Dynamos in Asymptotic-Giant-Branch Stars As the Origin of Magnetic Fields Shaping Planetary Nebulale

Abstract

Planetary nebulae are thought to be formed when a slow wind from the progenitor giant star is overtaken by a subsequent fast wind generated as the star enters its white dwarf stage${}^1$. A shock forms near the boundary between the winds, which creates a relatively dense shell that provides the characteristic appearance of a planetary nebula. A spherically symmetric wind will produce a spherically symmetric shell, yet over half of known planetary nebulae are not spherical; rather, they are elliptical or bipolar in shape${}^2$. While a magnetic field could launch and collimate a bipolar outflow, the origin of such a field has hitherto been unclear, as previous work suggested that a field could not be generated${}^3$. Here we show that an asymptotic-giant-branch (AGB) star can indeed generate a strong magnetic field, in a dynamo at the interface between a rapidly rotating core and the more slowly rotating envelope of the star. The field is strong enough to shape the bipolar outflows that produce the observed bipolar planetary nebulae. Magnetic braking of the stellar core during this process may also explain the puzzlingly${}^4$ slow rotation of most white dwarf stars.

13 pages, LaTex, one ps fig.; published in Nature

References in corpus (11)

• MHD Stellar and Disk Winds: Application to Planetary Nebulae
• A New Spin on the Problem of HB Gaps: Stellar Rotation along the Blue Horizontal Branch of Globular Cluster M13
• Disk Formation by AGB Winds in Dipole Magnetic Fields
• Disk Winds and the Accretion--Outflow Connection
• Overcoming the Back Reaction on Turbulent Motions in the Presence of Magnetic Fields
• Models of OH Maser Variations in U Her
• Outflows from magnetic rotators I. Inner structure
• The Morphological and Structural Classification of Planetary Nebulae
• Magnetic collimation of the solar and stellar winds
• Molecular line observations of proto-planetary nebulae
• Hubble Space Telescope Imaging of the Young Planetary Nebula GL 618

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