An international group of scientists solved the cause of the mysterious lack of a set of planets similar to the Earth. It turned out that the rocky exoplanets of the earthly type is actually much more than previously thought, and they hide in the bright light of double star systems, which is why they are difficult to detect. This is reported in the article published in the preprints of the ARXIV.
Observations were carried out with the help of two telescopes of the Jemin Observatory, located in Hawaii and Chile. Researchers studied 517 stars who had previously discovered candidates for exoplanets located within 500 parsec (1630 light years). These stars were mainly related to spectral classes F (yellow-white), G (yellow) and k (orange). The speckle-interferometers installed on the telescopes give a spatial resolution from less than ten to 500 astronomical units and allow to distinguish enough weak companions (on 5-9 stellar magnitudes weaker than the main star) in double star systems.
It turned out that 73 stars have star companions, while the average distance between both stars reaches a hundred astronomical units (one astronomical unit is approximately equal to the distance from the Sun to the Earth). The distance between stars in systems in which there are exoplanets, a little more than in commonly observed double systems, that is, scientists revealed a real deficit with exoplanets of systems with close starboard companions. The deficiency is explained by the fact that exoplans with the size of the Earth is difficult to find a transit method when both stellar companion rotate quite closely from each other.
Approximately 50 percent of stars in the galaxy are represented by double systems, so the results of the study indicate that scientists could miss a plurality of the globe planets when searching for exoplanets by the transit method, when the object passes on the background of the star disk, reducing its visible brightness. In close double systems, the drop in brightness can be masked by the presence of a star-companion.