Astronomy:989 Schwassmannia

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989 Schwassmannia
Discovery [1]
Discovered byA. Schwassmann
Discovery siteBergedorf Obs.
Discovery date18 November 1922
Designations
(989) Schwassmannia
Pronunciation/ʃwæsˈmæniə, ʃvɑːs-/
Named afterFriedrich Karl Arnold Schwassmann
(discoverer himself)[2]
A922 WD · 1922 MW
1935 UE · 1935 UF
Minor planet categorymain-belt [1][3] · (middle)
background [4]
Orbital characteristics [3]
Epoch 27 April 2019 (JD 2458600.5)
Uncertainty parameter 0
Observation arc96.49 yr (35,244 d)
|{{{apsis}}}|helion}}3.3261 AU
|{{{apsis}}}|helion}}1.9915 AU
2.6588 AU
Eccentricity0.2510
Orbital period4.34 yr (1,584 d)
Mean anomaly83.840°
Mean motion0° 13m 38.28s / day
Inclination14.700°
Longitude of ascending node243.40°
165.73°
Physical characteristics
Mean diameter
  • 12.20±1.12 km[5]
  • 12.630±0.124 km[6]
  • 12.86±0.8 km[7]
Rotation period107.85±0.01 h[8][9]
Geometric albedo
  • 0.2035±0.027[7]
  • 0.226±0.043[5]
  • 0.306±0.064[6]
Absolute magnitude (H)11.8[1][3]


989 Schwassmannia (prov. designation: A922 WD or 1922 MW) is a stony background asteroid and a slow rotator from the central regions of the asteroid belt, approximately 12.5 kilometers (7.8 miles) in diameter. It was discovered on 18 November 1922, by astronomer Friedrich Karl Arnold Schwassmann at the Bergedorf Observatory in Hamburg, Germany.[1] The bright S/T-type asteroid has a long rotation period of 107.9 hours.[4] It was named after the discoverer himself.[2]

Orbit and classification

Schwassmannia is a non-family asteroid of the main belt's background population when applying the hierarchical clustering method to its proper orbital elements.[11] It orbits the Sun in the central main-belt at a distance of 2.0–3.3 AU once every 4 years and 4 months (1,584 days; semi-major axis of 2.66 AU). Its orbit has an eccentricity of 0.25 and an inclination of 15° with respect to the ecliptic.[3] The body's observation arc begins at the Heidelberg Observatory on 12 November 1922, just 6 days prior to its official discovery observation at the Bergedorf Observatory in Hamburg.[1]

Naming

Physical characteristics

In the Tholen- and SMASS-like taxonomy of the Small Solar System Objects Spectroscopic Survey (S3OS2), Schwassmannia is an S-type and T-type asteroid, respectively.[4][10]

Rotation period

In November 2013, a rotational lightcurve of Schwassmannia was obtained from photometric observations by astronomers Vladimir Benishek at Sopot Astronomical Observatory (K90), Serbia, American Frederick Pilcher at his Organ Mesa Observatory (G50), New Mexico, and Luis Martinez at Lenomiya Observatory (H13) at Casa Grande in Arizona. Lightcurve analysis gave a well-defined rotation period of 107.85±0.01 hours with a brightness amplitude of 0.35±0.02 magnitude ({{{1}}}).[8][9] Alternative observations with a lower rated quality by Robert Stephens at the Center for Solar System Studies (U81) in September 2013 gave a period of 120.3±1 hours ({{{1}}}).[12][lower-alpha 1] The results supersede an earlier, tentative observation by Italian Federico Manzini at the Sozzago Astronomical Station (A12) from October 2004, with an incorrect period 4.5 hours ({{{1}}}).[4][13]

Diameter and albedo

According to the surveys carried out by the Infrared Astronomical Satellite IRAS, the Japanese Akari satellite and the NEOWISE mission of NASA's WISE telescope, Schwassmannia measures between 12.20±1.12 and 12.86±0.8 kilometers in diameter and its surface has a high albedo between 0.20 and 0.31.[5][6][7] The Collaborative Asteroid Lightcurve Link adopts the result from IRAS, that is, an albedo of 0.2037 and a diameter of 12.86 kilometers based on an absolute magnitude of 11.8.[8]

Notes

  1. ↑ Lightcurve plot of (989) Schwassmannia by Robert Stephens with a rotation period 120.3±1 hours and a brightness amplitude of 0.39±0.05 mag. Quality code for this lightcurve is "2" at the LCDB. Summary figures at the Center for Solar System Studies and LCDB

References

  1. ↑ 1.0 1.1 1.2 1.3 1.4 "989 Schwassmannia (A922 WD)". Minor Planet Center. https://www.minorplanetcenter.net/db_search/show_object?object_id=989. 
  2. ↑ 2.0 2.1 Schmadel, Lutz D. (2007). "(989) Schwassmannia". Dictionary of Minor Planet Names. Springer Berlin Heidelberg. p. 86. doi:10.1007/978-3-540-29925-7_990. ISBN 978-3-540-00238-3. 
  3. ↑ 3.0 3.1 3.2 3.3 "JPL Small-Body Database Browser: 989 Schwassmannia (A922 WD)". Jet Propulsion Laboratory. https://ssd.jpl.nasa.gov/sbdb.cgi?sstr=2000989. 
  4. ↑ 4.0 4.1 4.2 4.3 "Asteroid 989 Schwassmannia". Small Bodies Data Ferret. https://sbntools.psi.edu/ferret/SimpleSearch/results.action?targetName=989+Schwassmannia. 
  5. ↑ 5.0 5.1 5.2 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. Bibcode: 2011PASJ...63.1117U.  (online, AcuA catalog p. 153)
  6. ↑ 6.0 6.1 6.2 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. Bibcode: 2014ApJ...791..121M. 
  7. ↑ 7.0 7.1 7.2 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. Bibcode: 2004PDSS...12.....T. https://sbnarchive.psi.edu/pds3/iras/IRAS_A_FPA_3_RDR_IMPS_V6_0/data/diamalb.tab. Retrieved 4 February 2020. 
  8. ↑ 8.0 8.1 8.2 "LCDB Data for (989) Schwassmannia". Asteroid Lightcurve Database (LCDB). http://www.minorplanet.info/PHP/generateOneAsteroidInfo.php?AstInfo=989. 
  9. ↑ 9.0 9.1 Benishek, Vladimir; Pilcher, Frederick; Martinez, Luis (April 2014). "Rotation Period Determination for 989 Schwassmannia". Minor Planet Bulletin 41 (2): 133. ISSN 1052-8091. Bibcode: 2014MPBu...41..133B. http://www.minorplanet.info/MPB/issues/MPB_41-2.pdf. 
  10. ↑ 10.0 10.1 10.2 Lazzaro, D.; Angeli, C. A.; Carvano, J. M.; Mothé-Diniz, T.; Duffard, R.; Florczak, M. (November 2004). "S3OS2: the visible spectroscopic survey of 820 asteroids". Icarus 172 (1): 179–220. doi:10.1016/j.icarus.2004.06.006. Bibcode: 2004Icar..172..179L. http://sirrah.troja.mff.cuni.cz/yarko-site/tmp/eos/NEW/spectral_type_figure/s3os2.pdf. Retrieved 4 February 2020. 
  11. ↑ "Asteroid 989 Schwassmannia – Proper Elements". AstDyS-2, Asteroids – Dynamic Site. https://newton.spacedys.com/astdys/index.php?pc=1.1.6&n=989. 
  12. ↑ Stephens, Robert D. (April 2014). "Asteroids Observed from CS3: 2013 October-December". Minor Planet Bulletin 41 (2): 92–95. ISSN 1052-8091. Bibcode: 2014MPBu...41...92S. http://www.minorplanet.info/MPB/issues/MPB_41-2.pdf. 
  13. ↑ Behrend, Raoul. "Asteroids and comets rotation curves – (989) Schwassmannia". Geneva Observatory. http://obswww.unige.ch/~behrend/page3cou.html#000989. 

External links



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