The HARPS search for southern extra-solar planets. XVII. Super-Earth and Neptune-mass planets in multiple planet systems HD47186 and HD181433

摘要

This paper reports on the detection of two new multiple planet systems aroundsolar-like stars HD47186 and HD181433. The first system includes a hot Neptuneof 22.78 M_Earth at 4.08-days period and a Saturn of 0.35 M_Jup at 3.7-yearsperiod. The second system includes a Super-Earth of 7.5 M_Earth at 9.4-daysperiod, a 0.64 M$_Jup at 2.6-years period as well as a third companion of 0.54M_Jup with a period of about 6 years. These detections increase to 20 thenumber of close-in low-mass exoplanets (below 0.1 M_Jup) and strengthen thefact that 80% of these planets are in a multiple planetary systems.