Occultation event with (31342) 98MU31, event index number 1359
Regions able to see the event: Australia,NMexico
Geocentric closest approach at 2025/10/11 12:05:09 UTC
J2000 position of star is 03:47:09.3 -05:12:34
Equinox of date position of star is 03:48:26.0 -05:07:52
Star is 39 degrees from the moon. Moon is 75% illuminated.
Stellar brightness G=15.4, apparent brightess of occulting body is G=15.7
Use an exposure time of 0.90 seconds with the standard RECON-QHY system.
SNR of 7.1 per integration for unocculted signal
Expected flux drop is 57% with SNR of 4.0 for the occulted depth (per occulted point)
Apparent velocity is 13.0 km/sec on the sky relative to the star, or, 14.2 arcsec/hr.
Position angle of asteroid motion is 61.1 degrees
The recommended exposure time corresponds to 11.7 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 18.1 km.
The sky-plane scale is 3292.5 km/arcsec.
Diameter estimates:
49.0 km assuming a 5% albedo, aximum of 3.8 sec for a central chord
20.0 km assuming a 30% albedo, maximum of 1.5 sec for a central chord
Cross-track diameter of 47.4 km used for deployment plan.
Star training set for 31342_98MU31, (2025/10/11 12:05UT) Object RA Dec mag sep mel Rigel 05:15:46.7 -08:10:26 0.1 21.90 36 Menkar 03:03:37.8 +04:11:22 2.5 14.56 39 30 Eri 03:53:58.2 -05:17:10 5.6 1.39 38 PPM 186209 03:49:55.0 -04:20:39 7.9 0.87 38 PPM 186171 03:47:50.6 -05:22:37 9.9 0.29 39 31342_98MU31 03:48:26.0 -05:07:52 15.7 39 Positions are for equinox of date
Star training set for 31342_98MU31, (2025/10/11 12:05UT) Object RA Dec mag sep mel Rigel 05:14:32.3 -08:12:06 0.1 21.90 36 Menkar 03:02:16.8 +04:05:21 2.5 14.56 39 30 Eri 03:52:41.7 -05:21:41 5.6 1.39 38 PPM 186209 03:48:38.0 -04:25:18 7.9 0.87 38 PPM 186171 03:46:34.1 -05:27:20 9.9 0.29 39 31342_98MU31 03:47:09.3 -05:12:34 15.7 39 Positions are for J2000