Saturday, the 26 of February, 2022 ~ 20:33:57 UTC (702) Alauda occult UCAC4 422-050240 (mag 13.80)


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  • Legend for each body
    • green line is the central line
    • blue lines show the estimate size
    • red lines the 1-sigma error for the path
Event
  • Date : Saturday, the 26 of February, 2022 ~ 20:33:57 UTC
  • Max duration : 20.20 seconds
  • Shadow velocity : 14.1 km/s
  • Barycenter prediction : Astorb2021
  • Genoide's reference solution : 2021-11-27T08:59:44.734 (Fomc:24.99 mas)
Asteroidal system
  • Name : (702) Alauda
  • Mag : 12.19
  • Geocentric distance : 2.2919 AU
  • Number of Components : 2
  • Component : Alauda
  • Diameter : 202.0 km
  • Max duration : 14.31 sec
  • Component : Pichi_Unem
  • Diameter : 4.0 km
  • Max duration : 0.28 sec
Occulted Star
  • Name : UCAC4 422-050240
  • Used RA   :   09h29m17s1 J2000
  • Used DEC : -05d44m48s7 J2000
  • Mb : 14.15
  • Mv : 13.80
  • Mr : 13.30
  • VizieR - Aladin
Historic
  • 2021-11-29 : Create prediction
Prediction for (702) Alauda system. (wide views)

Alauda

Alauda

Pichi_Unem

Pichi_Unem

Ephemerides from IMCCE

Ephemeris for Alauda

Ephemeris for Pichi_Unem

Ephemeris from Miriade for the date of occultation and geocenter frame. For more specific ephemeris please use the documentation of Miriade.

Orbitography for the (702) Alauda system

Pichi_Unem

Pichi_Unem

Astrometric observations of Pichi_Unem centered on (702) Alauda.
Dot represents one observed position. The vector shows ephemeris position from observed position.

All components on the tangent plane

Propagation of the solutions

We use all the orbits at 1, 2 and 3-σ uncertainties to predict the location of the satellite (relatively to the primary) at the epoch of the occultation. The figure is oriented with North up and East right.

  • The primary is centered at coordinates 0,0, and the arrow shows the direction of the motion of the shadow
  • The black dots show the best orbit at the date of the occultation
  • The green, blue and red dots represent the positions of the satellite within, respectively, 1, 2 and 3-σ uncertainties

Pichi_Unem

Pichi_Unem
This figure displays the orbits of the components of the system at the date of the occultation. Positive x are toward East, and positive y are toward North. Probable positions of the components are displayed with colors depending of its uncertainty: green for 1-σ, blue for 2-σ and red for 3-σ. The largest region where the component should be located is, in kilometers:
  • 1-σ error = 1121 km
  • 2-σ error = 1245 km
  • 3-σ error = 1356 km

Accuracy for timing

The date of the event presented at the top of this page concerns the barycenter of the system. The occultation by the satellite, however, does not occur exactly at this date. If we consider all the 3-σ uncertainties, we can define a time span of the probable occurring of the event. A negative value corresponds to a time prior the date of the main event.

1-σ 2-σ 3-σ
Minimum time offset 9 sec -1 sec -14 sec
Maximum time offset 84 sec 85 sec 86 sec

Accuracy for position

The black arrow shows the direction of the motion of the shadow. The uncertainty of the position of the satellite at the time of the occultation is defined by the clusters of green (1-σ), blue (2-σ) and red (3-σ) dots. The green lines materialize the lower and upper limits of the 1-σ cluster in the direction of the motion of the shadow. The following table shows the uncertainties on the position of the satellite relatively to its best predicted position. A positive value indicates an offset on the position toward : South

1-σ 2-σ 3-σ
Minimum orthogonal projection -554 km -619 km -688 km
Maximum orthogonal projection 566 km 626 km 668 km

More graphics

Contents
  • Orbital solution fitted by Genoid project (Vachier F., Berthier J., Carry B.) IMCCE/CNRS
  • Ephemeris has made available with Miriade Project (Berthier J. & Vachier F.) IMCCE/CNRS
  • Occultation Prediction by Vachier F. using Occult (Occultation Prediction Software by D.Herald)
  • Ephemeris and offset for the barycenter are based on ASTORB (Edward Bowell)