RECON: TNO occultation with 98WY31

Event between 98WY31 and star UC4-573-029102 with event index number of 106548

Geocentric closest approach at 2018/02/22 11:46:08 UTC

J2000 position of star is 06:26:07.2 +24:24:27
Equinox of date position of star is 06:27:06.9 +24:23:49
Stellar brightness R=15.3
Star is 44 degrees from the moon. Moon is 41% illuminated.
TNO apparent brightness V=23.3

TNO is 43.2 AU from the Sun and 42.6 AU from the Earth.
The TNO is moving 11.9 km/sec on the sky relative to the star, or, 1.4 arcsec/hr.
The 1-sigma error in the time of the event is 917 seconds.
The 1-sigma cross-track error in the shadow position is 3049 km.

The TNO has an absolute magnitude Hv=6.8
Diameter=257.0 km assuming a 5% albedo -- 21.7 sec chord
Diameter=104.9 km assuming a 30% albedo -- 8.8 sec chord
Dynamical classification is CLASSICAL
 
 
 
 
 
 
 
 

Star training set for 98WY31, (2018/02/22 11:46UT)
Object            RA         Dec     mag  sep  mel
Pollux         07:46:25.5 +27:58:51  1.1 18.10  61
Alhena         06:38:45.6 +16:22:56  1.9  8.46  46
PPM 095919     06:25:50.8 +25:02:15  6.3  0.71  43
PPM 095926     06:26:07.6 +24:17:27  8.5  0.27  43
PPM 095979     06:28:01.0 +24:12:49  9.9  0.26  44
PPM 095953     06:27:02.7 +24:22:32 10.7  0.05  43
98WY31         06:27:14.0 +24:23:44 15.3        44
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.

Event circumstances last updated at 2016/03/22 17:05:22 UT

Marc W. Buie, Southwest Research Institute

RECON