Astroblog: South African Astronomers! A Chance to Catch the Ringed Asteroid Chariklo with an Occultation (and a Celestia File!)

Friday, April 04, 2014

South African Astronomers! A Chance to Catch the Ringed Asteroid Chariklo with an Occultation (and a Celestia File!)

Just in case you missed it, one of the big astronomical news items in late March was the discovery that asteroid Chariklo has rings. While all the giant planets have rings, it was astonishing that such a small body would have a ring system. You can read the actual paper here.

The ring system was discovered when the asteroid occulted (passed in front of) a star, dips in the stars light before and after the asteroid itself dimmed the star revealed their presence. This was how the rings of Uranus were discovered in 1997.

Chart of the occulation path of asteroid Chariklo

On 29th of April Chariklo will again occult a star, this time a 12th magnitude star. This will be seen from South Africa at 23h13min UTC.

This will be an excellent opportunity for amateur and professional observers to study this astonishing ring system.

Full observing instruction, observing charts and more can be found at the special IOTA Chariklo observing site.

In honour of this special occasion I have made a Celestia file of Chariklo, I've added rings, based on Saturn's rings (using Uranus's rings makes it too dim). As usual, copy the data here to a plain text file (10199Chariklo.ssc) and copy the file to the Celestia extras folder.

============================10199Chariklo.ssc=============================
"10199 Chariklo:Chariklo:1997 CU26" "Sol"

#Asteroid with rings http://www.eso.org/public/archives/releases/sciencepapers/eso1410/eso1410a.pdf
#Data from MPC http://cfa-www.harvard.edu/iau/MPEph/MPEph.html
#Epoch 2014 May 23.0 TT = JDT 2456800.5                  MPC
#M 60.13106              (2000.0)            P               Q
#n   0.01576192     Peri. 241.60043     -0.93692798     +0.06833546             T = 2452985.54248 JDT
#a 15.7542102      Node   300.37989     +0.14092715     -0.82359414             q =    13.0508682
#e   0.1715949      Incl.   23.41167     -0.31985232     -0.56304792
#P 62.5            H    6.6           G   0.15           U   0
#From 533 observations at 16 oppositions, 1988-2009, mean residual 0".46.

{
   Class "asteroid"
   Mesh   "ky26.cmod"
   Texture "asteroid.jpg"
   Radius 129.6 # maximum semi-axis
   MeshCenter [ -0.000718 -0.000099 0.000556 ]

   InfoURL "http://en.wikipedia.org/wiki/10199_Chariklo"

   EllipticalOrbit
   {
   Epoch                  2456800.5      # Epoch 2014 May 23.0 TT = JDT 2456800.5
   Period                 62.5           # P
   SemiMajorAxis          15.7542102     # a
   Eccentricity           0.1715949      # e
   Inclination            23.41167       # Incl.
   AscendingNode          300.37989      # Node
   ArgOfPericenter       241.60043       # Peri
        PericenterDistance      13.0508682    # q
        MeanAnomaly             60.13106      # M
   }

   RotationPeriod 0.9 #Guess

   Albedo 0.048        #Based on Chiron

   Rings {
       Inner 400
       Outer 450
       Texture "saturn-rings.png"
   }

}======================================================