# Get ready for Gaia: cool white dwarfs in common proper motion with Tycho stars

## TL;DR

This paper explores the use of Gaia DR1 data combined with the Tycho catalogue and ground-based surveys to identify cool white dwarfs in common proper motion with Tycho stars, aiming to improve distance estimates for faint white dwarfs.

## Contribution

It introduces a method to find faint cool white dwarfs in common proper motion with Tycho stars using Gaia DR1 and ground-based data, enhancing distance measurements for these elusive objects.

## Key findings

- Identification of candidate faint cool white dwarfs in common proper motion with Tycho stars.
- Demonstration of CPM as a tool for estimating distances to very faint white dwarfs.
- Integration of Gaia DR1 with ground-based surveys to improve white dwarf studies.

## Abstract

We discuss the Gaia Data Release 1 (September 2016) and preliminary work on maximising the benefit for cool white dwarf (WD) science in advance of the full parallax catalogue which will appear around one year later in DR2. The Tycho catalogue is used in conjunction with the all-sky ground based astrometric/photometric SuperCOSMOS Sky Survey in order to identify candidate faint common proper motion objects to the Tycho stars. Gaia DR1 is supplemented by the Tycho-Gaia Astrometric Solution catalogue containing some 2 million parallaxes with Hipparcos-like precision for Tycho stars. While hotter, brighter WDs are present in Tycho, cooler examples are much rarer (if present at all) and CPM offers one method to infer precision distances for a statistically useful sample of these very faint WDs.