Occultation event with (9799) Thronium, event index number 3143
Regions able to see the event: SAfrica
Geocentric closest approach at 2026/01/13 21:29:33 UTC
J2000 position of star is 10:44:12.3 -28:41:12
Equinox of date position of star is 10:45:26.2 -28:49:26
Star is 66 degrees from the moon. Moon is 21% illuminated.
Stellar brightness G=14.7, apparent brightess of occulting body is G=15.2
Use an exposure time of 0.65 seconds with the standard RECON-QHY system.
SNR of 10.0 per integration for unocculted signal
Expected flux drop is 62% with SNR of 6.2 for the occulted depth (per occulted point)
Apparent velocity is 14.2 km/sec on the sky relative to the star, or, 14.3 arcsec/hr.
Position angle of asteroid motion is 34.5 degrees
The recommended exposure time corresponds to 9.2 km per image.
The 1-sigma error in the time of the event is 1.3 seconds.
The 1-sigma cross-track error in the shadow position is 29.7 km.
The sky-plane scale is 3579.9 km/arcsec.
Diameter estimates:
71.1 km assuming a 5% albedo, maximum of 5.0 sec for a central chord
29.0 km assuming a 30% albedo, maximum of 2.0 sec for a central chord
Cross-track diameter of 68.0 km used for deployment plan.
Star training set for 9799_Thronium, (2026/01/13 21:30UT) Object RA Dec mag sep mel Bet Cru 12:49:15.7 -59:49:50 1.3 37.40 46 Mu Vel 10:47:53.9 -49:33:29 2.8 20.74 61 PPM 257903 10:37:56.2 -27:47:31 6.5 1.95 67 PPM 258065 10:44:41.7 -29:12:06 8.0 0.41 66 PPM 258081 10:45:37.2 -28:40:02 9.4 0.16 66 9799_Thronium 10:45:26.2 -28:49:26 15.2 65 Positions are for equinox of date
Star training set for 9799_Thronium, (2026/01/13 21:30UT) Object RA Dec mag sep mel Bet Cru 12:47:43.1 -59:41:20 1.3 37.40 46 Mu Vel 10:46:46.5 -49:25:13 2.8 20.74 61 PPM 257903 10:36:42.6 -27:39:23 6.5 1.95 67 PPM 258065 10:43:27.9 -29:03:53 8.0 0.41 66 PPM 258081 10:44:23.2 -28:31:48 9.4 0.16 66 9799_Thronium 10:44:12.3 -28:41:12 15.2 66 Positions are for J2000