Occultation event with (4834) Thoas, event index number 3626
Regions able to see the event: SAfrica
Geocentric closest approach at 2026/04/13 21:01:31 UTC
J2000 position of star is 12:34:38.8 +32:39:02
Equinox of date position of star is 12:35:56.2 +32:30:21
Star is 144 degrees from the moon. Moon is 16% illuminated.
Stellar brightness G=15.0, apparent brightess of occulting body is G=14.4
Use an exposure time of 1.05 seconds with the standard RECON-QHY system.
SNR of 9.7 per integration for unocculted signal
Expected flux drop is 38% with SNR of 3.7 for the occulted depth (per occulted point)
Apparent velocity is 15.8 km/sec on the sky relative to the star, or, 17.2 arcsec/hr.
Position angle of asteroid motion is 84.4 degrees
The recommended exposure time corresponds to 16.6 km per image.
The 1-sigma error in the time of the event is 1.1 seconds.
The 1-sigma cross-track error in the shadow position is 34.7 km.
The sky-plane scale is 3310.2 km/arcsec.
Diameter estimates:
89.1 km assuming a 5% albedo, maximum of 5.6 sec for a central chord
36.4 km assuming a 30% albedo, maximum of 2.3 sec for a central chord
Cross-track diameter of 72.3 km used for deployment plan.
Star training set for 4834_Thoas, (2026/04/13 21:02UT) Object RA Dec mag sep mel Arcturus 14:16:51.7 +19:02:49 0.0 26.30 126 Denebola 11:50:23.9 +14:25:30 2.1 20.84 161 PPM 076567 12:34:56.4 +33:06:10 5.4 0.63 143 PPM 076537 12:32:48.4 +32:52:10 7.5 0.75 144 PPM 076585 12:36:35.4 +32:54:13 9.4 0.42 143 PPM 076580 12:36:26.2 +32:40:07 11.2 0.19 143 4834_Thoas 12:35:56.2 +32:30:21 14.4 143 Positions are for equinox of date
Star training set for 4834_Thoas, (2026/04/13 21:02UT) Object RA Dec mag sep mel Arcturus 14:15:37.7 +19:10:06 0.0 26.30 126 Denebola 11:49:02.7 +14:34:16 2.1 20.84 161 PPM 076567 12:33:39.0 +33:14:50 5.4 0.63 143 PPM 076537 12:31:30.8 +33:00:52 7.5 0.75 144 PPM 076585 12:35:18.1 +33:02:53 9.4 0.42 143 PPM 076580 12:35:08.9 +32:48:47 11.2 0.19 143 4834_Thoas 12:34:38.8 +32:39:02 14.4 144 Positions are for J2000