Occultation event with (9799) Thronium, event index number 1372
Regions able to see the event: SAmericaN
Geocentric closest approach at 2025/10/15 09:05:29 UTC
J2000 position of star is 10:19:26.6 -17:56:47
Equinox of date position of star is 10:20:41.2 -18:04:35
Star is 42 degrees from the moon. Moon is 33% illuminated.
Stellar brightness G=16.2, apparent brightess of occulting body is G=15.6
Use an exposure time of 0.70 seconds with the standard RECON-QHY system.
SNR of 3.0 per integration for unocculted signal
Expected flux drop is 36% with SNR of 1.1 for the occulted depth (per occulted point)
Apparent velocity is 36.8 km/sec on the sky relative to the star, or, 30.3 arcsec/hr.
Position angle of asteroid motion is 127.9 degrees
The recommended exposure time corresponds to 25.8 km per image.
The 1-sigma error in the time of the event is 0.8 seconds.
The 1-sigma cross-track error in the shadow position is 14.4 km.
The sky-plane scale is 4380.2 km/arcsec.
Diameter estimates:
71.1 km assuming a 5% albedo, aximum of 1.9 sec for a central chord
29.0 km assuming a 30% albedo, maximum of 0.8 sec for a central chord
Cross-track diameter of 68.0 km used for deployment plan.
Star training set for 9799_Thronium, (2025/10/15 09:05UT) Object RA Dec mag sep mel Regulus 10:09:44.6 +11:50:25 1.3 30.04 18 Alphard 09:28:51.3 -08:46:18 2.0 15.65 29 42Mu Hya 10:27:20.4 -16:58:07 3.8 1.93 42 PPM 222828 10:22:22.5 -18:06:57 6.7 0.40 43 PPM 222791 10:21:09.5 -17:58:03 9.4 0.16 42 9799_Thronium 10:20:41.2 -18:04:35 15.6 43 Positions are for equinox of date
Star training set for 9799_Thronium, (2025/10/15 09:05UT) Object RA Dec mag sep mel Regulus 10:08:21.9 +11:58:02 1.3 30.04 18 Alphard 09:27:35.2 -08:39:30 2.0 15.65 29 42Mu Hya 10:26:05.2 -16:50:13 3.8 1.93 42 PPM 222828 10:21:07.9 -17:59:07 6.7 0.40 43 PPM 222791 10:19:54.9 -17:50:14 9.4 0.16 42 9799_Thronium 10:19:26.6 -17:56:47 15.6 42 Positions are for J2000