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

TL;DR

This paper reports the discovery of two new multiple planet systems around stars HD47186 and HD181433, including super-Earth, Neptune, and Jupiter-mass planets, highlighting the prevalence of multi-planet systems with low-mass exoplanets.

Contribution

First detection of multiple planet systems around HD47186 and HD181433, expanding knowledge of low-mass exoplanets in multi-planet configurations.

Findings

Discovered a hot Neptune and a Saturn-mass planet in one system.

Identified a super-Earth and two Jupiter-mass planets in another system.

Confirmed that 80% of low-mass exoplanets are in multiple systems.

Abstract

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