RECON: TNO occultation with 98WS31

Event between 98WS31 and star GA1200:02130483 with event index number of 1238732

Geocentric closest approach at 2023/02/03 11:50:07 UTC

J2000 position of star is 05:57:32.0 +30:05:02
Equinox of date position of star is 05:59:00.7 +30:05:06
Stellar brightness G=16.0, use SENSEUP=128 with the MallinCam and and exposure time of 2 seconds with the QHY174 camera.
Star is 20 degrees from the moon. Moon is 95% illuminated.
Apparent brightness V=23.6

Object is 33.2 AU from the Sun and 32.5 AU from the Earth.
Apparent velocity is 16.3 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 424 seconds.
The 1-sigma cross-track error in the shadow position is 1269 km.

The object has an absolute magnitude Hv=8.3
Diameter=134.3 km assuming a 5% albedo -- 8.2 sec chord
Diameter=54.8 km assuming a 30% albedo -- 3.4 sec chord
Dynamical classification is 3:2E
 
 
 
 
 
 
 
 

Star training set for 98WS31, (2023/02/03 12:10UT)
Object            RA         Dec     mag  sep  mel
Betelgeuse     05:56:25.4 +07:24:34  0.4 22.68  29
Alnath         05:27:45.2 +28:37:29  1.6  6.97  27
PPM 095117     05:58:01.8 +28:56:38  6.5  1.16  20
PPM 095186     06:00:24.7 +29:59:02  7.5  0.32  20
PPM 071063     06:00:04.3 +30:12:28  8.9  0.26  20
98WS31         05:59:00.9 +30:05:06 16.0        20
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 98WS31, (2023/02/03 12:10UT)
Object            RA         Dec     mag  sep  mel
Betelgeuse     05:55:10.3 +07:24:26  0.4 22.68  29
Alnath         05:26:17.5 +28:36:23  1.6  6.97  27
PPM 095117     05:56:33.8 +28:56:32  6.5  1.16  20
PPM 095186     05:58:55.9 +29:59:01  7.5  0.32  20
PPM 071063     05:58:35.4 +30:12:27  8.9  0.26  20
98WS31         05:57:32.0 +30:05:02 16.0        20
Positions are for J2000

Event circumstances last updated at 2023/01/10 03:22:50 UT

Marc W. Buie, Southwest Research Institute

RECON