Occultation event with (11509) Thersilochos, event index number 5162
Regions able to see the event: Australia
Geocentric closest approach at 2026/12/10 14:53:36 UTC
J2000 position of star is 05:59:13.9 +05:11:43
Equinox of date position of star is 06:00:40.0 +05:11:43
Star is 157 degrees from the moon. Moon is 2% illuminated.
Stellar brightness G=16.5, apparent brightess of occulting body is G=15.2
Use an exposure time of 1.10 seconds with the standard RECON-QHY system.
SNR of 3.1 per integration for unocculted signal
Expected flux drop is 23% with SNR of 0.7 for the occulted depth (per occulted point)
Apparent velocity is 17.7 km/sec on the sky relative to the star, or, 20.2 arcsec/hr.
Position angle of asteroid motion is 76.8 degrees
The recommended exposure time corresponds to 19.5 km per image.
The 1-sigma error in the time of the event is 0.1 seconds.
The 1-sigma cross-track error in the shadow position is 29.3 km.
The sky-plane scale is 3144.7 km/arcsec.
Diameter estimates:
55.0 km assuming a 5% albedo, maximum of 3.1 sec for a central chord
22.4 km assuming a 30% albedo, maximum of 1.3 sec for a central chord
Cross-track diameter of 50.0 km used for deployment plan.
Star training set for 11509_Thersilochos, (2026/12/10 14:54UT) Object RA Dec mag sep mel Betelgeuse 05:56:37.9 +07:24:35 0.4 2.43 159 Bellatrix 05:26:34.7 +06:22:19 1.6 8.56 155 PPM 149639 05:56:21.9 +05:51:49 6.4 1.26 158 PPM 149705 05:59:44.2 +05:30:09 8.5 0.38 158 PPM 149744 06:01:38.8 +05:09:30 9.7 0.25 157 11509_Thersilo 06:00:40.0 +05:11:43 15.2 157 Positions are for equinox of date
Star training set for 11509_Thersilochos, (2026/12/10 14:54UT) Object RA Dec mag sep mel Betelgeuse 05:55:10.3 +07:24:26 0.4 2.43 159 Bellatrix 05:25:07.8 +06:20:58 1.6 8.56 155 PPM 149639 05:54:55.4 +05:51:39 6.4 1.26 158 PPM 149705 05:58:17.9 +05:30:07 8.5 0.38 158 PPM 149744 06:00:12.7 +05:09:32 9.7 0.25 157 11509_Thersilo 05:59:13.9 +05:11:43 15.2 157 Positions are for J2000