Occultation event with (4707) Khryses, event index number 1660
Regions able to see the event: Europe
Geocentric closest approach at 2025/12/09 21:32:58 UTC
J2000 position of star is 03:08:13.5 +26:20:39
Equinox of date position of star is 03:09:45.9 +26:26:32
Star is 92 degrees from the moon. Moon is 70% illuminated.
Stellar brightness G=14.8, apparent brightess of occulting body is G=15.2
Use an exposure time of 0.70 seconds with the standard RECON-QHY system.
SNR of 9.3 per integration for unocculted signal
Expected flux drop is 59% with SNR of 5.4 for the occulted depth (per occulted point)
Apparent velocity is 12.9 km/sec on the sky relative to the star, or, 16.9 arcsec/hr.
Position angle of asteroid motion is 63.8 degrees
The recommended exposure time corresponds to 9.0 km per image.
The 1-sigma error in the time of the event is 1.7 seconds.
The 1-sigma cross-track error in the shadow position is 26.0 km.
The sky-plane scale is 2742.1 km/arcsec.
Diameter estimates:
43.8 km assuming a 5% albedo, aximum of 3.4 sec for a central chord
17.9 km assuming a 30% albedo, maximum of 1.4 sec for a central chord
Cross-track diameter of 37.8 km used for deployment plan.
Star training set for 4707_Khryses, (2025/12/09 21:33UT) Object RA Dec mag sep mel Aldebaran 04:37:24.7 +16:33:33 0.8 22.61 75 44Zet Per 03:55:46.2 +31:57:31 2.8 11.44 81 52 Ari 03:06:58.3 +25:21:16 6.1 1.26 93 PPM 092264 03:11:59.9 +26:59:37 7.3 0.74 92 PPM 092231 03:09:59.3 +26:04:05 8.8 0.38 92 PPM 092248 03:11:17.2 +26:23:31 10.6 0.34 92 4707_Khryses 03:09:45.9 +26:26:32 15.2 92 Positions are for equinox of date
Star training set for 4707_Khryses, (2025/12/09 21:33UT) Object RA Dec mag sep mel Aldebaran 04:35:55.4 +16:30:29 0.8 22.61 75 44Zet Per 03:54:07.9 +31:53:01 2.8 11.44 81 52 Ari 03:05:26.7 +25:15:19 6.1 1.26 93 PPM 092264 03:10:27.1 +26:53:48 7.3 0.74 92 PPM 092231 03:08:27.1 +25:58:13 8.8 0.38 92 PPM 092248 03:09:44.7 +26:17:41 10.6 0.34 92 4707_Khryses 03:08:13.5 +26:20:39 15.2 92 Positions are for J2000