Occultation event with (9799) Thronium, event index number 1058
Regions able to see the event: SAmericaN
Geocentric closest approach at 2025/06/14 21:54:31 UTC
J2000 position of star is 08:43:07.3 -08:32:01
Equinox of date position of star is 08:44:21.7 -08:37:35
Star is 149 degrees from the moon. Moon is 87% illuminated.
Stellar brightness G=16.0, apparent brightess of occulting body is G=15.6
Use an exposure time of 0.60 seconds with the standard RECON-QHY system.
SNR of 3.1 per integration for unocculted signal
Expected flux drop is 39% with SNR of 1.2 for the occulted depth (per occulted point)
Apparent velocity is 30.7 km/sec on the sky relative to the star, or, 26.0 arcsec/hr.
Position angle of asteroid motion is 356.5 degrees
The recommended exposure time corresponds to 18.4 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 4241.1 km/arcsec.
Diameter estimates:
70.8 km assuming a 5% albedo, aximum of 2.3 sec for a central chord
28.9 km assuming a 30% albedo, maximum of 0.9 sec for a central chord
Cross-track diameter of 70.8 km used for deployment plan.
Star training set for 9799_Thronium, (2025/06/14 21:55UT) Object RA Dec mag sep mel Regulus 10:09:43.5 +11:50:31 1.3 29.48 156 Alphard 09:28:50.3 -08:46:13 2.0 10.99 147 3 Hya 08:36:42.7 -08:04:17 6.2 1.97 150 PPM 191634 08:44:11.5 -08:37:26 8.5 0.04 149 9799_Thronium 08:44:21.7 -08:37:35 15.6 149 Positions are for equinox of date
Star training set for 9799_Thronium, (2025/06/14 21:55UT) Object RA Dec mag sep mel Regulus 10:08:21.9 +11:58:02 1.3 29.48 156 Alphard 09:27:35.2 -08:39:30 2.0 10.99 147 3 Hya 08:35:28.2 -07:58:56 6.2 1.97 150 PPM 191634 08:42:57.1 -08:31:52 8.5 0.04 149 9799_Thronium 08:43:07.3 -08:32:01 15.6 149 Positions are for J2000