RECON: TNO occultation with 469421

Event between (469421) 01XD255 and star GA1140:03180000 with event index number of 2252185

Geocentric closest approach at 2025/04/17 12:07:36 UTC

J2000 position of star is 09:30:32.0 +25:06:47
Equinox of date position of star is 09:31:55.5 +25:00:21
Stellar brightness G=15.9, use SENSEUP=128 with the MallinCam and and exposure time of 2 seconds with the QHY174 camera.
Star is 120 degrees from the moon. Moon is 83% illuminated.
Apparent brightness V=21.7

Object is 38.0 AU from the Sun and 37.7 AU from the Earth.
Apparent velocity is 6.6 km/sec on the sky relative to the star, or, 0.9 arcsec/hr.
The 1-sigma error in the time of the event is 264 seconds.
The 1-sigma cross-track error in the shadow position is 1370 km.

The object has an absolute magnitude Hv=5.8
Diameter=420.7 km assuming a 5% albedo -- 64.0 sec chord
Diameter=171.8 km assuming a 30% albedo -- 26.1 sec chord
Dynamical classification is 3:2E
 
 
 
 
 
 
 
 

Star training set for 469421, (2025/04/17 12:07UT)
Object            RA         Dec     mag  sep  mel
Regulus        10:09:43.0 +11:50:33  1.3 15.90 107
1Kap Leo       09:26:07.3 +26:04:19  4.5  1.70 122
PPM 099579     09:27:38.3 +25:27:54  8.5  1.09 121
PPM 099653     09:33:18.8 +24:51:02  9.2  0.34 120
PPM 099623     09:31:49.0 +24:59:59 10.4  0.04 120
469421         09:31:59.3 +25:00:03 15.9       120
Positions are for equinox of date

Azimuth is measured in degrees eastward from north. North is at an azimuth of 0, due East is at an azimuth of 90 degrees, due South is 180, and due West is 270.

Do not use the listing below for the RECON CPC 1100 telescopes. This is provided for other non-team facilities.

Star training set for 469421, (2025/04/17 12:07UT)
Object            RA         Dec     mag  sep  mel
Regulus        10:08:21.9 +11:58:02  1.3 15.90 107
1Kap Leo       09:24:39.2 +26:10:55  4.5  1.70 122
PPM 099579     09:26:10.6 +25:34:32  8.5  1.09 121
PPM 099653     09:31:51.6 +24:57:48  9.2  0.34 120
PPM 099623     09:30:21.6 +25:06:42 10.4  0.04 120
469421         09:30:32.0 +25:06:47 15.9       120
Positions are for J2000

Event circumstances last updated at 2024/03/04 05:31:53 UT

Marc W. Buie, Southwest Research Institute

RECON