573 research outputs found
Ultraviolet observations of close-binary and pulsating nuclei of planetary nebulae; Winds and shells around low-mass supergiants; The close-binary nucleus of the planetary nebula HFG-1; A search for binary nuclei of planetary nebulae; UV monitoring of irregularly variable planetary nuclei; and The pulsating nucleus of the planetary nebula Lo 4
A brief summary of the research highlights is presented. The topics covered include the following: binary nuclei of planetary nebulae; other variable planetary nuclei; low-mass supergiants; and other IUE-related research
NSV 11749: Symbiotic Nova, Not a Born-Again Red Giant
NSV 11749 is a little-studied variable star, discovered by W. J. Luyten,
which had a long-duration outburst around the year 1903, reaching blue
magnitude 12.5 at maximum. Following the outburst, it has apparently been
quiescent at about blue magnitude 17 for the past century. It was recently
suggested that NSV 11749 may have been a low- or intermediate-mass star that
underwent a final helium shell flash, making it temporarily a "born-again" red
giant. If so, it would be only the fourth known member of this class, along
with V605 Aql, FG Sge, and V4334 Sgr. However, our newly obtained optical and
near-IR spectra of the object show that it is instead a symbiotic binary, with
strong Balmer and He I-II emission lines, combined with a cool red-giant
companion of spectral type M1-2 III. The 1903 outburst was most likely a
symbiotic nova event, of which less than a dozen are known at present.Comment: 13 pages, 3 figures, Accepted for publication in PAS
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