Occultation event with (24313) 99YR27, event index number 3491
Regions able to see the event: Australia
Geocentric closest approach at 2026/03/23 09:37:31 UTC
J2000 position of star is 11:38:55.2 +19:06:18
Equinox of date position of star is 11:40:16.9 +18:57:34
Star is 105 degrees from the moon. Moon is 24% illuminated.
Stellar brightness G=15.1, apparent brightess of occulting body is G=16.0
Use an exposure time of 0.45 seconds with the standard RECON-QHY system.
SNR of 5.6 per integration for unocculted signal
Expected flux drop is 69% with SNR of 3.9 for the occulted depth (per occulted point)
Apparent velocity is 17.6 km/sec on the sky relative to the star, or, 18.9 arcsec/hr.
Position angle of asteroid motion is 99.3 degrees
The recommended exposure time corresponds to 7.9 km per image.
The 1-sigma error in the time of the event is 1.5 seconds.
The 1-sigma cross-track error in the shadow position is 26.4 km.
The sky-plane scale is 3360.1 km/arcsec.
Diameter estimates:
41.9 km assuming a 5% albedo, maximum of 2.4 sec for a central chord
17.1 km assuming a 30% albedo, maximum of 1.0 sec for a central chord
Cross-track diameter of 34.6 km used for deployment plan.
Star training set for 24313_99YR27, (2026/03/23 09:38UT) Object RA Dec mag sep mel Regulus 10:09:46.0 +11:50:17 1.3 22.92 89 Denebola 11:50:23.8 +14:25:31 2.1 5.14 109 86 Leo 11:31:50.9 +18:15:54 6.3 2.12 103 PPM 128486 11:44:05.5 +18:05:47 7.2 1.25 106 PPM 128418 11:39:20.7 +19:10:38 9.5 0.31 104 24313_99YR27 11:40:16.9 +18:57:34 16.0 105 Positions are for equinox of date
Star training set for 24313_99YR27, (2026/03/23 09:38UT) Object RA Dec mag sep mel Regulus 10:08:21.9 +11:58:02 1.3 22.92 89 Denebola 11:49:02.7 +14:34:16 2.1 5.14 109 86 Leo 11:30:28.8 +18:24:35 6.3 2.12 103 PPM 128486 11:42:44.0 +18:14:32 7.2 1.25 106 PPM 128418 11:37:59.0 +19:19:21 9.5 0.31 104 24313_99YR27 11:38:55.2 +19:06:18 16.0 105 Positions are for J2000