Recently, NASA’ Kepler Telescope discovered the smallest three planets found so far in another solar system. Even more interesting is that all three planets — one of them is the size of Mars — are solid planets, like Earth.

All three planets rotate around a star called KOI-961 and have sizes between 50% and 75% of the size of the Earth. The parent-Star is a “red dwarf” star relatively cool and small, with a diameter equal with one-sixth of the Sun’s diameter. Such stars are dominant category in our galaxy.

This is the tiniest solar system found so far,

said principal investigator John Johnson

It’s actually more similar to Jupiter and its moons in scale than any other planetary system. The discovery is further proof of the diversity of planetary systems in our galaxy.

It’s almost like you took a shrink gun and zapped a planetary system, the whole thing, including the sun,

It is remarkable that all three planets are “rocky” planets, composed predominantly of solid matter, a feature that Kepler’s scientists have met rarely. There are more than 700 exoplanets discovered until now but only a few of them are solid.

All three planets orbit very close to their parent-star, needing less than two days to compplete the synodical period. The discovery was made ​​by astronomers from the California Institute of Technology, USA, and is the smallest solar system found so far.

The surface temperatures of these planets range from 720 Kelvin (836 degrees F) to 450 Kelvin (350 degrees),

Johnson said.

I can’t express how excited I am to find a Mars-sized planet,

Johnston said.

It’s already so hard finding something the size of the Earth.

The scientists detailed their findings today (Jan. 11) here at the annual meeting of the American Astronomical Society.

Science paper: Characterizing the Cool KOIs III. KOI-961: A Small Star with Large Proper Motion and Three Small Planets