Planetary nebula or symbiotic Mira? Near infrared colours mark the difference*
Institut für Astrophysik der Leopold-Franzens-Universität Innsbruck, Technikerstr. 25, 6020 Innsbruck, Austria ()
Corresponding author: S. Schmeja, firstname.lastname@example.org
Accepted: 17 August 2001
Nebulae around symbiotic Miras look very much like genuine planetary nebulae, although they are formed in a slightly different way. We present near infrared photometry of known and suspected symbiotic nebulae obtained with the Deep Near Infrared Southern Sky Survey (DENIS). We demonstrate that the near infrared colours are an excellent tool to distinguish symbiotic from genuine planetary nebulae. In particular we find that the bipolar planetary nebulae M 2-9 and Mz 3 are in fact symbiotic Miras. Further observations on prototype symbiotic Miras prove that the proposed classification scheme works generally.
Key words: planetary nebulae: general / binaries: symbiotic / stars: AGB and post-AGB / stars: winds, outflows
© ESO, 2001