Disk evaporation in a planetary nebula^*

¹ Centrum Astronomii UMK, ul.Gagarina 11, 87-100 Torun, Poland e-mail: Krzysztof.Gesicki@astri.uni.torun.pl
² Jodrell Bank Centre for Astrophysics, School of Physics & Astronomy, University of Manchester, Oxford Road, Manchester M13 9PL, UK e-mail: a.zijlstra@manchester.ac.uk
³ European Southern Observatory, Karl Schwarzschildstrasse 2, Garching 85748, Germany
⁴ Nicolaus Copernicus Astronomical Center, ul. Rabiańska 8, 87-100 Torun, Poland

Received: 24 October 2009
Accepted: 20 January 2010

Abstract

Aims. Binary interactions are believed to be important contributors to the structures seen in planetary nebulae (PN), and the sole cause of the newly discovered compact dust disks. The evolution of these disks is not clear, nor are the binary parameters required for their creation.

Methods. Using HST imaging and VLT spectroscopy, both long-slit and integral field, we study the Galactic bulge planetary nebula M 2-29 for which a 3-year eclipse event of the central star has been attributed to a dust disk.

Results. The central PN cavity of M 2-29 is being filled with a decreasingly, slow wind. An inner high density core is detected, of radius smaller than 250 AU, interpreted as a rotating gas/dust disk with a bipolar disk wind. The evaporating disk is argued to be the source of the slow wind. The central star is the source of a very fast wind (~10³  km s^-1). An outer, partial ring is seen in the equatorial plane, expanding at 12 km s^-1. The azimuthal asymmetry is attributed to mass-loss modulation by an eccentric binary. A crucial point in disk evolution is represented by M 2-29 where ionization causes the gas to be lost, leaving a low-mass dust disk behind.