Pluto's place in the solar system has taken another hammering by being lumped in with even more dwarf planets.
Pluto was controversially demoted from the solar system A-list in 2006 after it was found to lack the fundamental scientific standards required to be a planet.
It joined the lower ranks as a dwarf planet, alongside four others.
News that makes sense
Your trusted source for staying up-to-date with the world around you. Get free daily news updates and analysis, straight to your inbox.
But scientists at Canberra's Australian National University say they've redefined classification rules, which means the number of dwarf planets must rise to around 50.
It potentially gives scientists continually clamouring for Pluto's promotion new reason to give up hope.
Based on current estimates, dwarf planets are considered icy objects with radii larger than 400km.
Differences of distinction
But Charley Lineweaver and Marc Norman from the ANU's Planetary Science Institute believe it should be closer to 200km.
They believe a key problem is the distinction between dwarf planets and the thousands of small solar system bodies that exist is whether the object is round or not.
Dr Lineweaver said the smaller bodies, usually irregularly shaped, like potatoes, were at a distinct disadvantage.
He and Dr Norman worked out that a 200km "potato radius" for icy objects and a 300km radius for strong, rocky objects was akin to the dwarf planet classification.
"Our proposed 200km potato radius for icy moons would substantially increase the number of trans-Neptunian objects classified as dwarf planets," their paper reads.
The Potato Radius: a Lower Minimum Size for Dwarf Planets, is due to be published in the proceedings of the ninth Australian Space Science Conference.
