Hubble telescope identifies planet found by NZ astronomers

American astronomers have identified the host star to a huge planet discovered in 2003 by Mount John observatory in South Canterbury.

The newly discovered host star, called OGLE-2003L-BLG-235/MOA-2003-BLG-53L, was found by scientists using the orbiting American Hubble telescope.

The identification comes as a welcome confirmation to Massey University astrophysicist Ian Bond.

"We essentially had a planet we couldn't see, orbiting around a star we couldn't see, so we needed the Hubble Telescope to have any chance of isolating the host star of the planet."

The findings were a breakthrough in understanding how planets were formed, Dr Bond said.

Scientists from universities in New Zealand and Japan began the cutting-edge microlensing project at Mount John in 1995.

"Stars are typically too small to be noticed without precise measurements, but if one star passes precisely enough in front of another star, the gravity of the foreground star acts like a giant lens, magnifying the light from the background star," he said.

The planet, several thousand light years away from Earth, has about 2-1/2 times the mass of Jupiter and orbits a star about 65 per cent the mass of our own Sun.

Hubble team leader David Bennett said identification of the host star was critical for a complete understanding of planets discovered by microlensing.

The Hubble telescope, orbiting 612km above the Earth's surface, took high-resolution images of the distant star that confirmed the scientists' discovery.

- NZPA