Volans-Carina: A New 90 Myr Old Stellar Association at 85 pc

TL;DR

The paper introduces the Volans-Carina stellar association, a group of stars approximately 90 million years old at 75-100 parsecs, characterized through Gaia data, with implications for stellar and planetary studies.

Contribution

It identifies and characterizes a new stellar association, providing its age, membership list, and integrating it into the BANYAN Σ classification tool, enhancing star group understanding.

Findings

Age of 89 Myr with uncertainty range

Members are ~3 times brighter than Pleiades stars

More compact than similar-aged groups like AB Doradus

Abstract

We present a characterization of the new Volans-Carina Association (VCA) of stars near the Galactic plane (b ~ -10 deg) at a distance of ~75-100 pc, previously identified as group 30 by Oh et al. (2017). We compile a list of 19 likely members from Gaia DR2 with spectral types B8-M2, and 46 additional candidate members from Gaia DR2, 2MASS and AllWISE with spectral types A0-M9 that require further follow-up for confirmation. We find an isochronal age of $89_{-7}^{+5}$ Myr based on MIST isochrones calibrated with Pleiades members. This new association of stars is slightly younger than the Pleiades, with less members but located at a closer distance, making its members ~3 times as bright than those of the Pleiades on average. It is located further than members of the AB Doradus moving group which have a similar age, but it is more compact on the sky which makes it less prone to contamination from random field interlopers. Its members will be useful benchmarks to understand the fundamental properties of stars, brown dwarfs and exoplanets at ~90 Myr. We also provide an updated version of the BANYAN $\Sigma$ Bayesian classification tool that includes the Volans-Carina association.