The HARPS survey for southern extra-solar planets II. A 14 Earth-masses exoplanet around mu Arae

TL;DR

This paper reports the discovery of a 14 Earth-mass exoplanet orbiting mu Arae, detected via radial velocity with the smallest Doppler amplitude observed, contributing to understanding low-mass planet populations.

Contribution

It presents the first detection of a super-Earth-sized planet with minimal Doppler signal, expanding knowledge of low-mass exoplanets around Sun-like stars.

Findings

Detected a 14 Earth-mass planet with 9.5-day orbit

Measured the smallest Doppler amplitude of 4.1 m/s

Discussed the planet's classification as ice giant or super-Earth

Abstract

In this letter we present the discovery of a very light planetary companion to the star mu Ara (HD160691). The planet orbits its host once every 9.5days, and induces a sinusoidal radial velocity signal with a semi-amplitude of 4.1 m/s, the smallest Doppler amplitude detected so far. These values imply a mass of m2 sini = 14 earth-masses. This detection represents the discovery of a planet with a mass slightly smaller than that of Uranus, the smallest ``ice giant" in our Solar System. Whether this planet can be considered an ice giant or a super-earth planet is discussed in the context of the core-accretion and migration models.