Occultation by (3220) Murayama, 2025-01-28

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Occultation map

prediction map

(*) The blue dots are separated by a one-minute interval and the big blue dot corresponds to the nominal occultation time (which is the geocentric closest approach).
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Occultation circumstances

Occultation event id 47747
Date at closest approach Tue. 28 Jan. 2025 19:02:53
Star position (ICRF) 02 58 48.3323 +24 18 43.111
C/A 2.631 arcsec
P/A 345.86 °
velocity 15.00 km/s
Geocentric distance Δ 1.4229 au
Star G magnitude 9.6
Magnitude drop 7.2
Max occultation duration (main body) 0.3 sec
Moon distance to the object 110.2°
Fraction of illuminated Moon 0.8 %
Solar elongation 100.4°
Prediction source JPL56
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Star & Object data

Occulted star informations

Star source ID 110326547215007488
Stellar catalogue GaiaDR3
Star astrometric position in catalogue (ICRF) 02 58 48.3372 +24 18 43.063
Star astrometric position with proper motion (ICRF) 02 58 48.3323 +24 18 43.111
Star apparent position (date) 03 00 16.2903 +24 24 49.452
Proper motion μRA* = (-7.3 ± 0.0)mas/yr; μDEC = (5.3 ± 0.0) mas/yr
Source of proper motion GaiaDR3
Uncertainty in the star position RA* = 0.2 mas; DEC= 0.2 mas
G mag* 9.3
J mag* 8.4
H mag* 6.2
RP magnitude (source: GaiaDR3) 8.7
BP magnitude (source: GaiaDR3) 10.4
J magnitude (source: 2MASS) 7.4
H magnitude (source: 2MASS) 6.5
K magnitude (source: 2MASS) 6.3
RUWE (source: Gaia) 1.15

Main Object informations (primary)

(ID) Object (3220) Murayama
Primary diameter 5.1 km
Uncertainty in primary diameter 0.80 km
Apparent primary diameter 4.9 mas
Semi-major Axis 2.23 au
Object astrometric position (ICRF) 02 58 48.2851 +24 18 45.661
Object apparent position (date) 03 00 16.2433 +24 24 52.003
Apparent magnitude 16.7
Source Gaiamoons
Binarity nature Suspected binary
Priority index 2

Binary system estimated informations (satellite)

Estimated separation 1145.92 km
Uncertainty in separation 1128.26 km
Estimated separation 214645.95 km
Uncertainty in separation 214628.29 km
Diameter (sol° 1)2.16 km
Uncertainty in diameter (sol° 1)0.34 km
Max occultation duration (sol° 1)0.14 s
Diameter (sol° 2)4.21 km
Uncertainty in diameter (sol° 2)1.13 km
Max occultation duration (sol° 2)0.28 s
Wobble Period26.31 h
Uncertainty in wobble period9.25 h
SNR<1
(1)Due to GAIA’s 6-hour rotation and its two telescopes, each asteroid is observed discontinuously. Combining all sparse observations allows multiple possible solutions for the same object that we call window.
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Sky map (Aladin)

link to sky-map
For declination above -25 °, Pan-STARRS survey is displayed by default whereas below -25 °, DSS is displayed.
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Interactive Map

Observation advice
To be able to observe the asteroid satellite, we recommend, if the satellite is in the path of the primary body, that you start recording your observations preferentially around 15min beforehand.

Interactive map legend
  • Large blue lines : Primary body's limits of the nominal prediction.
  • Large dotted blue line : Centrality of the nominal prediction, which is the center of mass of the system.
  • Large red lines : Area where the satellite can be at the time of occultation, which is the largest acceptable estimated separation limit.
  • White area : Represents the daylight part on Earth and the blue area represents the region on Earth where the object is not visible.
  • Shadow at nominal time is displayed, the brighter part represents the uncertainty in the body's radius.
  • Sun symbol indicates the place where the Sun is at the zenith at the nominal time.
  • Star symbol indicates the place where the occulted star is at the zenith at the nominal time.
  • Grey zone : Night area withour occultation.

By clicking on one place, you will have an infobox with :
  • Coordinates: Longitude and latitude;
  • ρ and Δd: Impact parameter (i.e. projected distance to the central line) and σ distance; Δd is (ρ-r)/σd where r is the object radius and σd is the uncertainty in distance;
  • Mid time: Mid time of the occultation at the selected place
  • Expected duration (main body): Expected duration of the occultation of the main body at the selected place
  • Max expected duration (satellite): Expected maximum duration of the occultation of the satellite at the selected place, the two values corresponds to the two possibles solutions for the satellite diameter
  • Object elevation: Object's elevation above the horizon at the selected place at the mid time
  • Airmass: Amount of Earth's atmosphere that starlight passes through to reach a telescope
  • Sun and Moon elevation: Sun's and Moon's elevation above the horizon at the selected place at the mid time
Once the place selected, the shadow at mid-time of the occultation for the location is displayed. The chord for your location appears in as a green dotted line. Sun and star symbols as well as the night area and area where the star is not visible are ajusted at the mid-time of your location.