49 Pales

49 Pales
Orbital diagram
Discovery[1]
Discovered byHermann Goldschmidt
Discovery siteParis Observatory
Discovery date19 September 1857
Designations
Designation
(49) Pales
Pronunciation/ˈpeɪliːz/[2]
Named after
Pales
Main belt[1]
AdjectivesPalian /ˈpeɪliən/; Palilian /pəˈlɪliən/ (adj. only)
Orbital characteristics[3]
Epoch 23 March 2018 (JD 2458200.5)
Aphelion3.7989 AU
Perihelion2.4030 AU
3.10093 AU
Eccentricity0.22507
1994.51 days (5.46 years)
169.53°
Inclination3.17°
285.646°
111.146°
Physical characteristics
Dimensions149.80±3.8 km
Mean diameter[4]
Mass2.69×1018 kg[5]
  • 20.7057±0.0002 h[6]
  • 20.705±0.002 h[7]
  • 20.704±0.001 h[8]
Albedo0.0597±0.003[4]
Spectral type
C[9]
7.8[10]

49 Pales (/ˈpeɪliːz/) 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.[11] 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".[12]

The orbit of this asteroid has close to a 2:1 commensurability with the orbit of Jupiter.[13] 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,[14] yielding a cross-section of 251 km × 160 km.[15]

Pales has been studied by radar.[16] 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.[7] The previously accepted period of 10.42 hours with 2 maxima and minima per cycle[17] was proven to be wrong by Pilcher in 2016, showing that correct rotation periods still have not been found for all low-numbered asteroids.[8]

  1. ^ a b "49 Pales". JPL Small-Body Database. Jet Propulsion Laboratory. Retrieved 26 June 2018.
  2. ^ Noah Webster (1884) A Practical Dictionary of the English Language
  3. ^ "(49) Pales". AstDyS. Italy: University of Pisa. Archived from the original on 27 February 2012. Retrieved 29 December 2008.
  4. ^ a b Cite error: The named reference SIMPS was invoked but never defined (see the help page).
  5. ^ Jim Baer (2008). "Recent Asteroid Mass Determinations". Personal Website. Archived from the original on 29 January 2009. Retrieved 29 December 2008.
  6. ^ Cite error: The named reference Behrend 2016web was invoked but never defined (see the help page).
  7. ^ a b Cite error: The named reference Pilcher2017 was invoked but never defined (see the help page).
  8. ^ a b Cite error: The named reference Pilcher2016 was invoked but never defined (see the help page).
  9. ^ Cite error: The named reference Neese was invoked but never defined (see the help page).
  10. ^ Cite error: The named reference Tholen was invoked but never defined (see the help page).
  11. ^ "Discovery Circumstances: Numbered Minor Planets (1)–(5000)". IAU: Minor Planet Center. Archived from the original on 2 February 2009. Retrieved 29 December 2008.
  12. ^ Cite error: The named reference Schmadel2003 was invoked but never defined (see the help page).
  13. ^ Cite error: The named reference Fernández1987 was invoked but never defined (see the help page).
  14. ^ Cite error: The named reference Mizon2000 was invoked but never defined (see the help page).
  15. ^ Cite error: The named reference Dunham2002 was invoked but never defined (see the help page).
  16. ^ Cite error: The named reference detected was invoked but never defined (see the help page).
  17. ^ Cite error: The named reference Schober1979 was invoked but never defined (see the help page).