Occultation event with (9799) Thronium, event index number 3438
Regions able to see the event: Australia
Geocentric closest approach at 2026/03/15 15:20:40 UTC
J2000 position of star is 10:15:33.5 -29:05:51
Equinox of date position of star is 10:16:45.5 -29:13:43
Star is 129 degrees from the moon. Moon is 13% illuminated.
Stellar brightness G=13.7, apparent brightess of occulting body is G=14.9
Use an exposure time of 0.20 seconds with the standard RECON-QHY system.
SNR of 9.0 per integration for unocculted signal
Expected flux drop is 75% with SNR of 6.7 for the occulted depth (per occulted point)
Apparent velocity is 17.4 km/sec on the sky relative to the star, or, 18.8 arcsec/hr.
Position angle of asteroid motion is 121.5 degrees
The recommended exposure time corresponds to 3.5 km per image.
The 1-sigma error in the time of the event is 1.8 seconds.
The 1-sigma cross-track error in the shadow position is 18.0 km.
The sky-plane scale is 3324.6 km/arcsec.
Diameter estimates:
71.1 km assuming a 5% albedo, maximum of 4.1 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, (2026/03/15 15:21UT) Object RA Dec mag sep mel Bet Cru 12:49:16.3 -59:49:53 1.3 39.90 89 Lam Vel 09:08:57.7 -43:32:22 2.2 19.70 117 PPM 257470 10:19:19.8 -29:07:26 5.3 0.57 129 PPM 257425 10:17:31.0 -29:06:36 8.1 0.20 129 9799_Thronium 10:16:45.5 -29:13:43 14.9 128 Positions are for equinox of date
Star training set for 9799_Thronium, (2026/03/15 15:21UT) Object RA Dec mag sep mel Bet Cru 12:47:43.1 -59:41:20 1.3 39.90 89 Lam Vel 09:07:59.7 -43:25:57 2.2 19.70 117 PPM 257470 10:18:07.6 -28:59:31 5.3 0.57 129 PPM 257425 10:16:18.9 -28:58:43 8.1 0.20 129 9799_Thronium 10:15:33.5 -29:05:51 14.9 129 Positions are for J2000