|
The existence of a belt of material in orbits with semi-major axis between 30-50 AU was suggested independently by G. Kuiper and K. Edgeworth in the late 1940's-early 1950's. With the detection, since 1992, of about 800 small bodies in the outer Solar System the existence of this Kuiper-Edgeworth belt seems well established. These small bodies are also referred to as "trans-Neptunian objects".
Simulations indicate that Gaia will observe a small number of trans-Neptunian objects. Despite this it will make a valuable contribution to the study of the outer Solar System by surveying the entire sky - thus covering areas inaccessible to ground-based instruments. Gaia will also provide the only direct measurement of the size of some objects, thus providing a measure of their albedo. A small number of trans-Neptunian objects detected by Gaia are expected to be binaries. With the astrometric accuracy of Gaia this binarity can be detected, leading to a direct measurement of the mass of these objects.
One of the most recently discovered (17 February 2004) trans-Neptunian objects is 2004 DW. From initial observations it appears that 2004 DW may be one of the largest of the trans-Neptunian objects detected to date, with a diameter of about 1500 km. The orbit - determined from recent observations and serendipitous discovery on old photgraphic plates - is very similar to that of Pluto's, as evident from the image above (see also the FAQ's about 2004 DW). The figure depicts the known planets in black and 2004 DW in red. From currently available data it appears that 2004 DW could be observed by Gaia.
For more about Gaia observations of Kuiper-Belt objects see the Information sheet on Trans-Neptunian Objects and Centaurs.
More about 2004 DW from the discovery team.
Image courtesy of Chad Trujillo.
[Published: 22/03/2004]
|
