RECON: TNO occultation with 55638

Event between (55638) 02VE95 and star GA0960:02407409 with event index number of 2250047

Geocentric closest approach at 2025/04/22 07:11:03 UTC

J2000 position of star is 06:57:07.5 +06:33:04
Equinox of date position of star is 06:58:25.4 +06:31:03
Stellar brightness G=17.0, use SENSEUP=128 with the MallinCam and and exposure time of 2 seconds with the QHY174 camera.
Star is 142 degrees from the moon. Moon is 37% illuminated.
Apparent brightness V=20.8

Object is 31.5 AU from the Sun and 31.8 AU from the Earth.
Apparent velocity is 16.1 km/sec on the sky relative to the star, or, 2.5 arcsec/hr.
The 1-sigma error in the time of the event is 156 seconds.
The 1-sigma cross-track error in the shadow position is 1329 km.

The object has an absolute magnitude Hv=5.6
Diameter=524.8 km assuming a 5% albedo -- 28.6 sec chord
Diameter=214.3 km assuming a 30% albedo -- 11.7 sec chord
Dynamical classification is 3:2E
 
 
 
 
 
 
 
 

Star training set for 55638, (2025/04/22 07:11UT)
Object            RA         Dec     mag  sep  mel
Betelgeuse     05:56:32.6 +07:24:35  0.4 15.40 128
Alhena         06:39:10.4 +16:22:32  1.9 10.93 140
PPM 151677     07:00:42.1 +07:16:49  6.1  0.94 143
PPM 151571     06:57:46.9 +05:58:10  7.6  0.57 142
PPM 151598     06:58:20.8 +06:27:38  9.5  0.06 142
55638          06:58:29.1 +06:30:58 17.0       143
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 55638, (2025/04/22 07:11UT)
Object            RA         Dec     mag  sep  mel
Betelgeuse     05:55:10.3 +07:24:26  0.4 15.40 128
Alhena         06:37:42.8 +16:23:57  1.9 10.93 140
PPM 151677     06:59:20.1 +07:19:00  6.1  0.94 143
PPM 151571     06:56:25.7 +06:00:15  7.6  0.57 142
PPM 151598     06:56:59.3 +06:29:44  9.5  0.06 142
55638          06:57:07.5 +06:33:04 17.0       142
Positions are for J2000

Event circumstances last updated at 2024/03/05 04:24:22 UT

Marc W. Buie, Southwest Research Institute

RECON