Professor Kaspar von Braun and his colleagues at the University of California at Berkeley and the State University at San Francisco discovered another interesting exoplanet in the double star system 55 in the constellation Cancer. There is a great likelihood that there is some type of life on the planet. Now this discovery causes heated debates in the scientific world.
The double star 55 Cancri, also known under the symbol HD 75 732 and located at a distance of approximately 40 light years from Earth, has long attracted the attention of scientists. The system includes yellow dwarf 55 Cnc A, very reminiscent of our Sun in terms of the mass, luminosity and other parameters (its radius is approximately 0.9 of that of the Sun), and a less massive red dwarf star 55 Cns B, orbiting at a distance of approximately one thousand astronomical units.
The first four planets orbiting the star 55 Cns were discovered in the late1990's - early 2000's. However, they were hot gas giants. After the discovery in 2002 of the planets 55 Cnc C and 55 Cnc D it turned out that there was a wide "gap" between them. However, the results of modular simulation showed that this space can be occupied by stable planetary orbits. Only in 2007 one of the study participants, Professor Geoffrey Marcy, "stumbled" upon the fifth planet - 55 Cnc F, whose mass is equal to 0.155 of the mass of Jupiter (approximately 46 Earth masses) and is removed from its parent star by approximately the same distance as Earth from the Sun.
The new planet was "unofficially" name Tatooine - the name of the homeland of "Star Wars" characters Anakin (the future Darth Vader) and Luke Skywalker, a planet with two suns. After von Braun's team with the help of an optical interferometer CHARA was able to clarify the astrophysical parameters of the star 55 Cnc A and its planets orbit, it was revealed that the conditions created on 55 Cnc F may be favorable for life. This means that the planet rotates in an orbit where the water remains liquid while only partially evaporating and freezing.
According to the estimates of the researchers, the planet spends 74 percent of its annual cycle inside the "zone of life". The average temperature of its surface is ranging from minus 52 degrees to plus 28 degrees Celsius.
Despite the fact that the mass of 55 Cnc F is much greater than that of Earth, there is a probability that it still has a solid surface or may have satellites consisting of rocks where water can exist. In addition, for water retention such satellites must have considerable mass, so there chances that these bodies will be inhabited are quite significant.
Large-scale search for planets around stars like the Sun started in 1994. Since then over 250 extrasolar planets have been discovered, whose existence is confirmed by observations with a variety of techniques. However, so far there is no technology that can safely identify such planets and provide proof of existence of life there. So far it has been impossible to obtain sharp images of these bodies. Only sufficiently large celestial bodies, similar in mass to Jupiter and Saturn that are the largest objects in the planetary-type solar system, have been observed. The smallest of the exoplanet in terms of mass are five times greater than Earth.
There is also a great deal of "candidate planets" with the mass of five to ten times greater than Earth's, so they may have a hard surface. Yet, it is not always possible to say with certainty that we are dealing with Earth-like planets. Sometimes weak perturbations of the stars are interpreted as the effect of the planets, whereas in fact it is just a manifestation of the activity of the stellar atmosphere, if not the result of a mathematical error. So far 55 Cnc F, according to an employee of the Astronomical Institute of St. Petersburg State University Roman Baluev, is just one of those "candidates for extrasolar planets."
"This planet is not particularly remarkable except for its location in the so-called" zone of life," a ring around a star where water could exist in liquid form. If the existence of the fifth planet in 55 Cancer is confirmed, in orbits around it we may expect warm satellites - "oceanides "hiding unknown forms of life in their depths."
Meanwhile, scientists have not ruled out the existence of small rocky planets like Earth, Mars and Venus between the fourth and fifth planets of 55 Cnc system. However, the technology able to test this hypothesis will appear only a few decades later.