Age distribution of the central stars of galactic disk planetary nebulae

TL;DR

This study develops multiple methods to estimate the ages of central stars of planetary nebulae in the galactic disk, revealing most are under 6 Gyr old with a peak around 2-4 Gyr, and compares these with white dwarf age distributions.

Contribution

The paper introduces new combined methods for estimating CSPN ages using nebular and stellar properties, improving age distribution analysis in the galactic disk.

Findings

Most CSPN are under 6 Gyr old.

Age distribution peaks around 2-4 Gyr.

Results align with white dwarf age data.

Abstract

The determination of ages of central stars of planetary nebulae (CSPN) is a complex problem, and there is presently no single method that can be generally applied. We have developed several methods to estimate the ages of CSPN, based both on the observed nebular properties and in some properties of the stars themselves.Our aim is to estimate the ages and the age distribution of CSPN and to compare the derived results with mass and age determinations of CSPN and white dwarfs based on empirical determinations of these quantities. We discuss several methods to derive the age distribution of CSPN, namely, (i) the use of an age-metallicity relation that also depends on the galactocentric distance, (ii) the use of an age-metallicity relation obtained for the galactic disk, and (iii) the determination of ages from the central star masses obtained from the observed nitrogen abundances. We consider a sample of planetary nebulae in the galactic disk, most of which ($\sim$ 69%) are located in the solar neighbourhood, within 3 kpc from the Sun. We estimate the age distribution of CSPN with average uncertainties of 1-2 Gyr, and compare our results with the expected distribution based both on the observed mass distribution of white dwarfs and on the age distribution derived from available mass distributions of CSPN. We conclude most CSPN in the galactic disk have ages under 6 Gyr, and that the age distribution is peaked around 2-4 Gyr.