Open AccessX‐ray emission by a shocked fast wind from the central stars of planetary nebulae
Author(s) -
Akashi Muhammad,
Soker Noam,
Behar Ehud
Publication year - 2006
Publication title -
monthly notices of the royal astronomical society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.058
H-Index - 383
eISSN - 1365-2966
pISSN - 0035-8711
DOI - 10.1111/j.1365-2966.2006.10234.x
Subject(s) - physics , planetary nebula , astrophysics , stars , astronomy , x ray , nebula , optics
We calculate the X‐ray emission from the shocked fast wind blown by the central stars of planetary nebulae (PNe) and compare with observations. Using spherically symmetric self‐similar solutions, we calculate the flow structure and X‐ray temperature for a fast wind slamming into a previously ejected slow wind. We find that the observed X‐ray emission of six PNe can be accounted for by shocked wind segments that were expelled during the early‐PN phase, if the fast wind speed is moderate, v 2 ∼ 400–600 km s −1 , and the mass‐loss rate is a few times 10 −7 M ⊙ yr −1 . We find, as proposed previously, that the morphology of the X‐ray emission is in the form of a narrow ring inner to the optical bright part of the nebula. The bipolar X‐ray morphology of several observed PNe, which indicates an important role of jets, rather than a spherical fast wind, cannot be explained by the flow studied here.