Unveiling the structure of the planetary nebula M 2-48:

Kinematics and physical conditions

¹ Instituto de Astrofísica de Canarias, c/Vía Láctea s/n, 38200 La Laguna, Tenerife, Spain e-mail: luislm,cel@ll.iac.es
² Observatoire de Paris, DEMIRM, UMR 8540 du CNRS, 61 avenue de l'Observatoire, 75014 Paris, France
³ Instituto de Astronomía, UNAM, Km 103, Carretera Tijuana-Ensenada, 22860 Ensenada, B.C., Mexico e-mail: jal,vazquez@astrosen.unam.mx
⁴ Instituto de Ciencias Nucleares, Circuito de la Investigación Científica, 04510 Cd. Universitaria, D.F., Mexico e-mail: raga@astroscu.unam.mx
⁵ Institut d'Estudis Espacials de Catalunya and Instituto de Ciencias del Espacio (CSIC), Edifici Nexus, c/ Gran Capitá 2-4, 08034, Barcelona, Spain e-mail: torrelles@ieec.fcr.es
⁶ Instituto de Astrofísica de Andalucía, CSIC, c/ Sancho Panza s/n, 18008 Granada, Spain e-mail: lfm@iaa.es
⁷ Astronomy Department, University of Manchester, Jodrell Bank, Macclesfield, Cheshire SK11 9DL, UK
⁸ Instituto de Astronomía, UNAM, Circuito de la Investigación Científica, 04510 Cd. Universitaria, D.F., Mexico e-mail: lorenzo@astroscu.unam.mx

Corresponding author: L. López-Martín, luis.lopezmartin@obspm.fr

Received: 28 February 2002
Accepted: 27 March 2002

Abstract

The kinematics and physical conditions of the bipolar planetary nebula M 2-48 are analysed from high and low dispersion long-slit spectra. Previous CCD narrow-band optical observations have suggested that this nebula is mainly formed by a pair of symmetric bow-shocks, an off-center semi-circular shell, and an internal bipolar structure. The bipolar outflow has a complex structure, characterised by a series of shocked regions located between the bright core and the polar tips. There is an apparent kinematic discontinuity between the bright bipolar core and the outer regions. The fragmented ring around the bright bipolar region presents a low expansion velocity and could be associated with ejection in the AGB-PN transition phase, although its nature remains unclear. The chemical abundances of the central region are derived, showing that M 2-48 is a type I planetary nebula (PN).