Occultation event with (9799) Thronium, event index number 3550
Regions able to see the event: SAmericaN,SAmericaS
Geocentric closest approach at 2026/03/31 07:06:30 UTC
J2000 position of star is 10:08:57.9 -27:52:29
Equinox of date position of star is 10:10:10.0 -28:00:15
Star is 36 degrees from the moon. Moon is 97% illuminated.
Stellar brightness G=13.7, apparent brightess of occulting body is G=15.0
Use an exposure time of 0.20 seconds with the standard RECON-QHY system.
SNR of 9.2 per integration for unocculted signal
Expected flux drop is 76% with SNR of 7.0 for the occulted depth (per occulted point)
Apparent velocity is 16.3 km/sec on the sky relative to the star, or, 17.4 arcsec/hr.
Position angle of asteroid motion is 139.4 degrees
The recommended exposure time corresponds to 3.3 km per image.
The 1-sigma error in the time of the event is 2.1 seconds.
The 1-sigma cross-track error in the shadow position is 7.1 km.
The sky-plane scale is 3361.0 km/arcsec.
Diameter estimates:
71.1 km assuming a 5% albedo, maximum of 4.4 sec for a central chord
29.0 km assuming a 30% albedo, maximum of 1.8 sec for a central chord
Cross-track diameter of 68.0 km used for deployment plan.
Star training set for 9799_Thronium, (2026/03/31 07:07UT) Object RA Dec mag sep mel Adhara 06:59:39.5 -29:00:34 1.5 41.57 70 Lam Vel 09:08:57.8 -43:32:22 2.2 19.82 55 PPM 257358 10:14:32.0 -27:09:34 6.4 1.28 34 PPM 257276 10:10:31.1 -28:01:46 8.5 0.08 35 9799_Thronium 10:10:10.0 -28:00:15 15.0 35 Positions are for equinox of date
Star training set for 9799_Thronium, (2026/03/31 07:07UT) Object RA Dec mag sep mel Adhara 06:58:37.6 -28:58:19 1.5 41.57 70 Lam Vel 09:07:59.7 -43:25:57 2.2 19.82 55 PPM 257358 10:13:19.3 -27:01:43 6.4 1.28 34 PPM 257276 10:09:18.9 -27:54:00 8.5 0.08 35 9799_Thronium 10:08:57.9 -27:52:29 15.0 36 Positions are for J2000