Australasian Science: Australia's authority on science since 1938

New “Puffy Planet” Found

By David Reneke

A “puffy planet” has been discovered, as well as fresh evidence that asteroids have delivered water to exoplanets.

The full text of this article can be purchased from Informit.

The Australian discovery of a strange exoplanet orbiting a small cool star 500 light years away is challenging ideas about how planets form. “We have found a small star, with a giant planet the size of Jupiter, orbiting very closely,” said George Zhou of The Australian National University. “It must have formed further out and migrated in, but our theories can’t explain how this happened.”

In the past two decades more than 1800 extrasolar planets have been discovered outside our solar system orbiting around other stars. The host star of the latest exoplanet, HATS-6, is classed as an M-dwarf, which is one of the most numerous types of stars in the galaxy. But because they’re cool they are also dim, making M-dwarf stars difficult to study.

HATS-6 emits only 5% of the light of our sun. The giveaway that the faint star had a planet circling it was a dip in its brightness caused as the planet passed in front of the star, observed by small robotic telescopes including telescopes at the ANU’s Siding Spring Observatory.

One of the world’s largest telescopes, the Magellan Telescope in Chile, and an amateur astronomer, TG Tan, helped the team confirm that the signal was a planet and not a blip in the system. “TG Tan ... was able to catch the transit of the planet from Perth after it had set over our horizon,” Zhou said. Subsequent observations from the Chilean...

The full text of this article can be purchased from Informit.