NEW TRANSNEPTUNIAN OBJECT 1994 TG2
            
This photo shows the faint image (arrow) of a new transneptunian
object, discovered with the ESO 3.5-metre New Technology Telescope in
October 1994. It is here seen in a negative reproduction (dark stars
on white sky) of the CCD frame on which it was first noticed.

It was detected because of its extremely slow motion, only 3
arcsec/hour.  Six accurate positions were measured and allowed to
determine an approximate distance of about 42 AU, that is 6300 million
kilometres from the Sun. This is far outside the orbit of the
outermost, large planet, Neptune (4500 million kilometres); hence the
classification as a "transneptunian" object.

It has in the meantime been given the designation "1994 TG2" by the
Minor Planet Center of the International Astronomical Union. The
observed magnitude is about 24, i.e., it is about 16 million times
fainter than the faintest objects that can be perceived with the
unaided eye. Its diameter is probably 100 - 200 kilometres.

1994 TG2 is the 17th transneptunian object found during the past two
years. Nine of these have distances between 31 and 36 AU, the other
eight between 40 and 45 AU. None have so far been found in the gap in
between; this may be an effect of Neptune's gravitational attraction.
Colour measurements of some of the brightest have shown that they are
unusually red.

The transneptunian objects represent an entirely new class of objects
in the solar system. It is not yet clear how they may be related to
other minor bodies like comets and minor planets, and whether Pluto
and its moon Charon, as well as the Neptunian moon Triton (which was
observed from close quarters by Voyager 2 in 1989), also belong to
this class.

Technical information: Unfiltered 16 minutes gunn-r exposure with
EMMI. North is up and East is to the left.  1 pixel = 0.265 arcsec;
the field measures 51 x 38 arcsec. Observer: O. Hainaut (who also
discovered 1994 TG2).

This is ESO Press Photo 02/94. It may be reproduced, if credit is
given to the European Southern Observatory.  Copyright: ESO
Information and Photographic Service, Karl-Schwarzschild-Strasse 2,
D-85748 Garching, Germany.