The ebb and flow can transform a so-called "make the most out of life zone" around a few massive stars do uninhabitable. This - the main result of the analysis, recently conducted and published a group of astronomers led by Rene Heller (Rene Heller) of the Astrophysical Institute Potsdam (AIP).
Extrasolar planets or exoplanets are known for their existence outside of our solar system since 1995. In the search for life in outer space, scientists have focused their attention on exoplanets, which are located in the habitable zone. This means that they orbitiruyut sun at a distance where the temperature on the surface of the planetary allow presence of liquid water. Water is considered an essential and important component for life. Until now it was assumed that the two main indicators to determine the temperature of the planet: the distance to the central star and the composition of the global atmosphere. By studying the tides caused by malomassovymi stars on the example of their potential partners whose conditions are similar to those of the earth, Hailler and his colleagues decided that tidal effects modify the traditional concept of the suitability of areas of life.
Heller came to this conclusion based on three different effects. First, the tides can help to ensure that the axis of rotation of the planet will be perpendicular to its orbit in just a few million years. For comparison, the Earth’s axis is rejected by 23.5 degrees - an effect that is the cause of the seasons. Without this effect on Earth-like planets with the habitable zone would be no seasonal changes. On these planets will be present huge temperature differences between their poles, which will be in a constant state of deep frozen, and their hot equator will evaporate any atmosphere. This temperature difference will cause strong winds and storms.
The second effect of the tides - heating exoplanets, like the tidal heating of Io, the closest satellite of Jupiter, which is characterized by violent volcanic activity.
Finally, tides can cause the rotating period of the planet ("day" of the planet) to synchronize with the orbital period ("year" of the planet). This situation is identical to the position of the moon relative to the Earth: Moon shows only one face of the earth, the other side is known as the "dark side of the moon." As a result, one half of the exoplanet receives extreme radiation from the star, while the other half is frozen in eternal darkness.
Fit for life malomassovyh zone around stars are therefore not very comfortable and can not even fit for habitation. From the point of view of an observer malomassovye stars have so far been the most promising candidates for extrasolar planets suitable for life. Now, since the information Heller, Earth-like exoplanets standards that are already considered fit for life, should be revised to take account of tidal effects.
Heller and his colleagues have applied their theory to GI581g: the main candidate of exoplanets, which was recently recognized as fit for habitation. They find that it is likely to GI581g no seasons, and that her day is synchronized with the year. There on the planetary surface, most likely, there is no water, making the planet uninhabitable.
Heller said: "I think that the chances for life on extrasolar planets in the traditional fit for life malomassovyh zone around stars are zero, since the tidal effects. If you want to find a second Earth, it seems, you need to first seek a second sun . "
Original: Sciencedaily Translation: M. Potter