Through three studies published in Nature Astronomy, a team of astronomers announced the discovery of six exoplanets using a new method. These planets are so close to their stars that they are evaporating and this phenomenon in turn leads to the creation of a ring of debris and gas. Precisely the detection of this ring, which then interferes in a particular way with the light from the same star, has allowed researchers to identify the same planets and this method could also prove useful in the future to detect further exoplanets that are at a similar stage.
The idea came in 2009 when astronomer Carole Haswell, from the Open University, England, examined Wasp-12b, a gaseous exoplanet that orbited very close to the star so that a year lasted only 26 hours. This close proximity caused the outer layers of this planet’s atmosphere to get lost in space and form a gas trail that interfered with the star’s light itself.
It was then that the same group of astronomers jumped at the idea of finding debris and trails like these to discover the exoplanets. That’s why Haswell herself, together with her colleagues, set up a new project, called the Dispersed Matter Planet Project, and checked 2700 Sun-like stars and discovered the same effect in relation to the disturbance of the light they emitted.
They then used more powerful telescopes to understand in greater detail what was happening around the stars showing this phenomenon and discovered in particular four exoplanets orbiting the star DMPP-1 and two others, one orbiting the star DMPP-2 and another around the star DMPP-3.
All six planets orbit around their stars much closer than Mercury is to the Sun. And all six were discovered using the above technique (confirmation of their existence was then obtained by the radial velocity method that examines the gravitational oscillations of the star induced by the planets themselves).
On the other hand, if this particular technique had not been used, these planets would probably have been imperceptible (at least with the techniques we have now) precisely because they were too close to their star. Haswell herself is enthusiastic about this new technique for the discovery of extrasolar planets, “a success beyond my wildest dreams”, as she says in Scientific American.
By the way, Venus herself may have gone through a similar phase in her past. Several models of the evolution of this planet, in fact, suggest that it has lost much of its water and atmosphere in the distant past precisely because of its proximity to the Sun and this dispersion of material has perhaps produced a similar trail.