Chandra observations of the planetary nebula IC 4593
Abstract
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 ∼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 ≈ 0.15 keV (or TX ≈ 1.7 × 106 K), electron density ne ≈ 15 cm-3, and intrinsic X-ray luminosity in the 0.3-1.5 keV energy range LX = 3.4 × 1030 erg s-1. A careful analysis of the distribution of hard (E >0.8 keV) photons in IC 4593 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 LX, CSPN = 7 × 1029 erg s-1, fulfilling the log(LX, CSPN/Lbol) ≈ -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.
- Publication:
-
Monthly Notices of the Royal Astronomical Society
- Pub Date:
- May 2020
- DOI:
- 10.1093/mnras/staa1024
- arXiv:
- arXiv:2004.04542
- Bibcode:
- 2020MNRAS.494.3784T
- Keywords:
-
- stars: low-mass;
- stars: winds;
- outflows;
- planetary nebulae: general;
- planetary nebulae: IC 4593;
- X-rays: general;
- Astrophysics - Solar and Stellar Astrophysics;
- Astrophysics - Astrophysics of Galaxies
- E-Print:
- 6 pages, 4 figures