Astronomy:946 Poësia

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946 Poësia
Discovery [1]
Discovered byM. F. Wolf
Discovery siteHeidelberg Obs.
Discovery date11 February 1921
Designations
(946) Poësia
Pronunciation/pˈsiə/[6]
Named afterpoetry
(goddess of poetry)[2]
A921 CD · 1959 AA
A911 KB · 1911 KB
1921 JC
Minor planet categorymain-belt [1][3] · (outer)
Themis[4][5]
Orbital characteristics[3]
Epoch 31 May 2020 (JD 2459000.5)
Uncertainty parameter 0
Observation arc98.66 yr (36,034 d)
|{{{apsis}}}|helion}}3.5647 AU
|{{{apsis}}}|helion}}2.6709 AU
3.1178 AU
Eccentricity0.1433
Orbital period5.51 yr (2,011 d)
Mean anomaly30.119°
Mean motion0° 10m 44.4s / day
Inclination1.4312°
Longitude of ascending node69.661°
37.936°
Physical characteristics
Mean diameter
  • 36.210±0.149 km[7]
  • 39.60±0.64 km[8]
  • 43.75±4.6 km[9]
Rotation period108.5±0.5 h[10][11]
Geometric albedo
  • 0.0627±0.015[9]
  • 0.079±0.003[8]
  • 0.097±0.008[7]
  • Tholen = FU [3]
  • Barucci = C0
    B–V = 0.667±0.018[3]
  • U–B = 0.336±0.024[3]
Absolute magnitude (H)10.6[1][3]


946 Poësia /pˈsiə/ is a Themis asteroid and slow rotator, approximately 39 kilometers (24 miles) in diameter, located in the outer regions of the asteroid belt. It was discovered by German astronomer Max Wolf at the Heidelberg-Königstuhl State Observatory on 11 February 1921 and given the provisional designations A921 CD and 1921 JC.[1] The F-type asteroid has a long rotation period of 108.5 hours. It was named after the goddess of poetry.[2]

Orbit and classification

Poësia is a core member of the Themis family (602), a very large family of carbonaceous asteroids, named after 24 Themis.[4][5][12]:23 It orbits the Sun in the outer asteroid belt at a distance of 2.7–3.6 AU once every 5 years and 6 months (2,011 days; semi-major axis of 3.12 AU). Its orbit has an eccentricity of 0.14 and an inclination of 1° with respect to the ecliptic.[3] The body's observation arc begins at Heidelberg Observatory on 11 May 1921, or three months after its official discovery observation.[1]

Naming

This minor planet was named after the goddess of poetry. The name was proposed by Russian astronomer Nikolaj Komendantov (1895–1937), and the naming was mentioned in The Names of the Minor Planets by Paul Herget in 1955 (H 91).[2]

Physical characteristics

In the Tholen classification, Poësia is an uncommon F-type asteroid, though with an unusual spectrum,[3] while in the Barucci taxonomy, it is a carbonaceous C0-type.[5] The overall spectral type for members of the Themistian family is that of a C-type.[12]:23

Rotation period

In January 2009, a rotational lightcurve of Poësia was obtained from photometric observations by Robert Stephens at the Santana Observatory (646) and Goat Mountain Astronomical Research Station (G79) in California. Lightcurve analysis gave an exceptionally long rotation period of 108.5±0.5 hours with a brightness amplitude of 0.32±0.05 magnitude ({{{1}}}).[11] A few weeks later, Gary A. Vander Haagen at Stonegate Observatory (H67) determined an ambiguous period of 73.5 or 102.9 hours with an amplitude of 0.24±0.05 magnitude ({{{1}}}),[13] while René Roy measured a tentative period of 48 hours ({{{1}}}).[14] With a best-rated period of 108.5 hours, Poësia is a slow rotator. While the slowest rotators have periods above 1000 hours, the vast majority of asteroids have periods between 2.2 and 20 hours.

Diameter and albedo

According to the survey carried out by the NEOWISE mission of NASA's Wide-field Infrared Survey Explorer (WISE), and the Infrared Astronomical Satellite IRAS, Poësia measures 36.210±0.149, 39.60±0.64 and 43.75±4.6 kilometers in diameter, and its surface has a corresponding albedo of 0.097±0.008, 0.079±0.003 and 0.0627±0.015, respectively.[7][8][9] The Collaborative Asteroid Lightcurve Link adopts the results from IRAS, that is, an albedo of 0.0627 and a diameter of 43.75 km based on an absolute magnitude of 9.8.[10]

Further published mean-diameters and albedos by the WISE team include 33.30±10.10 km, 35.84±11.06 km, 37.604±0.255 km and 38.990±0.248 km with albedos of 0.06±0.06, 0.06±0.04, 0.097±0.008 and 0.0789±0.0085, respectively.[5][10]

References

  1. 1.0 1.1 1.2 1.3 1.4 "946 Poesia (A921 CD)". Minor Planet Center. https://www.minorplanetcenter.net/db_search/show_object?object_id=946. 
  2. 2.0 2.1 2.2 Schmadel, Lutz D. (2007). "(946) Poësia". Dictionary of Minor Planet Names. Springer Berlin Heidelberg. p. 83. doi:10.1007/978-3-540-29925-7_947. ISBN 978-3-540-00238-3. 
  3. 3.0 3.1 3.2 3.3 3.4 3.5 3.6 3.7 "JPL Small-Body Database Browser: 946 Poesia (A921 CD)". Jet Propulsion Laboratory. https://ssd.jpl.nasa.gov/sbdb.cgi?sstr=2000946. 
  4. 4.0 4.1 "Asteroid 946 Poesia – Proper Elements". AstDyS-2, Asteroids – Dynamic Site. https://newton.spacedys.com/astdys/index.php?pc=1.1.6&n=946. 
  5. 5.0 5.1 5.2 5.3 "Asteroid 946 Poesia". Small Bodies Data Ferret. https://sbntools.psi.edu/ferret/SimpleSearch/results.action?targetName=946+Poesia. 
  6. poesis, poiesis (3rd ed.), Oxford University Press, September 2005, http://oed.com/search?searchType=dictionary&q=poesis%2C+poiesis  (Subscription or UK public library membership required.)
  7. 7.0 7.1 7.2 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. doi:10.1088/0004-637X/791/2/121. Bibcode2014ApJ...791..121M. 
  8. 8.0 8.1 8.2 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 Tedesco, E. F.; Noah, P. V.; Noah, M.; Price, S. D. (October 2004). "IRAS Minor Planet Survey V6.0". NASA Planetary Data System 12: 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 14 February 2020. 
  10. 10.0 10.1 10.2 "LCDB Data for (946) Poësia". Asteroid Lightcurve Database (LCDB). http://www.minorplanet.info/PHP/generateOneAsteroidInfo.php?AstInfo=946. 
  11. 11.0 11.1 Stephens, Robert D. (July 2009). "Asteroids Observed from GMARS and Santana Observatories: 2009 January – February". The Minor Planet Bulletin 36 (3): 125–126. Bibcode2009MPBu...36..125S. http://www.minorplanet.info/MPB/issues/MPB_36-3.pdf. Retrieved 15 February 2020. 
  12. 12.0 12.1 Nesvorný, D.; Broz, M.; Carruba, V. (December 2014). "Identification and Dynamical Properties of Asteroid Families". Asteroids IV: 297–321. doi:10.2458/azu_uapress_9780816532131-ch016. Bibcode2015aste.book..297N. 
  13. Vander Haagen, Gary A. (October 2009). "Lightcurves and H-G Parameters for 901 Brunsia and 946 Poesia". The Minor Planet Bulletin 36 (4): 136–138. Bibcode2009MPBu...36..136V. http://www.minorplanet.info/MPB/issues/MPB_36-4.pdf. 
  14. Behrend, Raoul. "Asteroids and comets rotation curves – (946) Poësia". Geneva Observatory. http://obswww.unige.ch/~behrend/page3cou.html#000946. 

External links