Research Note

VLT/X-shooter Spectroscopy of a dusty planetary nebula discovered with Spitzer/IRS

¹ Leiden Observatory, Leiden University, PO Box 9513, 2300 RA Leiden, The Netherlands
e-mail: oliveira@strw.leidenuniv.nl
² Max-Planck-Institut für Astrophysik, Karl-Schwarschild-Str. 1, 85741 Garching, Germany
³ California Institute of Technology, Division for Geological and Planetary Sciences, MS 150-21, Pasadena, CA 91125, USA
⁴ Max-Planck Institut für Extraterrestrische Physik, Giessenbachstrasse 1, 85748 Garching, Germany
⁵ Research and Scientific Support Department, European Space Agency (ESA-ESTEC), PO Box 299, 2200 AG Noordwijk, The Netherlands

Received: 19 August 2010
Accepted: 26 November 2010

Abstract

As part of a mid-infrared spectroscopic survey of young stars with the Spitzer Space Telescope, an unclassified red emission line object was discovered. Based on its high ionization state indicated by the Spitzer spectrum, this object could either be a dusty supernova remnant (SNR) or a planetary nebula (PN). In this research note, the object is classified and the available spectroscopic data are presented to the community for further analysis. UV/optical/NIR spectra were obtained during the science verification run of the VLT/X-shooter. A large number of emission lines are identified allowing the determination of the nature of this object. The presence of strong, narrow (Δv  ~ 8 – 74 km s^-1) emission lines, combined with very low line ratios of, e.g., [N ii]/Hα and [S ii]/Hα show that the object is a PN that lies at an undetermined distance behind the Serpens Molecular Cloud. This illustrates the potential of X-shooter as an efficient tool for constraining the nature of faint sources with unknown spectral properties or colors.