NZ stargazers key in discovery of unusual exoplanet

A newly discovered exoplanet exhibits curious behaviour, orbiting just one member of a pair of stars in a binary star system, researchers report, nearly ignoring the companion star.

The international team of academic and amateur astronomers who compiled the data to identify the planet included many New Zealanders; researchers from the University of Auckland, Massey University, AUT and the University of Canterbury worked with a number of individuals using smaller telescopes such as  Jennie McCormick, whose privately owned Pakuranga Farm Cove Observatory is part of the Center for Backyard Astrophysics network.

The new study, published in Science today,  provides the first evidence that terrestrial planets can form in orbits similar to Earth’s, even in a binary star system where the stars are not very far apart. Although this planet itself is too cold to be habitable, the same planet orbiting a sun-like star in such a binary system would be in the so-called “habitable zone” -the region where conditions might be right for life. The first planet in a binary system was discovered by the Kepler space telescope in 2011, but the planet orbited both stars.
This artist’s rendering shows a newly discovered planet (far right) orbiting one star (right) of a binary star system. Credit: Image by Cheongho Han, Chungbuk National University, Republic of Korea.

“This discovery is exciting because we weren’t certain that terrestrial planets could form around one star of a binary star system,” says University of Auckland Department of Physics senior lecturer Nicholas Rattenbury in a media release. “This tells us there are many more stars in our Galaxy that could potentially be the host star to habitable planets.”

Scientists used a technique called gravitational microlensing to detect the exoplanet and its orbit. Microlensing measures the bending of light that occurs as a star passes behind another object. Distortions in this light can indicate the presence of an planet. Previous microlensing research involving New Zealand astronomers has found that that, on average, every star in the Milky Way has at least one companion planet. Another study involving the Japan/NZ collaboration MOA (Microlensing Observations in Astrophysics) also identified many ‘free floating’ planets, which do not orbit a star.

Lead author Andrew Gould of The Ohio State University singled out the work of amateur astronomer and frequent collaborator Ian Porritt of Palmerston North, New Zealand, who watched for gaps in the clouds on the night of April 24 to get the first few critical measurements of the jump in the light signal.

You can read more about the new research in national coverage, including:

Newstalk ZB: Kiwis play part in discovery of new planet
Radio New Zealand: New Earth-sized planet found
3 News: Kiwis scientists help find frozen Earth-like planet
MSN NZ News: Kiwis help find new Earth-like planet
TVNZ News: Kiwi astronomers ‘surprised’ to discover Earth-like planet
New Zealand Herald: Kiwi astronomers help discover Earth-like planet