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1451 Granö
Discovery
Discovered by	Y. Väisälä
Discovery site	Turku Obs.
Discovery date	22 February 1938
Designations
MPC designation	(1451) Grano
Named after	Johannes Gabriel Granö; (University of Turku)
Alternative designations	1938 DT · 1976 WK
Minor planet category	main-belt · Flora
Orbital characteristics
	Epoch 4 September 2017 (JD 2458000.5)
	Uncertainty parameter 0
Observation arc	56.21 yr (20,532 days)
Aphelion	2.4619 AU
Perihelion	1.9442 AU
Semi-major axis	2.2030 AU
Eccentricity	0.1175
Orbital period (sidereal)	3.27 yr (1,194 days)
Mean anomaly	60.928°
Mean motion	0° 18m 5.04s / day
Inclination	5.1087°
Longitude of ascending node	175.29°
Argument of perihelion	51.858°
Physical characteristics
Dimensions	6.170±0.072; 6.329±0.037 km; 6.81 km (calculated); 9.70±0.57 km
Synodic rotation period	5.109 h (removed); 138±0.05 h
Geometric albedo	0.171±0.022; 0.20 (assumed); 0.4034±0.0919; 0.429±0.077
Spectral type	S
Absolute magnitude (H)	12.6 · 13.2 · 14.19±0.95

1451 Granö, provisional designation 1938 DT, is a stony Florian asteroid and slow rotator from the inner regions of the asteroid belt, approximately 6.5 kilometers in diameter. It was discovered on 22 February 1938, by Finnish astronomer Yrjö Väisälä at Turku Observatory in Southwest Finland, and later named for Johannes Gabriel Granö, rector of the University of Turku.^[9]

Orbit and classification

The asteroid is a member of the Flora family, a large group of stony S-type asteroids in the main-belt. It orbits the Sun in the inner main-belt at a distance of 1.9–2.5 AU once every 3 years and 3 months (1,194 days). Its orbit has an eccentricity of 0.12 and an inclination of 5° with respect to the ecliptic.^[1] As no precoveries were taken, and no previous identifications were made, Granö's observation arc begins with its official discovery observation in 1938.^[9]

Physical characteristics

Slow rotator

A rotational lightcurve of Granö was obtained from photometric observations made by amateur astronomer Robert Stephens at GMARS and Santana Observatories in March 2010. Analysis gave a long rotation period of 138 hours with a brightness variation of 0.65 magnitude (U=2+).^[7] This makes Granö a slow rotating asteroid. The result supersedes a previous period of 5.1 hours from May 2007 (U=2-).^[a]

Diameter and albedo

According to the surveys carried out by the Japanese Akari satellite and NASA's Wide-field Infrared Survey Explorer with its subsequent NEOWISE mission, Granö measures between 6.17 and 9.70 kilometers in diameter, and its surface has an albedo between 0.171 and 0.429.^[4]^[5]^[6] The Collaborative Asteroid Lightcurve Link assumes a standard albedo for stony asteroids of 0.20 and calculates a diameter of 6.81 kilometers using an absolute magnitude of 13.2.^[3]

Naming

This minor planet was named after Johannes Gabriel Granö (1882−1956), Finnish professor of geography and rector at University of Turku from 1932 to 1934.^[2] The official naming citation was published by the Minor Planet Center on 30 January 1964 (M.P.C. 2277).^[10]

Notes

^ ^a ^b Geneva Obs. Behrend (2007) web: rotation period 5.109±0.004 hours with a brightness amplitude of 0.06 mag. Summary figures for (1451) Grano at Collaborative Asteroid Lightcurve Link (CALL). Results are no longer published on website, see: Asteroids and comets rotation curves CdR – Observatoire de Genève, Raoul Behrend

References

^ ^a ^b ^c ^d "JPL Small-Body Database Browser: 1451 Grano (1938 DT)" (2017-06-03 last obs.). Jet Propulsion Laboratory. Retrieved 25 July 2017.
^ ^a ^b Schmadel, Lutz D. (2007). "(1451) Granö". Dictionary of Minor Planet Names – (1451) Granö. Springer Berlin Heidelberg. p. 116. doi:10.1007/978-3-540-29925-7_1452. ISBN 978-3-540-00238-3.
^ ^a ^b ^c ^d ^e ^f "LCDB Data for (1451) Granö". 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 ^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 Stephens, Robert D. (October 2010). "Asteroids Observed from GMARS and Santana Observatories: 2010 April - June". The Minor Planet Bulletin. 37 (4): 159–161. Bibcode:2010MPBu...37..159S. ISSN 1052-8091. Retrieved 16 December 2016.
^ ^a ^b 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 "1451 Grano (1938 DT)". Minor Planet Center. Retrieved 16 December 2016.
^ Schmadel, Lutz D. "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.