Bibcode
Mendez, R. H.; Manchado, A.; Herrero, A.
Referencia bibliográfica
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.
Fecha de publicación:
12
1988
Número de citas
11
Número de citas referidas
11
Descripción
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.