Occultation event with (9799) Thronium, event index number 3280
Regions able to see the event: SAmericaS
Geocentric closest approach at 2026/02/21 06:10:29 UTC
J2000 position of star is 10:27:34.3 -30:00:57
Equinox of date position of star is 10:28:46.8 -30:09:00
Star is 138 degrees from the moon. Moon is 16% illuminated.
Stellar brightness G=16.6, apparent brightess of occulting body is G=15.0
Use an exposure time of 1.35 seconds with the standard RECON-QHY system.
SNR of 3.1 per integration for unocculted signal
Expected flux drop is 18% with SNR of 0.6 for the occulted depth (per occulted point)
Apparent velocity is 16.8 km/sec on the sky relative to the star, or, 18.1 arcsec/hr.
Position angle of asteroid motion is 96.6 degrees
The recommended exposure time corresponds to 22.7 km per image.
The 1-sigma error in the time of the event is 1.1 seconds.
The 1-sigma cross-track error in the shadow position is 28.8 km.
The sky-plane scale is 3349.3 km/arcsec.
Diameter estimates:
71.1 km assuming a 5% albedo, maximum of 4.2 sec for a central chord
29.0 km assuming a 30% albedo, maximum of 1.7 sec for a central chord
Cross-track diameter of 68.0 km used for deployment plan.
Star training set for 9799_Thronium, (2026/02/21 06:10UT) Object RA Dec mag sep mel Bet Cru 12:49:16.0 -59:49:52 1.3 37.84 131 Mu Vel 10:47:54.2 -49:33:31 2.8 19.74 132 PPM 257735 10:30:41.6 -29:47:53 5.5 0.54 139 PPM 287646 10:25:01.2 -30:24:58 7.5 0.85 137 PPM 287704 10:28:03.5 -30:12:24 8.6 0.17 138 9799_Thronium 10:28:46.8 -30:09:00 15.0 138 Positions are for equinox of date
Star training set for 9799_Thronium, (2026/02/21 06:10UT) Object RA Dec mag sep mel Bet Cru 12:47:43.1 -59:41:20 1.3 37.84 131 Mu Vel 10:46:46.5 -49:25:13 2.8 19.74 132 PPM 257735 10:29:28.9 -29:39:49 5.5 0.54 139 PPM 287646 10:23:49.1 -30:16:59 7.5 0.85 137 PPM 287704 10:26:51.0 -30:04:22 8.6 0.17 138 9799_Thronium 10:27:34.3 -30:00:57 15.0 138 Positions are for J2000