Chandra observations of the planetary nebula IC 4593

The Advanced CCD Imaging Spectrometer (ACIS-S) camera on board the Chandra X-ray Observatory has been used to discover a hot bubble in the planetary nebula (PN) IC 4593, the most distant PN detected by Chandra so far. The data are used to study the distribution of the X-ray-emitting gas in IC 4593 and to estimate its physical properties. The hot bubble has a radius of similar to 2 arcsec and is found to be confined inside the optically bright innermost cavity of IC 4593. The X-ray emission is mostly consistent with that of an optically thin plasma with temperature kT approximate to 0.15 keV (or T-X approximate to 1.7 x 10(6) K), electron density n(e) approximate to 15 cm(-3) , and intrinsic X-ray luminosity in the 0.3-1.5 keV energy range L-X = 3.4 x 10(30) erg s(-1). A careful analysis of the distribution of hard (E >0.8 keV) photons in IC4593 suggests the presence of X-ray emission from a point source likely associated with its central star (CSPN). If this was the case, its estimated X-ray luminosity would be L-X,(CSPN) = 7 x 10(29) erg s(-1), fulfilling the log(L-X, (CSPN)/L-bol) approximate to -7 relation for self-shocking winds in hot stars. The X-ray detection of the CSPN helps explain the presence of high-ionization species detected in the ultraviolet spectra as predicted by stellar atmosphere models. © 2020 The Author(s).JAT and MAG are supported by the Universidad Nacional Autonoma de Mexico (UNAM) Direccion General de Asuntos del Personal Academico (DGAPA) PAPIIT projects IA100318 and IA100720. MAG acknowledges support from grant PGC2018102184-B-I00, co-funded with FEDER funds. LB and YHC acknowledge support from NASA grant Chandra GO2-13024B. YHC acknowledges the research grant 108-2112-M-001-045 from the Ministry of Science and Technology (MOST) of Taiwan. This work has made extensive use of the NASA's Astrophysics Data System. Based on observations made with the NASA/ESA Hubble Space Telescope, and obtained from the Hubble Legacy Archive, which is a collaboration between the Space Telescope Science Institute (STScI/NASA), the Space Telescope European Coordinating Facility (ST-ECF/ESA) and the Canadian Astronomy Data Centre (CADC/NRC/CSA)