The "twin jet" planetary nebula M2-9

Mario Livio*, Noam Soker

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

32 Scopus citations


We present a model for the structure, temporal behavior, and evolutionary status of the bipolar nebula M2-9. According to this model, the system consists of an asymptotic giant branch (AGB) or post-AGB star and a hot white dwarf companion, with an orbital period of about 120 yr. The white dwarf has undergone a symbiotic nova eruption about 1200 yr ago, followed by a super soft X-ray source phase. The positional shift of the bright knots in the inner nebular lobes is explained in terms of a revolving ionizing source. We show that the interaction between the slow, AGB star's wind and a collimated fast wind from the white dwarf clears a path for the ionizing radiation in one direction, while the radiation is attenuated in others. This results in the mirror-symmetric (as opposed to the more common point-symmetric) shift in the knots. We show that M2-9 provides an important evolutionary link among planetary nebulae with binary central stars, symbiotic systems, and supersoft X-ray sources.

Original languageEnglish
Pages (from-to)685-691
Number of pages7
JournalAstrophysical Journal
Issue number2 PART 1
StatePublished - 10 May 2001
Externally publishedYes


  • Binaries: close
  • Planetary nebulae: general
  • Planetary nebulae: individual (M2-9)
  • Stars: AGB and post-AGB
  • Stars: mass loss
  • X-rays: stars

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