Fuel Efficient Galaxies: Sustaining Star Formation with Stellar Mass Loss

TL;DR

This paper investigates how stellar mass loss in disk galaxies can supply enough gas to sustain ongoing star formation, potentially reducing the need for external gas infall.

Contribution

It introduces a model quantifying stellar mass loss as a primary fuel source for star formation, aligning observed star formation rates with low external gas infall.

Findings

Stellar mass loss can supply most or all of the gas needed for star formation.

Recycled gas from stars can resolve the discrepancy between star formation and gas infall rates.

Stellar mass loss significantly contributes to the gas reservoir in late-type galaxies.

Abstract

We examine the importance of secular stellar mass loss for fueling ongoing star formation in disk galaxies during the late stages of their evolution. For a galaxy of a given stellar mass, we calculate the total mass loss rate of its entire stellar population using star formation histories derived from the observed evolution of the M*-star formation rate relation, along with the predictions of standard stellar evolution models for stellar mass loss for a variety of initial stellar mass functions. Our model shows that recycled gas from stellar mass loss can provide most or all of the fuel required to sustain the current level of star formation in late type galaxies. Stellar mass loss can therefore remove the tension between the low gas infall rates that are derived from observations and the relatively rapid star formation occurring in disk galaxies. For galaxies where cold gas infall rates have been estimated, we demonstrate explicitly that stellar mass loss can account for most of the deficit between their star formation and infall rates.