Occultation event with (4035) Thestor, event index number 964
Regions able to see the event: Australia
Geocentric closest approach at 2025/05/10 10:49:53 UTC
J2000 position of star is 08:41:04.1 +05:52:02
Equinox of date position of star is 08:42:24.7 +05:46:32
Star is 74 degrees from the moon. Moon is 95% illuminated.
Stellar brightness G=14.3, apparent brightess of occulting body is G=15.2
Use an exposure time of 0.40 seconds with the standard RECON-QHY system.
SNR of 9.8 per integration for unocculted signal
Expected flux drop is 70% with SNR of 6.9 for the occulted depth (per occulted point)
Apparent velocity is 18.0 km/sec on the sky relative to the star, or, 17.2 arcsec/hr.
Position angle of asteroid motion is 354.5 degrees
The recommended exposure time corresponds to 7.2 km per image.
The 1-sigma error in the time of the event is 2.2 seconds.
The 1-sigma cross-track error in the shadow position is 13.2 km.
The sky-plane scale is 3774.5 km/arcsec.
Diameter estimates:
73.8 km assuming a 5% albedo, aximum of 4.1 sec for a central chord
30.1 km assuming a 30% albedo, maximum of 1.7 sec for a central chord
Cross-track diameter of 73.8 km used for deployment plan.
Star training set for 4035_Thestor, (2025/05/10 10:50UT) Object RA Dec mag sep mel Regulus 10:09:43.2 +11:50:32 1.3 22.39 56 Alphard 09:28:50.0 -08:46:11 2.0 18.59 60 4Del Hya 08:38:59.8 +05:36:49 4.2 0.86 75 PPM 154823 08:41:34.2 +06:28:29 7.7 0.73 75 PPM 154869 08:43:35.4 +05:46:49 9.8 0.29 74 PPM 154859 08:42:56.1 +05:42:39 10.6 0.15 74 4035_Thestor 08:42:24.7 +05:46:32 15.2 74 Positions are for equinox of date
Star training set for 4035_Thestor, (2025/05/10 10:50UT) Object RA Dec mag sep mel Regulus 10:08:21.9 +11:58:02 1.3 22.39 56 Alphard 09:27:35.2 -08:39:30 2.0 18.59 60 4Del Hya 08:37:39.3 +05:42:13 4.2 0.86 75 PPM 154823 08:40:13.3 +06:33:58 7.7 0.73 75 PPM 154869 08:42:14.8 +05:52:20 9.8 0.29 74 PPM 154859 08:41:35.5 +05:48:09 10.6 0.15 74 4035_Thestor 08:41:04.1 +05:52:02 15.2 74 Positions are for J2000