1473 Ounas

1473 Ounas
Discovery
Discovered by	Y. Väisälä
Discovery site	Turku Obs.
Discovery date	22 October 1938
Designations
MPC designation	(1473) Ounas
Named after	Ounasjoki River; (in Finland)
Alternative designations	1938 UT · 1950 NZ; 1950 PB1
Minor planet category	main-belt · (middle)
Orbital characteristics
	Epoch 16 February 2017 (JD 2457800.5)
	Uncertainty parameter 0
Observation arc	77.90 yr (28,452 days)
Aphelion	3.1862 AU
Perihelion	1.9623 AU
Semi-major axis	2.5743 AU
Eccentricity	0.2377
Orbital period (sidereal)	4.13 yr (1,509 days)
Mean anomaly	19.843°
Mean motion	0° 14m 18.96s / day
Inclination	13.651°
Longitude of ascending node	216.52°
Argument of perihelion	129.42°
Physical characteristics
Dimensions	17.62 km (derived); 18.164±0.109; 20.032 km (dated)
Synodic rotation period	16 h (dated); 139.1±0.1 h; 139.1±0.5 h
Geometric albedo	0.0841 (dated); 0.110±0.018; 0.1189 (derived)
Spectral type	S
Absolute magnitude (H)	11.67±0.32 · 11.7 · 11.8

1473 Ounas, provisional designation 1938 UT, is a stony asteroid, suspected tumbler and a slow rotator from the middle region of the asteroid belt, approximately 18 kilometers in diameter. It was discovered on 22 October 1938, by Finnish astronomer Yrjö Väisälä at Turku Observatory in Southwest Finland.^[9] The asteroid was named after the Finnish Ounas river.^[2]

Classification and orbit

Ounas is a S-type asteroid that orbits the Sun in the central main-belt at a distance of 2.0–3.2 AU once every 4 years and 2 months (1,509 days). Its orbit has an eccentricity of 0.24 and an inclination of 14° with respect to the ecliptic.^[1] As no precoveries were taken, and no previous identifications were made, the body's observation arc begins with its official discovery observation at Turku in 1938.^[9]

Physical characteristics

In October 2012/13, a rotational lightcurve of Ounas was obtained from photometric observations by astronomers René Roy, Vladimir Benishek, Andrea Ferrero, Daniel Klinglesmith, Frederick Pilcher, Raoul Behrend and Petr Pravec. It gave a well-defined rotation period of 139.1 hours with a brightness variation of 0.6 magnitude (U=3/3).^[6]^[7] Ounas is a suspected "tumbler", which have a non-principal axis rotation (NPAR).^[6]

According to the survey carried out by NASA's Wide-field Infrared Survey Explorer with its subsequent NEOWISE mission, the asteroid measures 18.16 kilometers in diameter and its surface has an albedo of 0.11.^[4]^[5] The Collaborative Asteroid Lightcurve Link derives an albedo of 0.1189 and a diameter of 17.62 kilometers with an absolute magnitude of 11.7.^[3]

Naming

This minor planet was named after the Ounas river, one of the principal rivers in Finland.^[2] The official naming citation was published by the Minor Planet Center on 20 February 1976 (M.P.C. 3928).^[10]

References

^ ^a ^b ^c ^d "JPL Small-Body Database Browser: 1473 Ounas (1938 UT)" (2016-11-05 last obs.). Jet Propulsion Laboratory. Retrieved 16 December 2016.
^ ^a ^b ^c Schmadel, Lutz D. (2007). "(1473) Ounas". Dictionary of Minor Planet Names – (1473) Ounas. Springer Berlin Heidelberg. p. 118. doi:10.1007/978-3-540-29925-7_1474. ISBN 978-3-540-00238-3.
^ ^a ^b ^c ^d ^e ^f ^g "LCDB Data for (1473) Ounas". Asteroid Lightcurve Database (LCDB). Retrieved 16 December 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. Retrieved 16 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.
^ ^a ^b ^c Pilcher, Frederick; Benishek, Vladimir; Ferrero, Andrea; Klinglesmith, Daniel A. III; Pravec, Petr; Roy, Rene; et al. (July 2013). "New Photometry of 1473 Ounas". The Minor Planet Bulletin. 40 (3): 126–129. Bibcode:2013MPBu...40..126P. ISSN 1052-8091. Retrieved 16 December 2016.
^ ^a ^b Behrend, Raoul. "Asteroids and comets rotation curves – (1473) Ounas". Geneva Observatory. Retrieved 16 December 2016.
^ 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 16 December 2016.
^ ^a ^b "1473 Ounas (1938 UT)". Minor Planet Center. Retrieved 16 December 2016.
^ 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

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
1473 Ounas at AstDyS-2, Asteroids—Dynamic Site
- Ephemeris · Observation prediction · Orbital info · Proper elements · Observational info
1473 Ounas at the JPL Small-Body Database
- Close approach · Discovery · Ephemeris · Orbit viewer · Orbit parameters · Physical parameters

[jpldata-1] "JPL Small-Body Database Browser: 1473 Ounas (1938 UT)" (2016-11-05 last obs.). Jet Propulsion Laboratory. Retrieved 16 December 2016.

[springer-2] Schmadel, Lutz D. (2007). "(1473) Ounas". Dictionary of Minor Planet Names – (1473) Ounas. Springer Berlin Heidelberg. p. 118. doi:10.1007/978-3-540-29925-7_1474. ISBN 978-3-540-00238-3.

[lcdb-3] ^ ^a ^b ^c ^d ^e ^f ^g "LCDB Data for (1473) Ounas". Asteroid Lightcurve Database (LCDB). Retrieved 16 December 2016.

[Masiero-2014-4] 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 16 December 2016.

[WISE-5] 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.

[Pilcher-2013f-6] Pilcher, Frederick; Benishek, Vladimir; Ferrero, Andrea; Klinglesmith, Daniel A. III; Pravec, Petr; Roy, Rene; et al. (July 2013). "New Photometry of 1473 Ounas". The Minor Planet Bulletin. 40 (3): 126–129. Bibcode:2013MPBu...40..126P. ISSN 1052-8091. Retrieved 16 December 2016.

[geneva-obs-7] Behrend, Raoul. "Asteroids and comets rotation curves – (1473) Ounas". Geneva Observatory. Retrieved 16 December 2016.

[Veres-2015-8] 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 16 December 2016.

[MPC-Ounas-9] "1473 Ounas (1938 UT)". Minor Planet Center. Retrieved 16 December 2016.

[DoMP-Circular-dates-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.

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