Occultation event with (15527) 99YY2, event index number 3432
Regions able to see the event: US,SAfrica
Geocentric closest approach at 2026/03/15 02:38:13 UTC
J2000 position of star is 11:04:45.0 +02:45:58
Equinox of date position of star is 11:06:05.9 +02:37:28
Star is 139 degrees from the moon. Moon is 17% illuminated.
Stellar brightness G=13.5, apparent brightess of occulting body is G=16.3
Use an exposure time of 0.16 seconds with the standard RECON-QHY system.
SNR of 9.6 per integration for unocculted signal
Expected flux drop is 93% with SNR of 9.0 for the occulted depth (per occulted point)
Apparent velocity is 19.8 km/sec on the sky relative to the star, or, 19.5 arcsec/hr.
Position angle of asteroid motion is 125.0 degrees
The recommended exposure time corresponds to 3.2 km per image.
The 1-sigma error in the time of the event is 1.0 seconds.
The 1-sigma cross-track error in the shadow position is 26.3 km.
The sky-plane scale is 3646.9 km/arcsec.
Diameter estimates:
38.7 km assuming a 5% albedo, maximum of 2.0 sec for a central chord
15.8 km assuming a 30% albedo, maximum of 0.8 sec for a central chord
Cross-track diameter of 36.4 km used for deployment plan.
Star training set for 15527_99YY2, (2026/03/15 02:38UT) Object RA Dec mag sep mel Regulus 10:09:45.9 +11:50:17 1.3 16.72 156 Denebola 11:50:23.7 +14:25:32 2.1 16.09 134 58 Leo 11:01:54.8 +03:28:35 4.8 1.35 141 PPM 157447 11:03:38.7 +02:02:53 7.8 0.84 140 PPM 157503 11:07:13.2 +02:54:44 9.9 0.40 139 PPM 157482 11:06:05.2 +02:20:45 10.6 0.28 139 15527_99YY2 11:06:05.9 +02:37:28 16.3 139 Positions are for equinox of date
This table contains the target star visibility for registered US sites that are relevant for this occultation. This list has been filtered to only those sites that can see the field and are within range of the shadow given the uncertainties. The observing time range has been calculated to cover the time of the event at each site with allowances for the event timing uncertainty plus time for obtaining a pre and post event baseline lightcurve. This set of stations has a 0.6 % chance of getting at least one chord. There is a 0.0% chance of 2 or more chords assuming clear weather for all.
| Site Name | Site mid-time (UT) |
Sun alt (deg) |
Sky | Moon | Star alt (deg) |
Star az (deg) |
Target | Observing Time | Xtrack (km) |
Prob |
|---|---|---|---|---|---|---|---|---|---|---|
| Patrick | 02:42:50 | -19.5 | Dark | Down | 26.8 | 106.7 | Up | 02:38:36-02:44:36 | 182.1 | 0.000 | George/Scottsdale | 02:43:00 | -15.0 | AT | Down | 22.6 | 102.4 | Up | 02:38:34-02:44:34 | -81.9 | 0.006 |
Star training set for 15527_99YY2, (2026/03/15 02:38UT) Object RA Dec mag sep mel Regulus 10:08:21.9 +11:58:02 1.3 16.72 156 Denebola 11:49:02.7 +14:34:16 2.1 16.09 134 58 Leo 11:00:33.7 +03:37:02 4.8 1.35 141 PPM 157447 11:02:17.8 +02:11:22 7.8 0.84 140 PPM 157503 11:05:52.2 +03:03:15 9.9 0.40 139 PPM 157482 11:04:44.3 +02:29:15 10.6 0.28 139 15527_99YY2 11:04:45.0 +02:45:58 16.3 139 Positions are for J2000