45 Eugenia and Petit-Prince

• Orbit model based on 20 positions taken mostly with VLT-NACO in service observing in Feb. and Mar. 2004, plus additional observations with Keck AO in Dec. 2003 and in Nov. 1998 with PUEO
  • Orbital elements
  • comparison model-observation
  • Observations with NACO (comparison with other binary systems)
• A very small J2 -> a weak precession of the orbit
• Movies

• Pole Solution (110+/-4, -35+/-2) in ecliptic J2000 (close to Lightcurve measurement by Kaasalainen et al., )
• Prograde orbit w.r.t to the spin of the primary, Retrograde orbit w.r.t. revolution around the Sun.
• J2=0.14 +/- 0.01 (1-sigma uncertainty)

Comparison model-observations

Fig 2a: Crosses indicate the positions of Petit-Prince measured on the data (using a Moffat-Gauss profile). The dots are the predicted positions of the orbit model. RMS = 15 mas

Precession of Petit-Prince orbit

J2 ~ 0.14 (clear effect comparing Nov 1998 with Feb-Mar 2004 orbits) Is this J2 is significant? More info soon... Estimate of the Orbit shape at the time of discovery (Nov. 1998) published in Merline et al., 1999

Fig 2b: [bottom] Shape of Petit-Prince orbit on Nov. 1998 at the time of its discovery as published in Merline et al., 1999. Calculated orbits obtained through the model with different J2. The optimal J2=0.03 which is determined in the model gives the best result.

MOVIES

Fig 2c & Movie 2A: Eugenia and Petit-Prince observed from Earth on October 17, 2004 at 3UT. This figure was generated using the pole solution determined through our model, the ellipsoid shape of Kaasalainen et al. confirmed by the AO observations and the orbital elements of Petit-Prince orbit (IMCCE Ephemeris) [click on the image to start the movie] The movie was generated with 1h-step and spanning 4 days

Additional movies covering the entire year 2004 are available on the following link (this is a preliminary result, please contact us if you need a refine prediction)