Counting mass with Gaia: Mass Density of stars and stellar remnants in the solar neighborhood

TL;DR

This paper estimates the local mass density of stars and stellar remnants in the solar neighborhood using Gaia data, providing a model-free measurement to inform dark matter estimates.

Contribution

It presents the first model-free local mass density estimate based on Gaia data, accounting for unresolved binaries and missing low-mass stars.

Findings

Mass density with Kroupa IMF: 0.040+0.012/-0.006 M_sun/pc^3

Mass density with Chabrier IMF: 0.037+0.012/-0.006 M_sun/pc^3

Provides a benchmark for Galactic mass modeling.

Abstract

In the light of new full-sky surveys, many attempts of creating a consistent Galactic model were made. The main interest is to estimate the still poorly understood dark matter content. However, the results vary depending on methodology, assumptions, and baryonic distribution used. To understand this discrepancy, we take the first step by estimating the model-free local mass density of stars and stellar remnants. We use a complete sample from the Gaia Catalogue of Nearby Stars within 100 pc from the Sun, together with the data on the sample of the White Dwarfs and the recent estimate of the Neutron Stars concentration in the solar neighborhood. After correction for unresolved binary stars and accounting for missing low-mass stars, we find the local mass density of stars and stellar remnants in the solar neighborhood is $\rho_{100} = 0.040^{+0.012} _{ -0.006}M_\odot pc^{-3}$ with Kroupa IMF, and $\rho_{100} = 0.037^{+0.012}_{ -0.006}M_\odot pc^{-3}$ with Chabrier IMF.