2003UB 313 —the 10 th planet or only the biggest known KBO?

Main page▹Observations	15.1.2007 \|

2003UB₃₁₃—the 10^th planet or only the biggest known KBO?

At 97 AU from the Sun and about 3000 km diameter, the Kuiper-belt object 2003UB₃₁₃ gleamed only at 18.9^m on January, 2006. Although slightly bigger than Pluto, this object appears about 100× dimmer. Still amateur astronomers can capture it with backyard telescope and CCD camera.

No matter if the 2003UB₃₁₃ KBO should be called the 10^th planet, because it is bigger than Pluto, or Pluto should be no longer called a planet, because the 2003UB₃₁₃ KBO is bigger than it, imaging the object of 18.9^m, relatively close to horizon, can be a challenging task for amateur astronomer. Imaging the Pluto with its 14^m brightness is an easy task these days—modern CCD camera can record its light within seconds even on small 6 inch telescope. But capturing of almost 19^m object with backyard telescope would be considered impossible only ten years ago.

Kamil Hornoch used his 35 cm (approx. 13.8 inch), f/4.7 Newtonian reflector and G2CCD-0400 camera to image the 10^th planet during three nights on January, 2006.

January 27th, 2006, exposure 15.5 min, binning 2 × 2, no filter

January 27^th, 2006, exposure 15.5 min, binning 2 × 2, no filter

January 28th, 2006, exposure 17 min, binning 2 × 2, no filter

January 28^th, 2006, exposure 17 min, binning 2 × 2, no filter

January 29th, 2006, exposure 16.5 min, binning 2 × 2, no filter

January 29^th, 2006, exposure 16.5 min, binning 2 × 2, no filter

Notice the 2003UB₃₁₃ disappeared on the image from January 28^th, 2006—the KBO virtually merged with the background star.

The same DSS-2 (Digitized Sky Survey - 2) field is displayed below for reference.

The DSS-2 red-light image of the same field

Both successful 2003UB₃₁₃ observations were sent to MPC. Positional measurement error was only a few tenths of arc second, which quite satisfactory for a backyard telescope.

   Date (UT)           R.A.         Decl.      Residuals ["]
2006 01 27.77979   01 35 16.75   -05 32 33.3    0.1-  0.3+
2006 01 29.77124   01 35 17.94   -05 32 04.1    0.3+  0.4-

Epoch 2006 Mar. 6.0 TT = JDT 2453800.5                  MPC
M 197.63680              (2000.0)            P               Q
n   0.00177056     Peri.  151.42911     -0.91261338     -0.01855121             T = 2545502.32333 JDT
a  67.6700187      Node    35.86957     -0.34975394     -0.48181998             q =    37.7767188
e   0.4417510      Incl.   44.18694     +0.21168139     -0.87607383
P 557              H   -1.2           G   0.15           U   3
From 186 observations at 14 oppositions, 1954-2006, mean residual 0".44.

Images from G2CCD-0400 captured and processed by Kamil Hornoch.

The Digitized Sky Survey was produced at the Space Telescope Science Institute under U.S. Government grant NAG W-2166. The images of these surveys are based on photographic data obtained using the Oschin Schmidt Telescope on Palomar Mountain and the UK Schmidt Telescope. Acknowledgments.