3873 Roddy

3873 Roddy

Discovery [1]
Discovered by	C. Shoemaker
Discovery site	Palomar Obs.
Discovery date	21 November 1984
Designations
MPC designation	(3873) Roddy
Named after	David Roddy (American astrogeologist)[2]
Alternative designations	1984 WB · 1953 XK1
Minor planet category	Mars-crosser[1] Hungaria [3][4]
Orbital characteristics [1]
Epoch 4 September 2017 (JD 2458000.5)
Uncertainty parameter 0
Observation arc	32.46 yr (11,855 days)
Aphelion	2.1452 AU
Perihelion	1.6387 AU
Semi-major axis	1.8920 AU
Eccentricity	0.1339
Orbital period (sidereal)	2.60 yr (951 days)
Mean anomaly	140.78°
Mean motion	0° 22^m 43.32^s / day
Inclination	23.357°
Longitude of ascending node	250.06°
Argument of perihelion	267.60°
Known satellites	1 (likely)[5]
Physical characteristics
Dimensions	5.021±0.581[6] 7.13 km (calculated)[4] 7.51±0.25 km[7]
Synodic rotation period	2.4782±0.09 h[8] 2.479±0.001 h[9] 2.4792±0.0001 h[10] 2.4797±0.00006 h[5] 2.480±0.001 h[11] 2.486±0.001 h[12]
Geometric albedo	0.20 (assumed)[4] 0.419±0.164[6] 0.512±0.039[7]
Spectral type	SMASS = S [1] · S [4] · L [13]
Absolute magnitude (H)	12.00[7][13] · 12.8[1] · 13.1[4][14]

3873 Roddy, provisional designation 1984 WB, is a stony Hungarian asteroid, Mars-crosser and suspected binary system,^[5] from the innermost regions of the asteroid belt, approximately 7 kilometers in diameter. It was discovered on 21 November 1984, by American astronomer Carolyn Shoemaker at the Palomar Observatory in California, United States.^[3] It was named after American astrogeologist David Roddy.^[2]

Orbit and classification

Roddy is a member of the Hungaria family, which form the innermost dense concentration of asteroids in the Solar System. It orbits the Sun at a distance of 1.6–2.1 AU once every 2 years and 7 months (951 days). Its orbit has an eccentricity of 0.13 and an inclination of 23° with respect to the ecliptic.^[1] The first precovery was taken at the discovering observatory in 1953, extending the asteroid's observation arc by 31 years prior to its discovery.^[3]

Physical characteristics

In the SMASS classification, Roddy is a common S-type asteroid. It has also been characterized as a rare L-type asteroid.^[13]

Diameter and albedo

According to the surveys carried out by NASA's NEOWISE mission and the Japanese Akari satellite, the asteroid measures 5.0 and 7.5 kilometers, and its surface has an exceptionally high albedo of 0.419 and 0.512, respectively,^[6][7] while the Collaborative Asteroid Lightcurve Link assumes a standard albedo for stony asteroids of 0.20 and calculates a diameter of 7.1 kilometers with an absolute magnitude of 13.1.^[4]

Moon and lightcurve

A large number of photometric observations by American astronomer Brian Warner at the Palmer Divide Observatory (716) in Colorado, were made to measure the asteroid's lightcurve. One of the best results rendered a period of 2.4782 hours and a variation in brightness of 0.05 in magnitude (U=3).^[15] Other lightcurve observations gave a similar period between 2.478 and 2.486 hours.^{[5][8][9][10][11][12]}

While there is strong evidence for an asteroid moon orbiting Roddy, its existence is still uncertain as of 2016. Based on one observation/solution, the satellite has an orbital period of 19.24±0.02 hours and measures about 27% of Roddy's diameter, which is slightly less than 2 kilometers (D_s/D_p ratio of 0.27±0.02). However, an alternative orbital period of 23.8 hours is also possible.^[5]

Naming

This minor planet was named in after David J. Roddy (1932–2002), an American astrogeologist and authority on terrestrial impact craters at the U.S. Geological Survey. He is noted for his mathematical models of impact events and his studies on Devonian impact craters, as well as for using explosives for his field experiments.^[2] The approved naming citation was published by the Minor Planet Center on 12 December 1989 (M.P.C. 15574).^[16]

References

1. "JPL Small-Body Database Browser: 3873 Roddy (1984 WB)" (2017-05-05 last obs.). Jet Propulsion Laboratory. Retrieved 4 July 2017.
2. Schmadel, Lutz D. (2007). "(3873) Roddy". Dictionary of Minor Planet Names – (3873) Roddy. Springer Berlin Heidelberg. p. 329. doi:10.1007/978-3-540-29925-7_3862. ISBN 978-3-540-00238-3.
3. "3873 Roddy (1984 WB)". Minor Planet Center. Retrieved 25 March 2016.
4. "LCDB Data for (3873) Roddy". Asteroid Lightcurve Database (LCDB). Retrieved 25 May 2016.
5. Warner, Brian D. (January 2013). "Rounding Up the Unusual Suspects". The Minor Planet Bulletin. 40 (1): 36–42. Bibcode:2013MPBu...40...36W. ISSN 1052-8091. PMID 32455349. Retrieved 1 March 2016.
6. 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. Retrieved 5 December 2016.
7. 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)
8. Warner, Brian D. (September 2006). "Asteroid lightcurve analysis at the Palmer Divide Observatory - late 2005 and early 2006". The Minor Planet Bulletin. 33 (3): 58–62. Bibcode:2006MPBu...33...58W. ISSN 1052-8091. Retrieved 1 March 2016.
9. Klinglesmith, Daniel A. III; Hendrickx, Sebastian; Madden, Karl; Montgomery, Samuel (April 2016). "Lightcurves for Shape/Spin Models". The Minor Planet Bulletin. 43 (2): 123–128. Bibcode:2016MPBu...43..123K. ISSN 1052-8091. Retrieved 5 December 2016.
10. Warner, Brian D. (June 2008). "Asteroid Lightcurve Analysis at the Palmer Divide Observatory - June - October 2007". The Minor Planet Bulletin. 35 (2): 56–60. Bibcode:2008MPBu...35...56W. ISSN 1052-8091. Retrieved 1 March 2016.
11. Warner, Brian D. (October 2009). "Asteroid Lightcurve Analysis at the Palmer Divide Observatory: 2009 March-June". The Minor Planet Bulletin. 36 (4): 172–176. arXiv:1203.4336. Bibcode:2009MPBu...36..172W. doi:10.1016/j.pss.2012.03.009. ISSN 1052-8091. Retrieved 1 March 2016.
12. Warner, Brian D. (January 2016). "Asteroid Lightcurve Analysis at CS3-Palmer Divide Station: 2015 June-September". The Minor Planet Bulletin. 43 (1): 57–65. Bibcode:2016MPBu...43...57W. ISSN 1052-8091. PMID 32455368. Retrieved 1 March 2016.
13. Carry, B.; Solano, E.; Eggl, S.; DeMeo, F. E. (April 2016). "Spectral properties of near-Earth and Mars-crossing asteroids using Sloan photometry". Icarus. 268: 340–354. arXiv:1601.02087. Bibcode:2016Icar..268..340C. doi:10.1016/j.icarus.2015.12.047. Retrieved 5 December 2016.
14. Faure, Gerard; Garrett, Lawrence (October 2009). "Suggested Revised H Values of Selected Asteroids: Report Number 4". The Minor Planet Bulletin. 36 (4): 140–143. Bibcode:2009MPBu...36..140F. ISSN 1052-8091. Retrieved 1 March 2016.
15. Warner, Brian D. (April 2011). "Asteroid Lightcurve Analysis at the Palmer Divide Observatory: 2010 September-December". The Minor Planet Bulletin. 38 (2): 82–86. Bibcode:2011MPBu...38...82W. ISSN 1052-8091. Retrieved 1 March 2016.
16. "MPC/MPO/MPS Archive". Minor Planet Center. Retrieved 25 May 2016.

External links

• Center for Solar System Studies CS3
• The Palmer Divide Observatory: Tour given by Brian Warner on YouTube (time 4:03 min.)
• Lightcurve plot of 3873 Roddy, Palmer Divide Observatory, B. D. Warner (2009)
• Asteroid Lightcurve Database (LCDB), query form (info Archived 16 December 2017 at the Wayback Machine)
• Asteroids with Satellites, Robert Johnston, johnstonsarchive.net
• 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
• 3873 Roddy at AstDyS-2, Asteroids—Dynamic Site
  • Ephemeris · Observation prediction · Orbital info · Proper elements · Observational info
• 3873 Roddy at the JPL Small-Body Database
  • Close approach · Discovery · Ephemeris · Orbit viewer · Orbit parameters · Physical parameters