The extinction distances for over a thousand planetary nebulae with Gaia measurements

Abstract

Although Gaia has identified the central stars of planetary nebulae (CSPNe) for about 70% of known Galactic planetary nebulae (PNe), reliable distance estimates remain incomplete, with fewer than one quarter having accurate parallaxes. Meanwhile, classical extinction-distance samples include only about 70 objects, corresponding to 1.8% of the Galactic PN population. We aim to construct a large and homogeneous catalogue of PN distances by refining extinction-distance measurements with Gaia DR3, providing an independent complement to CSPN parallax-based distances. We develop a Gaia-based extinction-distance method by combining an improved blue-edge approach with an extinction-jump model. PN distances are derived from stellar extinction jumps in line-of-sight extinction-distance profiles and are further constrained by comparisons with published distances, the spatial distribution of stars relative to the PN centre, and the PN radius-distance relation. We obtain distances for 1,066 PNe with a median relative uncertainty of 13%, with about 87% of the sample having uncertainties below 20%. The catalogue includes 765 PNe whose CSPN parallaxes have uncertainties greater than 20% and 128 PNe without CSPN parallaxes. This method complements CSPN parallax-based approaches and extends the traditional extinction-based method to higher Galactic latitudes. For PNe with discrepant literature distances, it helps identify the more reliable estimates and assess CSPN identifications. We find a likely misidentification of the reported CSPN for Fr2-36 and analyse 33 PNe with two CSPN candidates, suggesting improved identifications for 15 objects. This catalogue represents the largest homogeneous set of extinction-based PN distances to date and provides a robust benchmark for studies of Galactic structure, PN populations, and interstellar extinction.

Figures (10)

• Figure 1: Left: Stars overlaid on the Digitized Sky Survey image with $R_\mathrm{PN}$ (dashed yellow circle), the CSPN (yellow star), as well as core, nebular, and peripheral sources (red, dark blue, and blue dots). Right: Extinction vs distance.
• Figure 2: Extinction–distance profiles for four PNe with single jumps in the top row and multiple jumps in the bottom row. PN names are labelled at the lower right of each panel. Distance (in kiloparsec) vs extinction $E_\mathrm{G_{BP}, G_{RP}}$ (in magnitude). The source colours are the same as those in Figure 1, and the solid black lines show the fits obtained with our extinction-jump model. PN positions are shown with vertical dashed black lines. The grey points represent ZG25 stars, and the dashed green lines indicate G19 curves. PN distance constraints are shown as diamonds with error bars from GS21 (light green), CW21 (orange), HJ24 (yellow), and F16 (blue). Conventions are consistent throughout.
• Figure 3: Comparison of distances for the tight sample. Distances derived in this work are compared with those from \ref{['CW21']} (orange circles) and \ref{['GS21']} (blue circles). All data points are shown with their associated uncertainties. The solid black line shows $y=x$, while the coloured lines represent the best-fitting relations. The inset displays the distribution of residuals.
• Figure 4: Comparison of our distances with selected individual PN measurements from \ref{['othermethod1']}. The yellow triangles indicate kinematic distances. The blue circles denote other independent methods.
• Figure 5: Step histograms of PN distance distributions for this work (black), CSPN-based samples (blue), and extinction–distance samples (red).