As a follow-up on our exoplanet hunting article a few days back, I just wanted to make a quick note on a new low mass exoplanet discovery that has just been made. This one is around 5 times the mass of Earth, making it the lightest known exoplanet to date. As i also mentioned in the article, we expect to find Earth-sized planets in the near future, but at least the scientists at Spanish Research Council and the University College London get to keep the trophy for a little while.

What is interesting about this discovery is that the presence of the planet was inferred from its perturbation of the orbit of another already known transiting planet in the same system. This means that the transits of the other Neptune-sized planet was perturbed slightly in a way that was modeled and fitted to match the presence of another smaller planet close to the bigger one. Observations of the radial velocity confirmed these predictions perfectly, and another rocky exoplanet (we now know 4) can be added to the list. With the very close orbit it doesn’t look like this planet can harbor any life, however.

Link to the press release.