Bibcode
Jones, D.; Wesson, R.; García-Rojas, J.; Corradi, R. L. M.; Boffin, H. M. J.
Bibliographical reference
Monthly Notices of the Royal Astronomical Society, Volume 455, Issue 3, p.3263-3272
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1
2016
Citations
66
Refereed citations
48
Description
We present new optical spectra of the nearby, bright, planetary nebula
NGC 6778. The nebula has been known to emit strong recombination lines
for more than 40 years but this is the first detailed study of its
abundances. Heavy element abundances derived from recombination lines
are found to exceed those from collisionally excited lines by a factor
of ˜20 in an integrated spectrum of the nebula, which is among the
largest known abundance discrepancy factors. Spatial analysis of the
spectra shows that the abundance discrepancy factor is strongly,
centrally peaked, reaching ˜40 close to the central star. The
central star of NGC 6778 is known to be a short-period binary, further
strengthening the link between high nebular abundance discrepancy
factors and central star binarity.