Disk evaporation in a planetary nebula

TL;DR

This study investigates the structure and evolution of the planetary nebula M 2-29, revealing a rotating gas/dust disk, a fast stellar wind, and the effects of ionization on disk dispersal, using HST and VLT observations.

Contribution

It provides new insights into disk evaporation processes in planetary nebulae, highlighting the role of ionization in disk dispersal and the influence of binary modulation.

Findings

Detection of a rotating gas/dust disk within 250 AU

Identification of a fast stellar wind at 1000 km/s

Observation of an expanding equatorial ring at 12 km/s

Abstract

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) using HST imaging and VLT spectroscopy, both long-slit and integral field. The central cavity of M 2-29 is filled with a decreasing, slow wind. An inner high density core is detected, with radius less 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 a source of a very fast wind (1000 km/s). An outer, partial ring is seen in the equatorial plane, expanding at 12 km/s. The azimuthal asymmetry is attributed to mass-loss modulation by an eccentric binary. M 2-29 presents a crucial point in disk evolution, where ionization causes the gas to be lost, leaving a low-mass dust disk behind.