Abstract
Planetary nebulae (PNe) are expected to have a ∼105 K interface layer between the ≥106 K inner hot bubble and the ∼104 K optical nebular shell. The PN structure and evolution, and the X-ray emission, depend critically on the efficiency of the mixing of material at this interface layer. However, neither its location nor its spatial extent have ever been determined. Using high-spatial resolution HST STIS spectroscopic observations of the N v λλ 1239,1243 lines in the Cat's Eye Nebula (NGC 6543), we have detected this interface layer and determined its location, extent, and physical properties for the first time in a PN. We confirm that this interface layer, as revealed by the spatial distribution of the N v λ1239 line emission, is located between the hot bubble and the optical nebular shell. We estimate a thickness of 1.5 × 1016 cm and an electron density of ∼200 cm-3 for the mixing layer. With a thermal pressure of ∼2 × 10-8 yncm-2, the mixing layer is in pressure equilibrium with the hot bubble and ionized nebular rim of NGC 6543.
Original language | English (US) |
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Article number | L19 |
Journal | Astrophysical Journal Letters |
Volume | 822 |
Issue number | 1 |
DOIs | |
State | Published - May 1 2016 |
Keywords
- Outflows
- Planetary nebulae: general
- Planetary nebulae: individual (NGC 6543)
- Stars: winds
- X-rays: ISM
ASJC Scopus subject areas
- Astronomy and Astrophysics
- Space and Planetary Science