Sakurai's object: the ionized nebula at radio wavelengths

S. P. S. Eyres, M. F. Bode, A. M. S. Richards

Research output: Contribution to journalArticlepeer-review


Sakurai's object (V4334 Sgr) is a planetary nebula nucleus which is undergoing its final helium shell flash. This is the first of these rare and important events to be observable with non-optical instruments. We report the first radio detection, using a short (2-h) observation with the Very Large Array (VLA) at 4.86 GHz. The radio emission structure is coincident with the 34-arcsec diameter planetary nebula seen in optical emission lines. We find a statistical distance ∼ 3.8 ± 0.6 kpc, with a range of 1.9 < D < 5.3 kpc, depending on the planetary nebula (PN) mass. While we have no direct evidence for a new (post-flash) stellar wind, we estimate an upper limit to the mass-loss rate due to any such wind of 1.7 × 10−7 M⊙ yr−1. The number of emitting knots in the radio-visible nebula indicates an electron density of ∼ 2 × 108 m−3 in those knots, and a total emitting ionized mass of ∼ 0.15 M⊙, at an assumed distance of 3.8 kpc. The radio flux density indicates an Hβ flux of ∼ 6 × 10−16 W m−2, suggesting an extinction E(B − V) ∼ 1.15, comparable with reddening estimates in the direction of V4334 Sgr.
Original languageEnglish
Pages (from-to)905-909
JournalMonthly Notices of the Royal Astronomical Society
Issue number3
Publication statusPublished - 1 Jul 1998


  • stars: AGB and post-AGB
  • circumstellar matter
  • stars: individual: Sakurai's Object
  • stars: individual: V4334 Sgr
  • stars: late-type
  • radio continuum: stars


Dive into the research topics of 'Sakurai's object: the ionized nebula at radio wavelengths'. Together they form a unique fingerprint.

Cite this