Bibcode
Corradi, R. L. M.; García-Rojas, J.; Jones, D.; Rodríguez-Gil, P.
Bibliographical reference
The Astrophysical Journal, Volume 803, Issue 2, article id. 99, 13 pp. (2015).
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4
2015
Journal
Citations
99
Refereed citations
72
Description
The discrepancy between abundances computed using optical recombination
lines and collisionally excited lines is a major unresolved problem in
nebular astrophysics. Here, we show that the largest abundance
discrepancies are reached in planetary nebulae with close binary central
stars. We illustrate this using deep spectroscopy of three nebulae with
a post common-envelope (CE) binary star. Abell 46 and Ou 5 have
O2+/H+ abundance discrepancy factors larger than
50, and as high as 300 in the inner regions of Abell 46. Abell 63 has a
smaller discrepancy factor around 10, which is still above the typical
values in ionized nebulae. Our spectroscopic analysis supports previous
conclusions that, in addition to “standard” hot
({{T}e} ∼ 104 K) gas, there exists a colder
({{T}e} ∼ 103 K), ionized component that is
highly enriched in heavy elements. These nebulae have low ionized
masses, between 10‑3 and 10‑1
M⊙ depending on the adopted electron densities and
temperatures. Since the much more massive red giant envelope is expected
to be entirely ejected in the CE phase, the currently observed nebulae
would be produced much later, during post-CE mass loss episodes when the
envelope has already dispersed. These observations add constraints to
the abundance discrepancy problem. We revise possible explanations. Some
explanations are naturally linked to binarity such as, for instance,
high-metallicity nova ejecta, but it is difficult at this stage to
depict an evolutionary scenario consistent with all of the observed
properties. We also introduce the hypothesis that these nebulae are the
result of tidal destruction, accretion, and ejection of Jupiter-like
planets.
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