Jones, D.; Boffin, H. M. J.; Rodríguez-Gil, P.; Wesson, R.; Corradi, R. L. M.; Miszalski, B.; Mohamed, S.
Bibliographical reference
Astronomy and Astrophysics, Volume 580, id.A19, 14 pp.
Advertised on:
8
2015
Journal
Citations
56
Refereed citations
49
Description
We present a study of Hen 2-155 and Hen 2-161, two planetary nebulae
which bear striking morphological similarities to other planetary
nebulae known to host close-binary central stars. Both central stars are
revealed to be photometric variables while spectroscopic observations
confirm that Hen 2-155 is host to a double-eclipsing,
post-common-envelope system with an orbital period of
3h33m making it one of the shortest period binary
central stars known. The observations of Hen 2-161 are found to be
consistent with a post-common-envelope binary of period ~1 day. A
detailed model of the central star of Hen 2-155 is produced, showing the
nebular progenitor to be a hot, post-AGB remnant of approximately 0.62
M⊙, consistent with the age of the nebula, and the
secondary star to be an M dwarf whose radius is almost twice the
expected zero age main sequence radius for its mass. In spite of the
small numbers, all main-sequence companions, of planetary nebulae
central stars, to have had their masses and radii constrained by both
photometric and spectroscopic observations have also been found to
display this "inflation". The cause of the "inflation" is uncertain but
is probably related to rapid accretion, immediately before the recent
common-envelope phase, to which the star has not yet thermally adjusted.
The chemical composition of both nebulae is also analysed, showing both
to display elevated abundance discrepancy factors. This strengthens the
link between elevated abundance discrepancy factors and close binarity
in the nebular progenitor.
Full Tables 2-5, and 7 are only available at the CDS via anonymous ftp
to http://cdsarc.u-strasbg.fr
(ftp://130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/580/A19
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