Pluto's lowered celestial status will probably stick at an upcoming meeting of astronomers in Rio de Janeiro, an American astronomer predicted Sunday.

Pluto was reduced from a full-fledged planet -- the ninth in the Earth's solar system -- to dwarf planet at a meeting of the International Astronomical Union three years ago in Prague, Czech Republic.

The Houston Chronicle reported Stephen Maran, co-author of the recent book "Pluto Confidential," says politics may keep the only planet discovered by an American astronomer, Clyde Tombaugh, from regaining its former celestial status.

Maran suggests the meeting in Prague, coming during the Iraq war, was tainted by a bit of anti-Americanism, and the union twisted the knife by deciding dwarf planets such as Pluto were not planets.

"No resolution was submitted in the past months, so it is unlikely that the Pluto issue, or any other solar system naming matters, will come before the General Assembly," said Robert Williams, an astronomer in Baltimore who is the group's president-elect.

In Prague, a majority of the 424 who attended voted to lower Pluto to the level of a dwarf planet. Pluto was stripped of its name and given the identifying number of 134340.