Astronomy:1919 Clemence

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1919 Clemence
Discovery[1]
Discovered byJ. Gibson
C. U. Cesco
Discovery siteEl Leoncito
Discovery date16 September 1971
Designations
(1919) Clemence
Named afterGerald Clemence
(astronomer)[2]
1971 SA · 1970 EA1
1971 QZ
Minor planet categorymain-belt · (inner)[1]
Hungaria[3][4]
Orbital characteristics[1]
Epoch 4 September 2017 (JD 2458000.5)
Uncertainty parameter 0
Observation arc46.23 yr (16,884 days)
|{{{apsis}}}|helion}}2.1200 AU
|{{{apsis}}}|helion}}1.7522 AU
1.9361 AU
Eccentricity0.0950
Orbital period2.69 yr (984 days)
Mean anomaly286.44°
Mean motion0° 21m 57.24s / day
Inclination19.337°
Longitude of ascending node357.00°
99.880°
Physical characteristics
Dimensions3.238±0.015 km[5]
3.276±0.010[6]
4.95 km (calculated)[4]
Rotation period67.4±0.1 h (revised)[7]
68.5±0.1 h (original)[8]
Geometric albedo0.3 (assumed)[4]
0.686±0.108[6]
0.7103±0.0672[5]
Tholen = X[1]
X[4] · E[5]
B–V = 0.750[1]
U–B = 0.254[1]
Absolute magnitude (H)13.45[1][4][5]


1919 Clemence, provisional designation 1971 SA, is a bright Hungaria asteroid and suspected tumbler from the inner regions of the asteroid belt, approximately 4 kilometers in diameter. It was discovered on 16 September 1971, by American astronomer James Gibson together with Argentine astronomer Carlos Cesco at the Yale-Columbia Southern Station at Leoncito Astronomical Complex in Argentina.[3] It is named after astronomer Gerald Clemence.[2]

Orbit and classification

Clemence is a member of the Hungaria family, which form the innermost dense concentration of asteroids in the Solar System. It orbits the Sun at a distance of 1.8–2.1 AU once every 2 years and 8 months (984 days). Its orbit has an eccentricity of 0.10 and an inclination of 19° with respect to the ecliptic.[1]

Physical characteristics

In the Tholen taxonomic scheme, Clemence is classified as an X-type asteroid.[1] It has also been characterized as an E-type asteroid by the NEOWISE mission.[5]

Rotation period

In March 2005, a rotational lightcurve was obtained by American astronomer Brian Warner at his Palmer Divide Observatory (716) in Colorado. Lightcurve analysis gave a rotation period of 67.4±0.1 hours and a brightness variation of 0.15 magnitude ({{{1}}}).[7] While not being a slow rotator, Clemence has a significantly longer period than most other asteroids, which typically have a spin rate between 2 and 20 hours.

Czech astronomer Petr Pravec from the Ondřejov Observatory believes this may be a tumbling asteroid, yet observations are not sufficient to determine a non-principal axis rotation.[8][9]

Diameter and albedo

According to the surveys carried out by the NEOWISE mission of NASA's Wide-field Infrared Survey Explorer, the asteroid measures 3.2 kilometers in diameter and its surface has an outstandingly high albedo of 0.71,[5] while the Collaborative Asteroid Lightcurve Link assumes an albedo of 0.30 and calculates a somewhat larger diameter of 4.95 kilometers with an absolute magnitude of 13.45.[4]

Naming

This minor planet was named after American astronomer Gerald Maurice Clemence (1908–1974), first scientific director of the United States Naval Observatory and professor of astronomy at the Yale Observatory, known for his work on the theory of the motion of Mars and Mercury, on the system of astronomical constants, and other research in celestial mechanics. He served as president of the American Astronomical Society and of IAU.[2] The official naming citation was published by the Minor Planet Center on 20 February 1976 (M.P.C. 3937).[10]

References

  1. ↑ 1.0 1.1 1.2 1.3 1.4 1.5 1.6 1.7 1.8 "JPL Small-Body Database Browser: 1919 Clemence (1971 SA)". Jet Propulsion Laboratory. https://ssd.jpl.nasa.gov/sbdb.cgi?sstr=2001919. Retrieved 9 June 2017. 
  2. ↑ 2.0 2.1 2.2 Schmadel, Lutz D. (2007). "(1919) Clemence". Dictionary of Minor Planet Names – (1919) Clemence. Springer Berlin Heidelberg. p. 154. doi:10.1007/978-3-540-29925-7_1920. ISBN 978-3-540-00238-3. 
  3. ↑ 3.0 3.1 "1919 Clemence (1971 SA)". Minor Planet Center. https://www.minorplanetcenter.net/db_search/show_object?object_id=1919. Retrieved 19 April 2016. 
  4. ↑ 4.0 4.1 4.2 4.3 4.4 4.5 "LCDB Data for (1919) Clemence". Asteroid Lightcurve Database (LCDB). http://www.minorplanet.info/PHP/generateOneAsteroidInfo.php?AstInfo=1919%7CClemence. Retrieved 19 April 2016. 
  5. ↑ 5.0 5.1 5.2 5.3 5.4 5.5 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. doi:10.1088/0004-637X/741/2/90. Bibcode: 2011ApJ...741...90M. http://adsabs.harvard.edu/cgi-bin/bib_query?bibcode=2011ApJ...741...90M. Retrieved 19 April 2016. 
  6. ↑ 6.0 6.1 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. http://adsabs.harvard.edu/cgi-bin/bib_query?bibcode=2014ApJ...791..121M. Retrieved 21 March 2017. 
  7. ↑ 7.0 7.1 Warner, Brian D.; Stephens, Robert, D.; Harris, Alan W.; Pravec, Petr (October 2009). "A Re-examination of the Lightcurves for Seven Hungaria Asteroids". The Minor Planet Bulletin 36 (4): 176–179. ISSN 1052-8091. Bibcode: 2009MPBu...36..176W. http://adsabs.harvard.edu/cgi-bin/bib_query?bibcode=2009MPBu...36..176W. Retrieved 19 April 2016. 
  8. ↑ 8.0 8.1 Warner, Brian D. (September 2005). "Asteroid lightcurve analysis at the Palmer Divide Observatory - winter 2004-2005". The Minor Planet Bulletin 32 (3): 54–58. ISSN 1052-8091. Bibcode: 2005MPBu...32...54W. http://adsabs.harvard.edu/cgi-bin/bib_query?bibcode=2005MPBu...32...54W. Retrieved 19 April 2016. 
  9. ↑ 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. Bibcode: 2014Icar..233...48P. http://adsabs.harvard.edu/cgi-bin/bib_query?bibcode=2014Icar..233...48P. Retrieved 19 April 2016. 
  10. ↑ 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. 

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