Planetary nebula distances in Gaia DR2

Abstract

Context. Planetary nebula distance scales often suffer from model-dependent solutions. Model-independent trigonometric parallaxes have been rare. Space-based trigonometric parallaxes are now available for a larger sample using the second Data Release of Gaia. Aims. We aim to derive a high-quality approach for selection criteria of trigonometric parallaxes for planetary nebulae and discuss possible caveats and restrictions in the use of this Data Release. Methods. A few hundred sources from previous distance scale surveys were manually cross-identified with data from the second Gaia Data Release (DR2) because coordinate-based matching does not work reliably. The data were compared with the results of previous distance scales and to the results of a recent similar study that used the first Data Release Gaia DR1. Results. While the few available previous ground-based trigonometric parallaxes as well as those obtained with the Hubble Space Telescope perfectly match the new data sets, older statistical distance scales, reaching larger distances, do show small systematic differences. When we restrict the comparison to the central stars for which the photometric colors of Gaia show a negligible contamination by the surrounding nebula, the difference is negligible for statistical distances based on radio flux, while those derived from Hα surface brightness still show minor differences. The DR2 study significantly improves the previous recalibration of the statistical distance scales using DR1/TGAS.

The MUSE view of the planetary nebula NGC 3132

“…This suggests that this extinction is caused by foreground material, and not intrinsic to the nebula. For the assumed distance here of ∼864 pc (Kimeswenger & Barría 2018), Capitanio et al (2017) reports an E(B − V)∼0.05±0.03 along this line of sight. Our estimated foreground extinction is slightly larger, but consistent with this value, allowing for the existence of plausible inhomogeneities in the foreground ISM, smaller than the resolution of the 3D reddening maps.…”

“…Distances reported for NGC 3132 range between 540 and 1240 pc (Gathier et al 1986;Schönberner et al 2018;Frew 2008;Monteiro et al 2000). In particular, Kimeswenger & Barría (2018), using Gaia DR2, report a distance of ∼824-904 pc. Here, we will adopt the mean, 864 pc, as distance to the nebula.…”

Distance mapping applied to four well-known planetary nebulae and a nova shell

“…For this work, we make use only of the uncertainties provided in the Gaia DR2, as recommended by Luri et al (2018). This means that the errors of the distances derived from the Gaia parallaxes provided in Tables 1-5 are likely larger, as also pointed out by Kimeswenger & Barría (2018).…”

“…These parallaxes will allow us to improve the calibrations of statistical distances. However, better measurements with lower fractional parallax errors are still needed (Stanghellini et al 2017;Kimeswenger & Barría 2018).…”

A Carbon-rich Hot Bubble in the Planetary Nebula NGC 5189

“…The absorbed and intrinsic fluxes in the 0.3-3.0 keV are f X = (5.8 ± 1.7) × 10 −14 erg s −1 cm −2 and F X = (8.2 ± 2.4) × 10 −13 erg s −1 cm −2 . At a distance of 1.68 kpc (Kimeswenger & Barría 2018) this corresponds to an X-ray luminosity of L X = (2.8±0.8)×10 32 erg s −1 . This model is shown in the left panel of Figure 4 as a solid black line.…”