Sydney, Feb 21 (IANS): Kepler-37b, the tiniest planet ever spotted, demonstrates that sun-like stars in our galaxy are capable of hosting much smaller planets than anything detected so far, say researchers.

Tim Bedding, professor and head of the University of Sydney School of Physics and Dennis Stello, Australian Research Fellow at the school, contributed to the discovery effort of an international team.

"That we have found one of these small and hard-to-detect planets suggests that they are abundant around other stars and lends weight to the belief that as planet size decreases their occurrence increases exponentially," said Stello, the journal Nature reports.

Kepler-37b is an exoplanet, or planet located outside the solar system, and is estimated to be a similar size to Earth's moon, which is only 3,475 kilometres in diameter, according to a Sydney statement.

Owing to this extremely small size and its highly irradiated surface, Kepler-37b is believed to be a rocky planet with no atmosphere or water, similar to Mercury.

The Kepler spacecraft made the Kepler-37b finding possible. The spacecraft was launched in 2009 with the goal of determining how often rocky planets occur in the habitable zone around sun-like host stars in our galaxy.

Over the course of 978 days of observations by the Kepler spacecraft, transit signals of three planets of the star Kepler-37, a slightly cooler and older star than our sun, were identified.

"Since the discovery of the first exoplanet we have known that other planetary systems can look quite unlike our own, but it is only now, thanks to the precision of the Kepler space telescope that we have been able to find planets smaller than the ones we see in our own solar system," said Bedding.