Towards a Complete Census of CSPNe in Gaia

• DOI: 10.5281/zenodo.2634247
• Publication Date: 2019-04-01
• Authors: N. Chornay; N. A. Walton
• Keywords: catalogue matching; planetary nebulae; 01 natural sciences; 0105 earth and related environmental sciences

Planetary Nebulae (PNe) are a brief stage through which low and intermediate mass stars pass towards the end of their evolution, between red giant and white dwarf. They are excellent probes of the chemo-kinematical structure of the Milky Way. Accurate distances to PNe are necessary to make any sort of meaningful astrophysical characterisation, from their nebula size and lifetimes to their central star luminosities. The Gaia mission provides an unprecedented opportunity to better understand these objects through measurements of the trigonometric parallaxes of their central stars. Taking full advantage of these measurements requires accurate cross matching of PN catalogues and Gaia sources. As the size of both catalogues increases, it becomes impractical and inadvisable to do this manually. We present an automated method based on the classic likelihood ratio technique that bootstraps from available data and considers both the relative positions and Gaia colours of central star candidates. Applying this method to the HASH PN Catalogue and to Gaia DR2, we find over 1000 likely central star matches, twice as many as in previous works, while also rejecting significant numbers of potential contaminants. The subsample of these matches with the most accurate parallaxes will allow us to make comparisons to distance scales in literature as well as to simultaneously trace central star and nebular evolution.