Occultation event with (9857) Hecamede, event index number 3460
Regions able to see the event: Australia,NZ
Geocentric closest approach at 2026/03/18 10:18:39 UTC
J2000 position of star is 11:45:23.2 -23:57:15
Equinox of date position of star is 11:46:42.9 -24:05:59
Star is 152 degrees from the moon. Moon is 1% illuminated.
Stellar brightness G=15.3, apparent brightess of occulting body is G=15.3
Use an exposure time of 0.70 seconds with the standard RECON-QHY system.
SNR of 6.4 per integration for unocculted signal
Expected flux drop is 50% with SNR of 3.2 for the occulted depth (per occulted point)
Apparent velocity is 16.8 km/sec on the sky relative to the star, or, 19.4 arcsec/hr.
Position angle of asteroid motion is 105.1 degrees
The recommended exposure time corresponds to 11.7 km per image.
The 1-sigma error in the time of the event is 1.4 seconds.
The 1-sigma cross-track error in the shadow position is 23.5 km.
The sky-plane scale is 3110.4 km/arcsec.
Diameter estimates:
51.5 km assuming a 5% albedo, maximum of 3.1 sec for a central chord
21.0 km assuming a 30% albedo, maximum of 1.3 sec for a central chord
Cross-track diameter of 49.5 km used for deployment plan.
Star training set for 9857_Hecamede, (2026/03/18 10:19UT) Object RA Dec mag sep mel Spica 13:26:34.7 -11:17:50 1.0 26.94 146 4Gam Crv 12:17:09.5 -17:41:14 2.6 9.57 155 PPM 259265 11:40:19.7 -24:52:05 6.4 1.64 152 PPM 259371 11:44:55.8 -24:21:40 8.4 0.48 152 PPM 259396 11:45:54.6 -24:09:44 9.8 0.19 152 9857_Hecamede 11:46:42.9 -24:05:59 15.3 152 Positions are for equinox of date
Star training set for 9857_Hecamede, (2026/03/18 10:19UT) Object RA Dec mag sep mel Spica 13:25:11.5 -11:09:41 1.0 26.94 146 4Gam Crv 12:15:48.1 -17:32:30 2.6 9.57 155 PPM 259265 11:39:00.5 -24:43:22 6.4 1.64 152 PPM 259371 11:43:36.3 -24:12:56 8.4 0.48 152 PPM 259396 11:44:35.0 -24:00:59 9.8 0.19 152 9857_Hecamede 11:45:23.2 -23:57:15 15.3 152 Positions are for J2000