RECON: TNO occultation with 455171

Event between (455171) 99OM4 and star GA0820:22399334 with event index number of 1124316

Geocentric closest approach at 2021/07/07 21:09:29 UTC

J2000 position of star is 23:02:28.6 -07:52:12
Equinox of date position of star is 23:03:34.3 -07:45:23
Stellar brightness G=16.6, use SENSEUP=128 with the MallinCam and and exposure time of 2 seconds with the QHY174 camera.
Star is 98 degrees from the moon. Moon is 4% illuminated.
TNO apparent brightness V=23.8

TNO is 45.9 AU from the Sun and 45.4 AU from the Earth.
The TNO is moving 11.2 km/sec on the sky relative to the star, or, 1.2 arcsec/hr.
The 1-sigma error in the time of the event is 940 seconds.
The 1-sigma cross-track error in the shadow position is 4937 km.

The TNO has an absolute magnitude Hv=7.1
Diameter=229.1 km assuming a 5% albedo -- 20.5 sec chord
Diameter=93.5 km assuming a 30% albedo -- 8.4 sec chord
Dynamical classification is CLASSICAL
 
 
 
 
 
 
 
 

Star training set for 455171, (2021/07/07 21:09UT)
Object            RA         Dec     mag  sep  mel
Fomalhaut      22:58:50.1 -29:30:28  1.2 21.78 107
81 Aqr         23:02:30.7 -06:56:43  6.1  0.85  98
PPM 207103     23:05:02.0 -07:56:33  8.3  0.40  98
PPM 207082     23:03:52.8 -07:42:28  9.7  0.08  98
455171         23:03:35.7 -07:45:14 16.6        98
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 455171, (2021/07/07 21:09UT)
Object            RA         Dec     mag  sep  mel
Fomalhaut      22:57:39.6 -29:37:24  1.2 21.78 107
81 Aqr         23:01:23.6 -07:03:40  6.1  0.85  98
PPM 207103     23:03:54.9 -08:03:31  8.3  0.40  98
PPM 207082     23:02:45.7 -07:49:26  9.7  0.08  98
455171         23:02:28.6 -07:52:12 16.6        98
Positions are for J2000

Event circumstances last updated at 2021/01/23 20:30:31 UT

Marc W. Buie, Southwest Research Institute

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