The original orbit for this object was based on only three oppositions, so there was some uncertainty in the predicted position for old DSS images. Fortunately, two mutually-consistent images from 1989 were found 32" from the expected location.
Of some concern was the fact that the two images were not along the line-of-variation. In fact, the astrometry from the discovery night on December 12, 2004 is poor and created a significant error in the prediction in 1989 because of the small amount of current astrometry.
The following astrometry was submitted to the Minor Planet Center:
K04XJ2A 1989 08 29.40000 01 52 19.25 +52 15 40.8 261 K04XJ2A 1989 10 04.32639 01 48 37.60 +52 29 51.3 261At the end of this page are the elements and residuals before and with the new data. The new orbit is much more accurate because the object has now been observed for 19 years instead of four years. 2004 XA192 was numbered on 2010-01-30.
View the Discovery Announcement. See also MPEC 2008-Y74.
1989 Oct. 04.32639 UTC RA 01h48m37.60s Dec. +52°29'51.3" 80-minute exposure Size = 150" x 150" Palomar Mountain-DSS plate XP197-A0VX | |
1989 Aug. 29.40000 UTC RA 01h52m19.25s Dec. +52°15'40.8" 60-minute exposure Size = 150" x 150" Palomar Mountain-DSS plate XJ197-A0AG | |
2004 XA192
Epoch 2009 June 18.0 TT = JDT 2455000.5 MPC M 349.26051 (2000.0) P Q n 0.00306197 Peri. 132.30940 -0.27085068 -0.90708252 T = 2458507.87328 JDT a 46.9679552 Node 328.55321 +0.59572452 +0.10500585 q = 35.4658599 e 0.2448924 Incl. 38.14641 +0.75614298 -0.40764576 P 322 H 4.0 G 0.15 U 4 From 11 observations at 3 oppositions, 2004-2009, mean residual 0".32. Residuals 20041212 644 0.1- 0.5+ 20050313 644 (0.7- 3.0-) 20081221 695 0.0 0.2- 20041212 644 0.1+ 0.4+ 20051105 644 0.2- 0.7- 20081222 695 0.0 0.1- 20041212 644 0.1+ 0.4+ 20051105 644 0.2- 0.7- 20081231 H06 0.1- 0.4+ 20050311 644 0.1+ 0.3- 20081221 695 0.0 0.2- 20090101 H06 0.2+ 0.4+
2004 XA192
Epoch 2009 June 18.0 TT = JDT 2455000.5 MPC M 349.35133 (2000.0) P Q n 0.00306098 Peri. 132.15354 -0.26842963 -0.90781484 T = 2458479.34647 JDT a 46.9781680 Node 328.55662 +0.59542935 +0.10656985 q = 35.4753729 e 0.2448541 Incl. 38.14570 +0.75723802 -0.40560459 P 322 H 4.0 G 0.15 U 3 From 13 observations at 4 oppositions, 1989-2009, mean residual 0".41. Residuals 19890829 675 0.1+ 0.1+ 20050311 644 0.1- 0.0 20081221 695 0.1- 0.5- 19891004 675 0.2+ 0.5- 20050313 644 (0.8- 2.7-) 20081222 695 0.1- 0.5- 20041212 644 0.0 1.0+ 20051105 644 0.2- 0.4- 20081231 H06 0.2- 0.0 20041212 644 0.2+ 0.9+ 20051105 644 0.2- 0.3- 20090101 H06 0.1+ 0.0 20041212 644 0.2+ 0.9+ 20081221 695 0.1- 0.6-
DSS precovery images are from DSS plate archive scans, which are © copyright California Institute of Technology.