Occultation event with (11509) Thersilochos, event index number 4906
Regions able to see the event: Australia
Geocentric closest approach at 2026/11/27 12:39:44 UTC
J2000 position of star is 06:05:41.5 +05:41:41
Equinox of date position of star is 06:07:07.8 +05:41:26
Star is 25 degrees from the moon. Moon is 88% illuminated.
Stellar brightness G=16.2, apparent brightess of occulting body is G=15.3
Use an exposure time of 0.75 seconds with the standard RECON-QHY system.
SNR of 3.1 per integration for unocculted signal
Expected flux drop is 31% with SNR of 0.9 for the occulted depth (per occulted point)
Apparent velocity is 16.0 km/sec on the sky relative to the star, or, 18.1 arcsec/hr.
Position angle of asteroid motion is 68.1 degrees
The recommended exposure time corresponds to 12.0 km per image.
The 1-sigma error in the time of the event is 0.4 seconds.
The 1-sigma cross-track error in the shadow position is 28.7 km.
The sky-plane scale is 3180.1 km/arcsec.
Diameter estimates:
55.0 km assuming a 5% albedo, maximum of 3.4 sec for a central chord
22.4 km assuming a 30% albedo, maximum of 1.4 sec for a central chord
Cross-track diameter of 50.0 km used for deployment plan.
Star training set for 11509_Thersilochos, (2026/11/27 12:40UT) Object RA Dec mag sep mel Betelgeuse 05:56:37.8 +07:24:35 0.4 3.12 26 Bellatrix 05:26:34.5 +06:22:18 1.6 10.11 32 63 Ori 06:06:24.3 +05:24:58 6.4 0.33 26 PPM 149886 06:07:18.9 +05:44:01 7.6 0.06 25 11509_Thersilo 06:07:07.8 +05:41:26 15.3 25 Positions are for equinox of date
Star training set for 11509_Thersilochos, (2026/11/27 12:40UT) Object RA Dec mag sep mel Betelgeuse 05:55:10.3 +07:24:26 0.4 3.12 26 Bellatrix 05:25:07.8 +06:20:58 1.6 10.11 32 63 Ori 06:04:58.1 +05:25:12 6.4 0.33 26 PPM 149886 06:05:52.6 +05:44:16 7.6 0.06 25 11509_Thersilo 06:05:41.5 +05:41:41 15.3 25 Positions are for J2000