Occultation event with (11509) Thersilochos, event index number 3395
Regions able to see the event: SAmericaN
Geocentric closest approach at 2026/03/11 01:29:46 UTC
J2000 position of star is 03:34:56.3 +10:13:31
Equinox of date position of star is 03:36:22.0 +10:18:40
Star is 153 degrees from the moon. Moon is 53% illuminated.
Stellar brightness G=15.1, apparent brightess of occulting body is G=15.8
Use an exposure time of 0.45 seconds with the standard RECON-QHY system.
SNR of 5.5 per integration for unocculted signal
Expected flux drop is 64% with SNR of 3.5 for the occulted depth (per occulted point)
Apparent velocity is 25.8 km/sec on the sky relative to the star, or, 24.1 arcsec/hr.
Position angle of asteroid motion is 76.2 degrees
The recommended exposure time corresponds to 11.6 km per image.
The 1-sigma error in the time of the event is 0.2 seconds.
The 1-sigma cross-track error in the shadow position is 29.1 km.
The sky-plane scale is 3857.6 km/arcsec.
Diameter estimates:
55.0 km assuming a 5% albedo, maximum of 2.1 sec for a central chord
22.4 km assuming a 30% albedo, maximum of 0.9 sec for a central chord
Cross-track diameter of 50.0 km used for deployment plan.
Star training set for 11509_Thersilochos, (2026/03/11 01:30UT) Object RA Dec mag sep mel Aldebaran 04:37:25.6 +16:33:35 0.8 16.10 167 Menkar 03:03:39.1 +04:11:27 2.5 10.16 143 6 Tau 03:34:01.1 +09:27:36 5.6 1.03 152 PPM 119160 03:33:53.1 +10:49:33 8.4 0.80 153 PPM 119215 03:37:56.5 +10:16:13 9.1 0.39 153 PPM 119181 03:35:14.6 +10:19:12 10.1 0.28 153 11509_Thersilo 03:36:22.0 +10:18:40 15.8 154 Positions are for equinox of date
Star training set for 11509_Thersilochos, (2026/03/11 01:30UT) Object RA Dec mag sep mel Aldebaran 04:35:55.4 +16:30:29 0.8 16.10 167 Menkar 03:02:16.8 +04:05:21 2.5 10.16 143 6 Tau 03:32:35.9 +09:22:23 5.6 1.03 152 PPM 119160 03:32:27.2 +10:44:19 8.4 0.80 153 PPM 119215 03:36:30.8 +10:11:07 9.1 0.39 153 PPM 119181 03:33:48.9 +10:14:01 10.1 0.28 153 11509_Thersilo 03:34:56.3 +10:13:31 15.8 153 Positions are for J2000