Occultation event with (9799) Thronium, event index number 1050
Regions able to see the event: SAmericaN
Geocentric closest approach at 2025/06/11 23:31:01 UTC
J2000 position of star is 08:41:05.6 -08:29:58
Equinox of date position of star is 08:42:19.9 -08:35:28
Star is 125 degrees from the moon. Moon is 99% illuminated.
Stellar brightness G=14.9, apparent brightess of occulting body is G=15.5
Use an exposure time of 0.55 seconds with the standard RECON-QHY system.
SNR of 7.4 per integration for unocculted signal
Expected flux drop is 64% with SNR of 4.7 for the occulted depth (per occulted point)
Apparent velocity is 29.8 km/sec on the sky relative to the star, or, 25.4 arcsec/hr.
Position angle of asteroid motion is 356.8 degrees
The recommended exposure time corresponds to 16.4 km per image.
The 1-sigma error in the time of the event is 1.2 seconds.
The 1-sigma cross-track error in the shadow position is 23.7 km.
The sky-plane scale is 4217.0 km/arcsec.
Diameter estimates:
70.8 km assuming a 5% albedo, aximum of 2.4 sec for a central chord
28.9 km assuming a 30% albedo, maximum of 1.0 sec for a central chord
Cross-track diameter of 70.8 km used for deployment plan.
Star training set for 9799_Thronium, (2025/06/11 23:31UT) Object RA Dec mag sep mel Sirius 06:46:16.1 -16:45:09 -1.5 29.42 133 Alphard 09:28:50.3 -08:46:12 2.0 11.49 117 3 Hya 08:36:42.7 -08:04:17 6.2 1.48 127 PPM 191609 08:43:03.7 -08:39:07 8.2 0.19 125 9799_Thronium 08:42:19.9 -08:35:28 15.5 125 Positions are for equinox of date
Star training set for 9799_Thronium, (2025/06/11 23:31UT) Object RA Dec mag sep mel Sirius 06:45:07.9 -16:43:28 -1.5 29.42 133 Alphard 09:27:35.2 -08:39:30 2.0 11.49 117 3 Hya 08:35:28.2 -07:58:56 6.2 1.48 127 PPM 191609 08:41:49.3 -08:33:35 8.2 0.19 125 9799_Thronium 08:41:05.6 -08:29:58 15.5 125 Positions are for J2000