Occultation event with (11887) Echemmon, event index number 5111
Regions able to see the event: SAmericaN
Geocentric closest approach at 2026/12/08 06:21:51 UTC
J2000 position of star is 05:31:37.9 +13:05:14
Equinox of date position of star is 05:33:09.0 +13:06:19
Star is 159 degrees from the moon. Moon is 1% illuminated.
Stellar brightness G=14.9, apparent brightess of occulting body is G=15.5
Use an exposure time of 0.40 seconds with the standard RECON-QHY system.
SNR of 6.2 per integration for unocculted signal
Expected flux drop is 65% with SNR of 4.0 for the occulted depth (per occulted point)
Apparent velocity is 18.7 km/sec on the sky relative to the star, or, 22.4 arcsec/hr.
Position angle of asteroid motion is 69.7 degrees
The recommended exposure time corresponds to 7.5 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 38.5 km.
The sky-plane scale is 3009.7 km/arcsec.
Diameter estimates:
40.7 km assuming a 5% albedo, maximum of 2.2 sec for a central chord
16.6 km assuming a 30% albedo, maximum of 0.9 sec for a central chord
Cross-track diameter of 31.2 km used for deployment plan.
Star training set for 11887_Echemmon, (2026/12/08 06:22UT) Object RA Dec mag sep mel Betelgeuse 05:56:37.9 +07:24:35 0.4 8.11 150 Bellatrix 05:26:34.6 +06:22:19 1.6 6.93 155 35 Ori 05:35:26.2 +14:19:19 5.6 1.34 159 PPM 121013 05:30:58.6 +13:26:49 8.1 0.63 159 PPM 121063 05:33:27.3 +13:04:36 9.3 0.08 159 11887_Echemmon 05:33:09.0 +13:06:19 15.5 158 Positions are for equinox of date
Star training set for 11887_Echemmon, (2026/12/08 06:22UT) Object RA Dec mag sep mel Betelgeuse 05:55:10.3 +07:24:26 0.4 8.11 150 Bellatrix 05:25:07.8 +06:20:58 1.6 6.93 155 35 Ori 05:33:54.3 +14:18:20 5.6 1.34 159 PPM 121013 05:29:27.2 +13:25:39 8.1 0.63 159 PPM 121063 05:31:56.2 +13:03:32 9.3 0.08 159 11887_Echemmon 05:31:37.9 +13:05:14 15.5 159 Positions are for J2000