RECON: TNO occultation with 98WS31

Event between 98WS31 and star UC4-598-020058 with event index number of 167063

Geocentric closest approach at 2018/12/08 23:04:10 UTC

J2000 position of star is 05:24:47.6 +29:34:03
Equinox of date position of star is 05:25:54.1 +29:34:56
Stellar brightness R=16.6, use SENSEUP=128
Star is 164 degrees from the moon. Moon is 3% illuminated.
TNO apparent brightness V=23.4

TNO is 32.6 AU from the Sun and 31.6 AU from the Earth.
The TNO is moving 24.5 km/sec on the sky relative to the star, or, 3.8 arcsec/hr.
The 1-sigma error in the time of the event is 333 seconds.
The 1-sigma cross-track error in the shadow position is 2140 km.

The TNO has an absolute magnitude Hv=8.3
Diameter=134.3 km assuming a 5% albedo -- 5.5 sec chord
Diameter=54.8 km assuming a 30% albedo -- 2.2 sec chord
Dynamical classification is 3:2E
 
 
 
 
 
 
 
 

Star training set for 98WS31, (2018/12/08 23:04UT)
Object            RA         Dec     mag  sep  mel
Aldebaran      04:37:00.6 +16:32:45  0.8 17.21 154
Alnath         05:27:29.4 +28:37:18  1.6  1.02 165
22 Aur         05:24:34.9 +28:57:10  6.4  0.70 164
PPM 094319     05:24:12.7 +29:44:43  7.9  0.42 164
PPM 094349     05:26:30.3 +29:37:49  9.0  0.12 164
98WS31         05:26:00.0 +29:35:01 16.6       165
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, (2018/12/08 23:04UT)
Object            RA         Dec     mag  sep  mel
Aldebaran      04:35:55.3 +16:30:30  0.8 17.21 154
Alnath         05:26:17.5 +28:36:24  1.6  1.02 165
22 Aur         05:23:22.9 +28:56:10  6.4  0.70 164
PPM 094319     05:23:00.2 +29:43:43  7.9  0.42 164
PPM 094349     05:25:17.9 +29:36:53  9.0  0.12 164
98WS31         05:24:47.6 +29:34:03 16.6       164
Positions are for J2000

Event circumstances last updated at 2017/05/19 18:07:58 UT

Marc W. Buie, Southwest Research Institute

RECON