Planetary Nebulae in the eROSITA eRASS1 Catalog

Some planetary nebulae (PNs) host X-ray-emitting hot bubbles shaped by stellar wind interactions and/or harbor X-ray-emitting central stars due to accretion, shocks within their fast stellar winds, or even chromospheric emission from binary companions. In both cases, the properties of the X-ray emission critically probe late stages of stellar evolution for such low- and intermediate-mass stars. While extant Chandra and XMM-Newton observations have detected X-ray emission in PNs, the numbers known remain very small (∼40) compared to the overall Galactic PNs population (∼4000). We have initiated a project aimed at increasing the sample of known PNs with X-ray emission using both current and new space-based X-ray telescopes, such as the Einstein probe. To further investigate their X-ray properties to elucidate what drives current X-ray PN detections, we have cross-searched the SRG eROSITA-DE eRASS1 source catalog and the Hong Kong (HASH) PNs Database. Five known X-ray PNs have been detected (A30, NGC 2392, NGC 3242, NGC 5315, and LoTr 5), two new X-ray PNs are revealed (IC 1297 and NGC 2867), one (K 1–27) is removed from previous X-ray compilations, and another 11 previously detected X-ray emitting PNs are not recovered. A comparison of the X-ray flux of detected and undetected X-ray PNs reveals that eROSITA eRASS1 is sensitive to PNs with X-ray fluxes larger than ≈2 × 10 −14 erg cm −2 s −1 . The frequency of occurrence is ≃0.5% among the 1430 HASH True PNs in the eRASS1 footprint.