The first polluted white dwarf from Gaia DR2: the cool DAZ GaiaJ1738-0826

TL;DR

This paper reports the discovery of GaiaJ1738-0826, the first metal-polluted white dwarf identified via Gaia DR2, highlighting its spectral features and similarities to previously known polluted white dwarfs.

Contribution

It introduces the first Gaia DR2-based identification of a metal-polluted white dwarf, demonstrating Gaia's capability to find such objects.

Findings

GaiaJ1738-0826 shows strong Ca II absorption lines.

It resembles the first confirmed metal-polluted hydrogen atmosphere white dwarf.

The discovery showcases Gaia DR2's potential for identifying polluted white dwarfs.

Abstract

We present the first metal-polluted single white dwarf star identified through Gaia DR2. GaiaJ1738-0826, selected from color and absolute magnitude cuts in the Gaia DR2 data, was discovered to have strong Ca~II absorption in initial spectroscopic characterization at Lick Observatory. Notably, GaiaJ1738-0826 resembles in many ways the first confirmed metal-polluted hydrogen atmosphere white dwarf, the DAZ G74-7.