RECON: TNO occultation with 181855

Event between (181855) 98WT31 and star TYC22893-01704-1 with event index number of 148639

Geocentric closest approach at 2018/08/26 14:43:06 UTC

J2000 position of star is 04:47:05.5 +38:38:30
Equinox of date position of star is 04:48:19.5 +38:40:23
Stellar brightness V=11.2, use SENSEUP=8
Star is 101 degrees from the moon. Moon is 100% illuminated.
TNO apparent brightness V=23.1

TNO is 37.6 AU from the Sun and 37.8 AU from the Earth.
The TNO is moving 14.7 km/sec on the sky relative to the star, or, 1.9 arcsec/hr.
The 1-sigma error in the time of the event is 223 seconds.
The 1-sigma cross-track error in the shadow position is 4168 km.

The TNO has an absolute magnitude Hv=7.2
Diameter=218.8 km assuming a 5% albedo -- 14.9 sec chord
Diameter=89.3 km assuming a 30% albedo -- 6.1 sec chord
Dynamical classification is SCATEXTD
 
 
 
 
 
 
 
 

Star training set for 181855, (2018/08/26 14:43UT)
Object            RA         Dec     mag  sep  mel
Aldebaran      04:36:59.6 +16:32:43  0.8 22.27  95
3Iot Aur       04:58:12.7 +33:11:38  2.7  5.83 102
PPM 069587     04:43:06.5 +38:18:51  6.2  1.09 100
PPM 069615     04:45:51.6 +38:17:18  7.1  0.62 100
PPM 069613     04:45:49.2 +38:46:59  8.7  0.51 100
181855         04:48:21.8 +38:40:26 11.2       101
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 181855, (2018/08/26 14:43UT)
Object            RA         Dec     mag  sep  mel
Aldebaran      04:35:55.3 +16:30:30  0.8 22.27  95
3Iot Aur       04:56:59.6 +33:09:58  2.7  5.83 102
PPM 069587     04:41:50.6 +38:16:47  6.2  1.09 100
PPM 069615     04:44:35.6 +38:15:18  7.1  0.62 100
PPM 069613     04:44:32.9 +38:44:59  8.7  0.51 100
181855         04:47:05.5 +38:38:30 11.2       101
Positions are for J2000

Event circumstances last updated at 2018/02/06 17:41:12 UT

Marc W. Buie, Southwest Research Institute

RECON