Occultation event with (4035) Thestor, event index number 5176
Regions able to see the event: Australia
Geocentric closest approach at 2026/12/11 19:17:41 UTC
J2000 position of star is 13:00:06.1 -14:50:22
Equinox of date position of star is 13:01:31.5 -14:59:03
Star is 90 degrees from the moon. Moon is 7% illuminated.
Stellar brightness G=14.6, apparent brightess of occulting body is G=15.4
Use an exposure time of 0.55 seconds with the standard RECON-QHY system.
SNR of 9.6 per integration for unocculted signal
Expected flux drop is 68% with SNR of 6.6 for the occulted depth (per occulted point)
Apparent velocity is 27.3 km/sec on the sky relative to the star, or, 23.3 arcsec/hr.
Position angle of asteroid motion is 115.7 degrees
The recommended exposure time corresponds to 15.0 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 34.1 km.
The sky-plane scale is 4216.3 km/arcsec.
Diameter estimates:
74.5 km assuming a 5% albedo, maximum of 2.7 sec for a central chord
30.4 km assuming a 30% albedo, maximum of 1.1 sec for a central chord
Cross-track diameter of 68.7 km used for deployment plan.
Star training set for 4035_Thestor, (2026/12/11 19:18UT) Object RA Dec mag sep mel Spica 13:26:37.0 -11:18:04 1.0 7.13 86 PPM 226546 12:57:18.5 -15:28:21 6.2 1.13 91 PPM 226599 12:59:28.6 -15:07:51 7.1 0.52 90 PPM 226651 13:01:46.1 -15:12:15 9.5 0.23 90 4035_Thestor 13:01:31.5 -14:59:03 15.4 89 Positions are for equinox of date
Star training set for 4035_Thestor, (2026/12/11 19:18UT) Object RA Dec mag sep mel Spica 13:25:11.5 -11:09:41 1.0 7.13 86 PPM 226546 12:55:53.2 -15:19:37 6.2 1.13 91 PPM 226599 12:58:03.3 -14:59:09 7.1 0.52 90 PPM 226651 13:00:20.7 -15:03:34 9.5 0.23 90 4035_Thestor 13:00:06.1 -14:50:22 15.4 90 Positions are for J2000