NEW SOLAR SYSTEM FOUND TO HAVE 7 EARTH-SIZE PLANETS

Astronomers have discovered seven Earth-like exo- planets orbiting the same star, 40 light years away from Earth.

The findings were revealed through a study that was published on 22 February in a journal called Nature and through a news conference, held at the NASA headquarters in Washington.

KEY POINTS

• The seven planets have been found to be in a tight circle 
• around a star called TRAPPIST-1, which is almost one tenth the size of the sun and about a quarter as warm.
• The seven of them are distanced at a space five times smaller than the distance between Mercury and our sun.
• While the planet closest to the star takes about just one and half days to orbit around it, the farthest one is reported to take about 20 days.
• Despite such proximity to the sun-like star, these planets are not unbearably warm.
• Estimates of their mass indicate that they are all rocky planets.
• Three of the seven planets-TRAPPIST-1e, f and g fall in the habitable zone, leading to the possibility of them having water on their surface.
• While the first three planets according to the researchers would be too warm to support liquid water, the farthest one would be too cool.

According to researchers, TRAPPIST-1f looks to be the best candidate for supporting life. It is a bit cooler than Earth but it may have the right atmosphere and though TRAPPIST-1 is a dwarf star, it would appear three times as big as the sun when looked upon from TRAPPIST-1f.

About the discovery

• The discovery was made by a team led by Michaël Gillon of the Université de Liège.
• Generally, ultracool dwarf stars like TRAPPIST-1 are very common in the galaxy and so, are largely overlooked.
• Gillon however, decided to study the space around one of these dwarf stars.
• The researchers used a telescope called TRAPPIST (TRAnsiting Planets and PlanetesImals Small Telescope) to observe its space.
• He noticed dimness at certain intervals in the star’s light.

Further observation helped them see shadows, little eclipses that interrupted the steady pattern of the starlight periodically. The shadows indicated planets, and further observation confirmed it.

Earlier they saw just three planets and slowly later they discovered all seven and were able to determine their orbital periods, distances from their star, masses and their radius.