibcode:1987Icar...72..135B. doi:10.1016/0019-1035(87)90125-4. ISSN 0019-1035. Retrieved 17 October 2017.
- ^ a b "1397 Umtata (1936 PG)". Minor Planet Center. Retrieved 17 October 2017.
- ^ 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.
External links
edit- Asteroid Lightcurve Database (LCDB), query form (info Archived 16 December 2017 at the Wayback Machine)
- 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
- 1397 Umtata at AstDyS-2, Asteroids—Dynamic Site
- 1397 Umtata at the JPL Small-Body Database
