Astronomy:1512 Oulu

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1512 Oulu
1512 Oulu Hubble.jpg
Hubble Space Telescope image of Oulu taken in 2012
Discovery[1]
Discovered byH. Alikoski
Discovery siteTurku Obs.
Discovery date18 March 1939
Designations
(1512) Oulu
Named afterOulu (Finnish town)[2]
1939 FE · 1938 CU
1957 TA · 1958 XS
Minor planet categorymain-belt · Hilda[3]
Orbital characteristics[1]
Epoch 4 September 2017 (JD 2458000.5)
Uncertainty parameter 0
Observation arc78.06 yr (28,510 days)
|{{{apsis}}}|helion}}4.5541 AU
|{{{apsis}}}|helion}}3.3892 AU
3.9717 AU
Eccentricity0.1466
Orbital period7.92 yr (2,891 days)
Mean anomaly333.83°
Mean motion0° 7m 28.2s / day
Inclination6.4785°
Longitude of ascending node10.168°
238.20°
Jupiter MOID0.6287 AU
Physical characteristics
Dimensions65.0 km[4]
65.000±4.137 km[5]
79.222±0.241 km[6]
82.72±2.5 km (IRAS:38)[7]
91.05±2.20 km[8]
Rotation period132.3±0.1 h[9]
Geometric albedo0.031±0.001[8]
0.0366±0.002 (IRAS:38)[7]
0.038±0.005[6]
0.0536±0.0061[5]
0.0594[4]
0.06±0.03[10]
Tholen = P[1] · X[11] · P[3]
B–V = 0.715[1]
U–B = 0.190[1]
Absolute magnitude (H)9.62[1][3][5][4][7][8] · 9.92±0.40[11]


1512 Oulu, provisional designation 1939 FE, is a dark Hildian asteroid, slow rotator and possibly the largest known tumbler orbiting in the outermost region of the asteroid belt. With a diameter of approximately 80 kilometers, it belongs to the fifty largest asteroids in the outer main-belt. The body was discovered on 18 March 1939, by Finnish astronomer Heikki Alikoski at Turku Observatory in Southwest Finland and named for the Finnish town Oulu.[2][12]

Orbit and classification

Located in the outermost part of the main-belt, Oulu is a member of the Hilda family, a large orbital group of asteroids that are thought to have originated from the Kuiper belt. They orbit in a 3:2 orbital resonance with the gas giant Jupiter, meaning that for every 2 orbits Jupiter completes around the Sun, a Hildian asteroid will complete 3 orbits.[1] As it does not cross the path of any of the planets, it will not be pulled out of orbit by Jupiter's gravitational field, and will likely remain in a stable orbit for thousands of years.

It orbits the Sun at a distance of 3.4–4.6 AU once every 7 years and 11 months (2,891 days). Its orbit has an eccentricity of 0.15 and an inclination of 6° concerning the ecliptic.[1] In 1938, Oulu was first identified as 1938 CU at Bergedorf Observatory. Its observation arc, however, begins one month after its official discovery observation.[12]

Physical characteristics

Oulu is characterized as a dark and reddish P-type asteroid in the Tholen taxonomy, of which only a few dozen bodies are currently known.[13]

Slow rotator and likely tumbler

In May 2009, a rotational light curve of Oulu was obtained from photometric observations by Slovak astronomer Adrián Galád at Modra Observatory. Lightcurve analysis gave a rotation period of 132.3 hours with a brightness variation of 0.33 in magnitude ({{{1}}}).[9] It is among the top few hundred slow rotators.

Oulu is likely in a state of non-principal axis rotation, which is commonly known as tumbling. It is the largest such object ever observed (also see List of tumblers).[3][9][14]

Diameter and albedo

According to the surveys carried out by the Infrared Astronomical Satellite IRAS, the Japanese Akari satellite, and NASA's Wide-field Infrared Survey Explorer with its subsequent NEOWISE mission, Oulu measures between 65.00 and 91.05 kilometers in diameter, and its surface has an albedo between 0.031 and 0.06.[5][6][7][8][10]

The Collaborative Asteroid Lightcurve Link agrees with IRAS, that is, an albedo of 0.0366 and a diameter of 82.72 kilometers using an absolute magnitude of 9.62.[3] In May 2002, Vasilij Shevchenko and Edward Tedesco observed an occultation by Oulu, that gave a diameter of 65.0 kilometers with an occultation albedo of 0.0594.[4]

Naming

This minor planet was named for the northern Finnish town Oulu, the birthplace of the discoverer.[2] The official naming citation was published by the Minor Planet Center on 30 January 1964 (M.P.C. 2278).[15]

References

  1. 1.0 1.1 1.2 1.3 1.4 1.5 1.6 1.7 "JPL Small-Body Database Browser: 1512 Oulu (1939 FE)". Jet Propulsion Laboratory. https://ssd.jpl.nasa.gov/sbdb.cgi?sstr=2001512. Retrieved 5 June 2017. 
  2. 2.0 2.1 2.2 Schmadel, Lutz D. (2007). "(1512) Oulu". Dictionary of Minor Planet Names. Springer Berlin Heidelberg. p. 120. doi:10.1007/978-3-540-29925-7_1513. ISBN 978-3-540-00238-3. 
  3. 3.0 3.1 3.2 3.3 3.4 "LCDB Data for (1512) Oulu". Asteroid Lightcurve Database (LCDB). http://www.minorplanet.info/PHP/generateOneAsteroidInfo.php?AstInfo=1512%7COulu. Retrieved 4 January 2017. 
  4. 4.0 4.1 4.2 4.3 Shevchenko, Vasilij G.; Tedesco, Edward F. (September 2006). "Asteroid albedos deduced from stellar occultations". Icarus 184 (1): 211–220. doi:10.1016/j.icarus.2006.04.006. Bibcode2006Icar..184..211S. http://adsabs.harvard.edu/cgi-bin/bib_query?bibcode=2006Icar..184..211S. Retrieved 4 January 2017. 
  5. 5.0 5.1 5.2 5.3 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. doi:10.1088/0004-637X/741/2/90. Bibcode2011ApJ...741...90M. 
  6. 6.0 6.1 6.2 Grav, T.; Mainzer, A. K.; Bauer, J.; Masiero, J.; Spahr, T.; McMillan, R. S. et al. (January 2012). "WISE/NEOWISE Observations of the Hilda Population: Preliminary Results". The Astrophysical Journal 744 (2): 15. doi:10.1088/0004-637X/744/2/197. Bibcode2012ApJ...744..197G. http://adsabs.harvard.edu/cgi-bin/bib_query?bibcode=2012ApJ...744..197G. Retrieved 31 December 2016. 
  7. 7.0 7.1 7.2 7.3 Tedesco, E. F.; Noah, P. V.; Noah, M.; Price, S. D. (October 2004). "IRAS Minor Planet Survey V6.0". NASA Planetary Data System – IRAS-A-FPA-3-RDR-IMPS-V6.0. Bibcode2004PDSS...12.....T. https://sbnarchive.psi.edu/pds3/iras/IRAS_A_FPA_3_RDR_IMPS_V6_0/data/diamalb.tab. Retrieved 17 October 2019. 
  8. 8.0 8.1 8.2 8.3 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. doi:10.1093/pasj/63.5.1117. Bibcode2011PASJ...63.1117U.  (online, AcuA catalog p. 153)
  9. 9.0 9.1 9.2 Galad, Adrian; Kornos, Leonard; Vilagi, Jozef (January 2010). "An Ensemble of Lightcurves from Modra". The Minor Planet Bulletin 37 (1): 9–15. ISSN 1052-8091. Bibcode2010MPBu...37....9G. http://adsabs.harvard.edu/cgi-bin/bib_query?bibcode=2010MPBu...37....9G. Retrieved 4 January 2017. 
  10. 10.0 10.1 Mainzer, A.; Grav, T.; Masiero, J.; Bauer, J.; Wright, E.; Cutri, R. M. et al. (August 2011). "Thermal Model Calibration for Minor Planets Observed with Wide-field Infrared Survey Explorer/NEOWISE". The Astrophysical Journal 736 (2): 9. doi:10.1088/0004-637X/736/2/100. Bibcode2011ApJ...736..100M. http://adsabs.harvard.edu/cgi-bin/bib_query?bibcode=2011ApJ...736..100M. Retrieved 6 December 2015. 
  11. 11.0 11.1 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. doi:10.1016/j.icarus.2015.08.007. Bibcode2015Icar..261...34V. http://adsabs.harvard.edu/cgi-bin/bib_query?bibcode=2015Icar..261...34V. Retrieved 4 January 2017. 
  12. 12.0 12.1 "1512 Oulu (1939 FE)". Minor Planet Center. https://www.minorplanetcenter.net/db_search/show_object?object_id=1512. Retrieved 4 January 2017. 
  13. "JPL Small-Body Database Search Engine: spec. type = P (Tholen)". JPL Solar System Dynamics. http://ssd.jpl.nasa.gov/sbdb_query.cgi?obj_group=all;obj_kind=all;obj_numbered=all;OBJ_field=0;ORB_field=0;c1_group=OBJ;c1_item=Ay;c1_op=%3D;c1_value=P;table_format=HTML;max_rows=100;format_option=comp;c_fields=AcBhBgBjBiBnBsAiArApAxAy;.cgifields=format_option;.cgifields=obj_kind;.cgifields=obj_group;.cgifields=obj_numbered;.cgifields=ast_orbit_class;.cgifields=table_format;.cgifields=com_orbit_class&query=1&c_sort=AyA. Retrieved 2015-06-17. 
  14. Pravec, P.; Scheirich, P.; Durech, J.; Pollock, J.; Kusnirák, P.; Hornoch, K. et al. (May 2014). "The tumbling spin state of (99942) Apophis". Icarus 233: 48–60. doi:10.1016/j.icarus.2014.01.026. Bibcode2014Icar..233...48P. http://adsabs.harvard.edu/cgi-bin/bib_query?bibcode=2014Icar..233...48P. Retrieved 23 November 2017. 
  15. 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. Bibcode2009dmpn.book.....S. https://archive.org/details/dictionaryminorp2008schm. 

External links