High Contrast Imaging: Exoplanet and Low Stellar Mass Populations

Based on a colour and proper motion analysis, no planetary detections are recorded. Exploiting this enhanced survey sensitivity with Bayesian analysis, the population of 0.5 − 13 MJ planets at separations of 100 − 1000 AU is constrained with an upper frequency limit of 9% (at 95% confidence).<br><br>I also report the results of a FEROS radial velocity survey of low-mass binaries, the majority of which are high probability young moving group (YMG) members.

YMGs are prime targets for exoplanet imaging due to their youth (∼ 10 − 100 Myr), as any potential orbiting planet will be equivalently young and therefore luminous. Lucky imaging multiplicity surveys have recently identified hundreds of new YMG low-mass binaries, where a subsample of M-dwarf multiples have estimated orbital periods less than 50 years. Radial velocity measurements for 29 such targets are presented here, complementing the astrometric data.

This will allow enhanced orbital determinations and precise dynamical masses to be derived in a shorter timeframe than possible with astrometric monitoring alone. Derived dynamical masses will enable binary systems to be isochronally dated to a good level of precision. This dating can then potentially be applied to the YMG of which they are members, for improved age constraints on the full population of stars.

Improved YMG age constraints are critical for estimating the mass or initial entropy of imaged planets using mass-luminosity evolutionary models.