2391 Tomita, provisional designation 1957 AA, is a Nysian asteroid from the inner regions of the asteroid belt, approximately 15 kilometers in diameter. The asteroid was discovered on 9 January 1957, by German astronomer Karl Reinmuth at Heidelberg Observatory in southern Germany.[10] It was named after Japanese astronomer Kōichirō Tomita.[2]
| Discovery [1] | |
|---|---|
| Discovered by | K. Reinmuth |
| Discovery site | Heidelberg Obs. |
| Discovery date | 9 January 1957 |
| Designations | |
| (2391) Tomita | |
Named after | Kōichirō Tomita (Japanese astronomer)[2] |
| 1957 AA · 1929 VX 1938 BF · 1942 DF 1957 BA · 1977 KM 1978 PA4 · 1980 DC6 | |
| main-belt · Nysa [3] | |
| Orbital characteristics [1] | |
| Epoch 4 September 2017 (JD 2458000.5) | |
| Uncertainty parameter 0 | |
| Observation arc | 87.07 yr (31,804 days) |
| Aphelion | 2.7676 AU |
| Perihelion | 2.1141 AU |
| 2.4408 AU | |
| Eccentricity | 0.1339 |
| 3.81 yr (1,393 days) | |
| 345.07° | |
| 0° 15m 30.6s / day | |
| Inclination | 3.0111° |
| 163.32° | |
| 282.65° | |
| Physical characteristics | |
| Dimensions | 9.17 km (calculated)[3] 15.07±4.33 km[4] 15.20±3.74 km[5] 16.62±0.23 km[6] 17.941±0.129[7] 19.412±0.175 km[8] |
| 7.9533±0.0005 h[a] 8.435±0.079 h[b] | |
| 0.0321±0.0044[8] 0.06±0.03[5] 0.070±0.004[6] 0.07±0.07[4][7] 0.21 (assumed)[3] | |
| S [3] · C [9] | |
| 12.4[4][6][8] · 12.5[1][3] · 12.66[5] · 12.74±0.28[9] | |
Orbit and classification
editTomita is a member of the Nysa family, which is named after its most massive member 44 Nysa. It orbits the Sun in the inner main-belt at a distance of 2.1–2.8 AU once every 3 years and 10 months (1,393 days). Its orbit has an eccentricity of 0.13 and an inclination of 3° with respect to the ecliptic.[1]
A first precovery was taken at Lowell Observatory in 1929, extending the body's observation arc by 28 years prior to its official discovery observation at Heidelberg.[10]
Physical characteristics
editTomita has been characterized as a stony S-type asteroid by the Collaborative Asteroid Lightcurve Link (CALL), and as a carbonaceous C-type asteroid by Pan-STARRS' photometric survey.[3][9]
Diameter and albedo
editAccording to the surveys carried out by NASA's Wide-field Infrared Survey Explorer with its subsequent NEOWISE mission, the asteroid measures between 15.07 and 19.4 kilometers in diameter and its surface has a low albedo between 0.03 and 0.07, respectively.[4][5][6][7][8]
As CALL considers the body to be of a stony composition, it assumes a much higher albedo of 0.21 and calculates a diameter of 9.2 kilometers, as the higher the asteroid's reflectivity (albedo), the shorter its diameter at a constant absolute magnitude (brightness).[3]
Rotation period
editIn December 2013, two rotational lightcurves were obtained for this asteroid from photometric observations. They gave a rotation period of 7.9533±0.0005 and 8.435±0.079 hours with a brightness variation of 0.14 and 0.15 in magnitude, respectively. (U=3/n.a.).[a][b]
Naming
editThis minor planet was named in honor of Japanese astronomer Kōichirō Tomita (1925–2006), long-time observer at the Tokyo Astronomical Observatory, and a discoverer of minor planets and comets himself. Tomita was also known as one of Japan's principal popularizer of astronomy.[2] The official naming citation was published by the Minor Planet Center on 14 April 1987 (M.P.C. 11748).[11]
Notes
edit- ^ a b Pravec (2013) web: lightcurve plot with a rotation period 7.9533±0.0005 hours with a brightness amplitude of 0.14 mag. Summary figures for (2391) Tomita at Collaborative Asteroid Lightcurve Link (CALL) and Pravec, P.; Wolf, M.; Sarounova, L. (2013)
- ^ a b Williams (2013) web: rotation period 8.435±0.079 hours with a brightness amplitude of 0.15 mag. Summary figures for (2391) Tomita at Collaborative Asteroid Lightcurve Link (CALL). Data by Williams, R. (2013), posted on CALL page.
References
edit- ^ a b c d "JPL Small-Body Database Browser: 2391 Tomita (1957 AA)" (2016-11-23 last obs.). Jet Propulsion Laboratory. Retrieved 13 June 2017.
- ^ a b c Schmadel, Lutz D. (2007). "(2391) Tomita". Dictionary of Minor Planet Names – (2391) Tomita. Springer Berlin Heidelberg. p. 195. doi:10.1007/978-3-540-29925-7_2392. ISBN 978-3-540-00238-3.
- ^ a b c d e f g "LCDB Data for (2391) Tomita". Asteroid Lightcurve Database (LCDB). Retrieved 14 August 2016.
- ^ a b c d Nugent, C. R.; Mainzer, A.; Masiero, J.; Bauer, J.; Cutri, R. M.; Grav, T.; et al. (December 2015). "NEOWISE Reactivation Mission Year One: Preliminary Asteroid Diameters and Albedos". The Astrophysical Journal. 814 (2): 13. arXiv:1509.02522. Bibcode:2015ApJ...814..117N. doi:10.1088/0004-637X/814/2/117. S2CID 9341381. Retrieved 13 June 2017.
- ^ a b c d 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.
- ^ a b c d 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 14 August 2016.
- ^ 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. S2CID 119293330. Retrieved 7 December 2016.
- ^ 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. S2CID 35447010. Retrieved 14 August 2016.
- ^ a b c Veres, Peter; Jedicke, Robert; Fitzsimmons, Alan; Denneau, Larry; Granvik, Mikael; Bolin, Bryce; et al. (November 2015). "Absolute magnitudes and slope parameters for 250,000 asteroids observed by Pan-STARRS PS1 - Preliminary results". Icarus. 261: 34–47. arXiv:1506.00762. Bibcode:2015Icar..261...34V. doi:10.1016/j.icarus.2015.08.007. S2CID 53493339. Retrieved 14 August 2016.
- ^ a b "2391 Tomita (1957 AA)". Minor Planet Center. Retrieved 14 August 2016.
- ^ "MPC/MPO/MPS Archive". Minor Planet Center. Retrieved 14 August 2016.
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
- 2391 Tomita at AstDyS-2, Asteroids—Dynamic Site
- 2391 Tomita at the JPL Small-Body Database
