Astronomy:49 Pales

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Short description: Main-belt asteroid
49 Pales
Орбита астероида 49.png
Orbital diagram
Discovery[1]
Discovered byHermann Goldschmidt
Discovery siteParis Observatory
Discovery date19 September 1857
Designations
Designation
(49) Pales
Pronunciation/ˈpeɪliːz/[2]
Named afterPales
Minor planet categoryMain belt[1]
AdjectivesPalian /ˈpeɪliən/; Palilian /pəˈlɪliən/ (adj. only)
Orbital characteristics[3]
Epoch 23 March 2018 (JD 2458200.5)
|{{{apsis}}}|helion}}3.7989 AU
|{{{apsis}}}|helion}}2.4030 AU
3.10093 AU
Eccentricity0.22507
Orbital period1994.51 days (5.46 years)
Mean anomaly169.53°
Inclination3.17°
Longitude of ascending node285.646°
111.146°
Physical characteristics
Dimensions149.80±3.8 km
Mean diameter[4]
Rotation period
  • 20.7057±0.0002 h[5]
  • 20.705±0.002 h[6]
  • 20.704±0.001 h[7]
Albedo0.0597±0.003[4]
Spectral type
C[8]
Absolute magnitude (H)7.8[9]


Pales /ˈpeɪliːz/ (minor planet designation: 49 Pales) is a large, dark main-belt asteroid. It was discovered by German-French astronomer Hermann Goldschmidt on 19 September 1857 from his balcony in Paris.[10] The asteroid is named after Pales, the goddess of shepherds in Roman mythology. Since it was discovered on the same night as 48 Doris, geologist Élie de Beaumont suggested naming the two "The Twins".[11]

The orbit of this asteroid has close to a 2:1 commensurability with the orbit of Jupiter.[12] On 17 January 2000, this minor planet was observed occulting a 9th magnitude star from seven locations. These timed chords across the silhouette allowed an estimate to be made of the object's dimensions,[13] yielding a cross-section of 251 km × 160 km.[14]

Pales has been studied by radar.[15] It has a rotation period of 20.705±0.002 h and a lightcurve with an amplitude of 0.18 mag. The lightcurve shows 4 maxima and 4 minima per cycle, suggesting an irregular shape.[6] The previously accepted period of 10.42 hours with 2 maxima and minima per cycle[16] was proven to be wrong by Pilcher in 2016, showing that correct rotation periods still have not been found for all low-numbered asteroids.[7]

References

  1. ↑ 1.0 1.1 "49 Pales". JPL Small-Body Database. Jet Propulsion Laboratory. https://ssd.jpl.nasa.gov/sbdb.cgi?sstr=49;old=0;orb=0;cov=0;log=0;cad=0#elem. 
  2. ↑ Noah Webster (1884) A Practical Dictionary of the English Language
  3. ↑ "(49) Pales". AstDyS. Italy: University of Pisa. https://hamilton.dm.unipi.it/astdys/index.php?pc=1.1.0&n=49. 
  4. ↑ 4.0 4.1 Tedesco (2004). "Supplemental IRAS Minor Planet Survey (SIMPS)". IRAS-A-FPA-3-RDR-IMPS-V6.0. Planetary Data System. http://www.psi.edu/pds/resource/imps.html. 
  5. ↑ Romeuf, David; Behrend, Raoul (7 January 2016). "Courbes de rotation d'astéroïdes et de comètes" (in fr). https://obswww.unige.ch/~behrend/page1cou.html. 
  6. ↑ 6.0 6.1 Pilcher, Frederick (2017). "Rotation Period Determinations for 49 Pales, 96 Aegle, 106 Dione 375 Ursula, and 576 Emanuela". Minor Planet Bulletin. http://adsabs.harvard.edu/cgi-bin/bib_query?bibcode=2017MPBu...44..249P. 
  7. ↑ 7.0 7.1 Pilcher, Frederick; Benishek, Vladimir; Klinglesmith, Daniel A. (2016). "Rotation Period, Color Indices, and H-G parameters for 49 Pales". Minor Planet Bulletin. http://adsabs.harvard.edu/cgi-bin/bib_query?bibcode=2016MPBu...43..182P. 
  8. ↑ Neese (2005). "Asteroid Taxonomy". EAR-A-5-DDR-TAXONOMY-V5.0. Planetary Data System. http://www.psi.edu/pds/resource/taxonomy.html. 
  9. ↑ Tholen (2007). "Asteroid Absolute Magnitudes". EAR-A-5-DDR-ASTERMAG-V11.0.. Planetary Data System. http://www.psi.edu/pds/resource/astermag.html. 
  10. ↑ "Discovery Circumstances: Numbered Minor Planets (1)–(5000)". IAU: Minor Planet Center. http://www.cfa.harvard.edu/iau/lists/NumberedMPs000001.html. 
  11. ↑ Schmadel, Lutz (2003), Dictionary of minor planet names (fifth ed.), Germany: Springer, p. 19, ISBN 3-540-00238-3, https://books.google.com/books?id=KWrB1jPCa8AC&pg=PA19. 
  12. ↑ Fernández, S.; Beaugé, C. (1988). "The Few Body Problem: Proceedings of the 96th Colloquium of the International Astronomical Union Held in Turku, Finland, June 14–19, 1987". in Valtonen, Mauri. 140. Springer Science & Business Media. pp. 131–133. ISBN 9789027726803. https://books.google.com/books?lr=&id=8Nts26LGlJ8C&pg=PA131. 
  13. ↑ Mizon, R. (April 2000). "'Your friendly local street light'". Journal of the British Astronomical Association 110 (2): 62–63. Bibcode: 2000JBAA..110R..62M. 
  14. ↑ Dunham, D. W. et al. (September 2002). "Asteroidal occultation results multiply helped by Hipparcos". Memorie della Società' Astronomica Italiana 73 (3): 662. Bibcode: 2002MmSAI..73..662D. 
  15. ↑ "Radar-Detected Asteroids and Comets". NASA/JPL Asteroid Radar Research. http://echo.jpl.nasa.gov/asteroids/. 
  16. ↑ Schober, H. J. et al. (April 1979), "Photoelectric photometry and rotation periods of three large and dark asteroids – 49 Pales, 88 Thisbe and 92 Undina", Astronomy and Astrophysics Supplement Series 36: pp. 1–8, Bibcode: 1979A&AS...36....1S. 

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