A stronger He II 4686 in the spectrum of the planetary nebula NGC 6572

Mendez, R. H.; Manchado, A.; Herrero, A.
Bibliographical reference

Astronomy and Astrophysics (ISSN 0004-6361), vol. 207, no. 1, Dec. 1988, p. L5 to L7. Research supported by the Instituto de Astrofisica de Canarias.

Advertised on:
12
1988
Number of authors
3
IAC number of authors
2
Citations
11
Refereed citations
11
Description
On a recent spectrogram of the planetary nebula NGC 6572 the authors have found He II 4686 clearly in emission. They review previous descriptions of the spectrum and conclude that He II 4686 is stronger than 20 years ago. They briefly discuss the possible implications of this result, and suggest a careful monitoring of several planetary nebulae.