Occultation event with (9799) Thronium, event index number 948
Regions able to see the event: Australia
Geocentric closest approach at 2025/05/05 10:34:01 UTC
J2000 position of star is 08:20:09.8 -08:58:50
Equinox of date position of star is 08:21:23.4 -09:03:43
Star is 34 degrees from the moon. Moon is 59% illuminated.
Stellar brightness G=16.1, apparent brightess of occulting body is G=15.4
Use an exposure time of 1.00 seconds with the standard RECON-QHY system.
SNR of 4.2 per integration for unocculted signal
Expected flux drop is 35% with SNR of 1.5 for the occulted depth (per occulted point)
Apparent velocity is 16.9 km/sec on the sky relative to the star, or, 15.8 arcsec/hr.
The recommended exposure time corresponds to 16.9 km per image.
The 1-sigma error in the time of the event is 2.0 seconds.
The 1-sigma cross-track error in the shadow position is 24.9 km.
The sky-plane scale is 3861.4 km/arcsec.
Diameter estimates:
70.8 km assuming a 5% albedo, aximum of 4.2 sec for a central chord
28.9 km assuming a 30% albedo, maximum of 1.7 sec for a central chord
Cross-track diameter of 70.8 km used for deployment plan.
Star training set for 9799_Thronium, (2025/05/05 10:34UT) Object RA Dec mag sep mel Sirius 06:46:15.8 -16:45:09 -1.5 24.40 57 15Rho Pup 08:08:37.4 -24:22:44 2.8 15.62 48 PPM 219950 08:20:27.9 -10:14:47 6.3 1.21 35 PPM 191229 08:22:17.6 -08:57:54 7.7 0.24 34 9799_Thronium 08:21:23.4 -09:03:43 15.4 34 Positions are for equinox of date
Star training set for 9799_Thronium, (2025/05/05 10:34UT) Object RA Dec mag sep mel Sirius 06:45:07.9 -16:43:28 -1.5 24.40 57 15Rho Pup 08:07:32.5 -24:18:14 2.8 15.62 48 PPM 219950 08:19:15.0 -10:09:56 6.3 1.21 35 PPM 191229 08:21:04.0 -08:53:00 7.7 0.24 34 9799_Thronium 08:20:09.8 -08:58:50 15.4 34 Positions are for J2000