What does the “typical” exosolar system look like? We know that it will not probably look like our own solar system, since our well-known planets do not contain whole classes of planets (hot Jupiters! Mini-Neptunes!) That we have found elsewhere. And our discovery methods are heavily biased in the direction of planets that bore close to their hostess, so we don't really have a strong idea of what could be lurking in more distant jobs.
A new study that was released on Thursday describes a search for what is called “micro -run” events, whereby a planet acts as a gravity lens that increases the star in a job, so that it is briefly colored. These events are difficult to catch, but may indicate the presence of planets in more distance jobs. The researchers behind the new work find instructions that there is an important population of rocky super-earths traveling in jobs comparable to those of Jupiter and Saturn.
Lenses go micro
The two primary methods that we have used to discover exoplanets are called transit and radial speed. In the transit method we simply look at the star for dips in the light that it sends to the earth, which can be an indication of a planet that runs in a way that overshadows a small fraction of the star. For radial speed we look for red or blue -shifts in the light received from the star, caused by a planet that draws the star in different directions while it turns.
It is clear that the gravity influence of a planet is stronger when it is closer to the hostess. And stars can dimming temporarily for all sorts of reasons, so we have generally set a standard for discovery in which multiple transits are observed. That in turn means a shorter orbital period, and so we also influence ourselves in the direction of discovering planets that are close to their host. As a result, the majority of what we know about exosolar systems come from planets that are much closer to their hosts than the earth at the sun. Even the most distant object discovered by the Kepler Mission -jobs is only about as far away as Mars.
