2104 Toronto

2104 Toronto, provisional designation 1963 PD, is a metallic background asteroid from the outer regions of the asteroid belt, approximately 36 kilometers in diameter. It was discovered on 15 August 1963, by Karl Kamper at the David Dunlap Observatory on plates taken by Sidney van den Bergh at the Karl Schwarzschild Observatory in Tautenburg, Germany. The asteroid was named after the University of Toronto. It was the first asteroid discovered at an observatory in Canada.^[2][11]

2104 Toronto

Discovery [1]
Discovered by	K. W. Kamper
Discovery site	Karl Schwarzschild Obs.
Discovery date	15 August 1963
Designations
MPC designation	(2104) Toronto
Named after	University of Toronto [2]
Alternative designations	1963 PD · 1955 HW
Minor planet category	main-belt · (outer) [3] background [4]
Orbital characteristics [1]
Epoch 4 September 2017 (JD 2458000.5)
Uncertainty parameter 0
Observation arc	61.93 yr (22,619 days)
Aphelion	3.5735 AU
Perihelion	2.8031 AU
Semi-major axis	3.1883 AU
Eccentricity	0.1208
Orbital period (sidereal)	5.69 yr (2,079 days)
Mean anomaly	359.45°
Mean motion	0° 10m 23.16s / day
Inclination	18.379°
Longitude of ascending node	252.48°
Argument of perihelion	291.78°
Physical characteristics
Dimensions	26.96±0.60 km[5] 35.864±0.383 km[6] 35.874±0.503 km[7] 37.13±0.58 km[8] 61.04 km (calculated)[3]
Synodic rotation period	8.9669±0.0002 h[9] 8.97±0.01 h[a]
Geometric albedo	0.057 (assumed)[3] 0.099±0.004[8] 0.104±0.011[7] 0.1062±0.0280[6] 0.292±0.031[5]
Spectral type	M [6] · C (assumed)[3]
Absolute magnitude (H)	9.66±0.36[10] · 9.80[1][3][5] · 10.30[6][8]

Orbit and classification

Toronto is a non-family asteroid from the main belt's background population.^[4] It orbits the Sun in the outer main-belt at a distance of 2.8–3.6 AU once every 5 years and 8 months (2,079 days; semi-major axis of 3.19 AU). Its orbit has an eccentricity of 0.12 and an inclination of 18° with respect to the ecliptic.^[1]

The body's observation arc begins with a precovery taken at Palomar Observatory in August 1951, or 12 years prior to its official discovery observation at Tautenburg.^[11]

Physical characteristics

Toronto has been characterized as a metallic M-type asteroid by the Wide-field Infrared Survey Explorer (WISE).^[6] It is also an assumed C-type asteroid.^[3]

Rotation period

Two rotational lightcurves of Toronto have been obtained from photometric observations (U=2+/3).^[9][a] The consolidated lightcurve gave a rotation period of 8.97 hours with a brightness amplitude between 0.26 and 0.32 magnitude.^[3]

Diameter and albedo

According to the surveys carried out by the Japanese Akari satellite and the NEOWISE mission of NASA's WISE telescope, Toronto measures between 26.96 and 37.13 kilometers in diameter and its surface has an albedo between 0.099 and 0.292.^[5][6][7][8]

The Collaborative Asteroid Lightcurve Link assumes a standard albedo for carbonaceous asteroids of 0.057 and consequently calculates a much larger diameter of 61.04 kilometers based on an absolute magnitude of 9.8.^[3]

Naming

This minor planet was named after the University of Toronto which was celebrating its sesquicentennial at the time of its discovery. It was the first minor planet to be discovered at an observatory in Canada (despite the fact that the credited discovery site is located in Germany). The naming also emphasized the university's central role in the development of Canadian astronomy.^[2][12] The official naming citation was published by the Minor Planet Center on 1 February 1979 (M.P.C. 4645).^[13]

Notes

1. Aznar (2016) web. Observation of (2104) Toronto from November 2015: Rotation period 8.97±0.01 hours with a brightness amplitude of 0.26±0.02 mag. Quality Code of 3. Summary figures for at the LCDB

References

1. "JPL Small-Body Database Browser: 2104 Toronto (1963 PD)" (2017-03-30 last obs.). Jet Propulsion Laboratory. Retrieved 5 December 2017.
2. Schmadel, Lutz D. (2007). "(2104) Toronto". Dictionary of Minor Planet Names – (2104) Toronto. Springer Berlin Heidelberg. p. 171. doi:10.1007/978-3-540-29925-7_2105. ISBN 978-3-540-00238-3.
3. "LCDB Data for (2104) Toronto". Asteroid Lightcurve Database (LCDB). Retrieved 5 December 2017.
4. "Asteroid 2104 Toronto – Proper Elements". AstDyS-2, Asteroids – Dynamic Site. Retrieved 29 October 2019.
5. 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. Retrieved 5 December 2017.
6. 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.
7. 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.
8. 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)
9. Oey, Julian (December 2006). "Lightcurves analysis of 10 asteroids from Leura Observatory". The Minor Planet Bulletin. 33 (4): 96–99. Bibcode:2006MPBu...33...96O. ISSN 1052-8091. Retrieved 5 December 2017.
10. 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. Retrieved 5 December 2017.
11. "2104 Toronto (1963 PD)". Minor Planet Center. Retrieved 5 December 2017.
12. Canadian Asteroids, The Royal Astronomy Society of Canada, 22 July 2008, archived from the original on 1 February 2009, retrieved 5 December 2017
13. 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.