Occultation event with (21601) 98XO89, event index number 3575
Regions able to see the event: SMexico
Geocentric closest approach at 2026/04/04 11:07:11 UTC
J2000 position of star is 13:38:44.8 -30:54:18
Equinox of date position of star is 13:40:14.4 -31:02:16
Star is 16 degrees from the moon. Moon is 94% illuminated.
Stellar brightness G=12.2, apparent brightess of occulting body is G=15.0
Use an exposure time of 0.12 seconds with the standard RECON-QHY system.
SNR of 18.2 per integration for unocculted signal
Expected flux drop is 93% with SNR of 16.9 for the occulted depth (per occulted point)
Apparent velocity is 15.2 km/sec on the sky relative to the star, or, 17.4 arcsec/hr.
Position angle of asteroid motion is 110.2 degrees
The recommended exposure time corresponds to 1.8 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 31.8 km.
The sky-plane scale is 3152.6 km/arcsec.
Diameter estimates:
60.0 km assuming a 5% albedo, maximum of 3.9 sec for a central chord
24.5 km assuming a 30% albedo, maximum of 1.6 sec for a central chord
Cross-track diameter of 54.9 km used for deployment plan.
Star training set for 21601_98XO89, (2026/04/04 11:07UT) Object RA Dec mag sep mel Spica 13:26:34.8 -11:17:51 1.0 19.99 18 Iot Cen 13:22:04.9 -36:51:00 2.8 6.92 23 PPM 291555 13:36:13.6 -33:26:41 6.5 2.55 18 PPM 291662 13:40:53.6 -31:01:06 8.4 0.14 16 21601_98XO89 13:40:14.4 -31:02:16 15.0 16 Positions are for equinox of date
Star training set for 21601_98XO89, (2026/04/04 11:07UT) Object RA Dec mag sep mel Spica 13:25:11.5 -11:09:41 1.0 19.99 18 Iot Cen 13:20:35.1 -36:42:46 2.8 6.92 23 PPM 291555 13:34:43.5 -33:18:40 6.5 2.55 18 PPM 291662 13:39:24.0 -30:53:09 8.4 0.14 16 21601_98XO89 13:38:44.8 -30:54:18 15.0 16 Positions are for J2000