Dynamical Mass Measurement of the Young Spectroscopic Binary V343 Normae AaAb Resolved With the Gemini Planet Imager

TL;DR

This study measures the masses of the binary stars in V343 Normae using new imaging data, confirming their consistency with theoretical models and estimating the age of the beta Pictoris moving group at about 26 million years.

Contribution

First dynamical mass measurements of V343 Normae's binary components using Gemini Planet Imager data, improving understanding of young stellar systems.

Findings

Measured masses: M_Aa = 1.10 +/- 0.10 M_sun, M_Ab = 0.290 +/- 0.018 M_sun.

Masses agree with theoretical isochrones for the group's age.

Estimated beta Pictoris moving group age as 26 +/- 3 Myr.

Abstract

We present new spatially resolved astrometry and photometry from the Gemini Planet Imager of the inner binary of the young multiple star system V343 Normae, which is a member of the beta Pictoris moving group. V343 Normae comprises a K0 and mid-M star in a ~4.5 year orbit (AaAb) and a wide 10" M5 companion (B). By combining these data with archival astrometry and radial velocities we fit the orbit and measure individual masses for both components of M_Aa = 1.10 +/- 0.10 M_sun and M_Ab = 0.290 +/- 0.018 M_sun. Comparing to theoretical isochrones, we find good agreement for the measured masses and JHK band magnitudes of the two components consistent with the age of the beta Pic moving group. We derive a model-dependent age for the beta Pic moving group of 26 +/- 3 Myr by combining our results for V343 Normae with literature measurements for GJ 3305, which is another group member with resolved binary components and dynamical masses.