3 super-Earths discovered around distant star: Earth 3, 4 and 5?

31 Jul 2015

An illustration of how HD219134b might look. Image via NASA-JPL

Just over a week after the discovery of an Earth-like planet dubbed ‘Earth 2.0’, astronomers have now discovered what appear to be three super-Earths surrounding a distant dwarf star.

Located 21 light years from Earth, the three super-Earth planets orbit the star dubbed HD219134 and offer some of the most exciting opportunities for astronomers to analyse a planet’s atmosphere against the backdrop of a star.

The team has published its findings in the journal Astronomy & Astrophysics, which show that one of the planets – HD219134b – is the most exciting for astronomers.

According to NASA, the planet has the shortest orbit of the star at just three days per orbit and has been seen transiting across the face of the star from our view here on Earth.

Based off readings from NASA’s Spitzer space telescope, this super-Earth is about 1.6-times larger than our own planet but has nearly five times the mass.

Super Earths location

Beside the constellation Cassiopeia, the circle indicates the location of HD219134. Image via NASA/JPL-Caltech/DSS

Meanwhile, the other two planets in the system are believed to be even larger, with the first being 2.7-times bigger than Earth with an orbit of 6.8 days, while the third enormous planet is 8.7-times bigger than Earth with a 47-day orbit.

By their nature, super-Earths are like a go-between for our own planet and those of our neighbouring planets in the solar system as they tend to be larger in mass than our own planet, but not as large as, say, Jupiter.

However, HD219134b’s proximity to the star means that the planet is not capable of supporting liquid water, but could be reminiscent of Earth’s beginnings as a rocky volcanic world covered in flowing molten lava.

“Most of the known planets are hundreds of light years away. This one is practically a next-door neighbour,” said astronomer and study co-author Lars A. Buchhave of the Harvard-Smithsonian Center for Astrophysics in Cambridge, Massachusetts.

Colm Gorey was a senior journalist with Silicon Republic