Occultation by Patroclus (2019-03-18)


Occultation map

prediction map

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Information about the map:

  • The straight and continue lines are the shadow limits considering the estimated radius; when the shadow crosses the Earth's surface, the path is projected on the Earth;
  • Each blue dot is spaced by one minute and the big blue dot corresponds to the nominal occultation time (which is the geocentric closest approach);
  • The arrow shows the direction of the shadow motion;
  • The 1-σ precision along the path is represented by the red dotted line;
  • The star G* and RP* are the G (from Gaia) and RP (red photometer from GaiaDR2) magnitudes, normalized to a body moving at 20km/s in order to enhance very slow events;
  • The body offset is at the upper right corner, if JPL ephemeris is used;
  • Areas in dark grey correspond to full night (Sun elevation below -18 degrees) and areas in light grey correspond to twilight (Sun elevation between -18 and 0 degrees) while daytime is in white;
  • Be careful, the dates are from the moment of the event in Universal Time, the night of the event may begin at the date before.

Occultation circumstances

Date Mon. 18 Mar. 2019 01:39:23
Star position (ICRF) 13 10 51.4716 +09 05 18.198
C/A 0.311 arcsec
P/A 198.71 °
velocity -17.88 km/s
Geocentric distance Δ 4.9677 au
G mag* 11.1
RP mag* 10.3
H mag* 8.7
Magnitude drop 4.7
Uncertainty in time 4.6 sec
Uncertainty in C/A 18.8 mas
Uncertainty in projected distance 67.7 km
Probability of occultation on centrality 69.9%
Maximum duration 7.8 sec
Moon distance to the object 58.7°
Fraction of illuminated Moon 87.1 %
Solar elongation 157.8°

Star & Object data

Occulted star

Star source ID 3732454364091001216
Stellar catalogue GAIADR2
Star astrometric position in catalogue (ICRF) 13 10 51.4755 +09 05 18.241
Star astrometric position with proper motion (ICRF) 13 10 51.4716 +09 05 18.198
Star apparent position (date) 13 11 49.5110 +08 59 09.385
Proper motion μRA* = (-15.8 ± 0.1)mas/yr; μDEC = (-11.8 ± 0.1) mas/yr
Source of proper motion GAIADR2
Uncertainty in the star position RA* = 0.3 mas; DEC= 0.2 mas
G magnitude 11.2
RP magnitude (source: GaiaDR2) 10.5
BP magnitude (source: GaiaDR2) 11.9
J magnitude (source: 2MASS) 9.4
H magnitude (source: 2MASS) 8.8
K magnitude (source: 2MASS) 8.6

Objet

Object (617) Patroclus
Diameter 140.0 km
Apparent diameter 38.9 mas
Object astrometric position (ICRF) 13 10 51.4648 +09 05 17.903
Object apparent position (date) 13 11 49.5042 +08 59 09.090
Uncertainty in position RA* = 21.5mas DEC = 20.4mas
Apparent magnitude 15.9
Ephemeris NIMAv1
Dynamic class(1) trojan
Semi major axis 5.2 au
Eccentricity 0.138
Inclination 22.0°
Perihelion 4.5 au
Aphelion 5.9 au
(1) Data from the johnston archive list.

Sky map (Aladin)

link to sky-map