An international team of scientists has discovered a rocky planet like Earth type that could support life, since it is in the habitable zone around its star, the orbital band where the distance to the star is the ideal to allow temperature range not too cold or hot, right for the existence of liquid water on the surface of any planet with the appropriate characteristics to be there.
The star around which spins this planet called GJ 667C, and is a class M red dwarf, located 22 light-years from Earth. The star is part of a triple star system, and has a chemical composition that differs from that of our Sun in the abundance of elements heavier than helium, such as iron, carbon and silicon. GJ 667C is poorer than the Sun in such heavy elements.
The other two stars of this triple system are orange dwarf or K dwarf, with a concentration of heavy elements is only 25 percent of our sun. These heavy elements are common materials in the composition of rocky planets such as Earth, Mars and Venus, so it was thought unlikely that the stars around poor in heavy elements possible the formation of lower mass planets than the typical gas giant, composed largely of hydrogen and helium. The unexpected finding indicates that there may be planets capable of harboring life as we understand, in many more places in the cosmos than assumed so far.
The new planet has temperatures suitable for liquid water on its surface by orbiting its star at a distance much less than that separating Earth from the Sun. M-class star or red dwarfs are much less bright stars the Sun, so that the planets obtained from them a level of heat similar to that enjoyed by the Earth must be much closer. That makes the time it takes to make a full turn around the star (the “year” astronomical) is also lower. In the case of the new planet, called GJ 667Cc, takes only 28 days to complete one orbit around its star.
The research team, comprising experts from Chile, USA, Australia and the UK, used data from the European Southern Observatory and processed using a new method of analysis. Were also used new measurements made by the WM Keck Observatory and the Magellan telescope II. The technique to detect the presence of planets is based on measuring the tiny “wobble” that the star experiences moving through the action of gravitational force exerted on it by the planets in its environment.
So far, it was considered unlikely that red dwarf stars of class M, which is among the most common in our galaxy, adequately to around with planets like uncovered. Following this finding, to see how such solar systems has changed. As noted by the astronomer Steven Vogt of the University of California at Santa Cruz, the detection of this planet, so close to our solar system and after such a short time search in the area, implies that there must be thousands in our galaxy billion Earth-like rocky like Earth, potentially capable of supporting life.
The newly discovered planet is not the only orbiting GJ 667C. Long ago, they discovered another rocky planet (GJ 667Cb) with mass greater than that of the Earth in an orbit much closer to its star than the new planet. GJ 667Cb takes only 7.2 days to revolve around its star and its distance to it is too small to have the correct temperature for the existence of liquid water. In GJ 667Cb, temperatures are too high for possible life.
The privileged position of GJ 667Cc makes receiving the right amount of heat from its star. In fact, receives only 90 percent of the light that comes to Earth from the Sun, but because much of the radiation reaching GJ 667Cc corresponds to the infrared bands, a higher percentage of energy that reaches that world is absorbed by it. Taking this into account, the calculations indicate that the planet absorbs from its star a total amount of energy comparable to the earth absorbs the sun’s mass of the planet is at least 4.5 times that of Earth, but remaining within the mass range of rocky planets, as opposed to the masses rather greater than the gas giants, planets lacking surface itself.
GJ 667Cc is now the new best candidate to possess liquid water on its surface, and perhaps even support life as we understand it. Observations in the solar system suggest that there may be a gas giant planet and a rocky planet with greater mass than the Earth and an orbital period of 75 days. However, you need to do more checks before we can properly confirm the existence of these two worlds.
Technological advances in astronomical instrumentation will allow scientists to scrutinize many red dwarf stars of class M, so look for the presence of rocky planets around them and, if applicable, to detect “fingerprints” indicative spectroscopic the existence of life on any of them, as noted by Anglada Escude.
The research team have also worked, among others, Eugenio Rivera of the University of California at Santa Cruz, Paul Butler of the Carnegie Institution for Science in the U.S., James Jenkins of the University of Chile, Pamela Arriagada and Dante Minniti of the Pontifical Catholic University of Chile, as well as specialists from the Australian Astronomical Observatory, the University of Southern Queensland, New South Wales, both in Australia, Hawaii at Manoa, and Hertfordshire in the UK.
