Absolute spectrophotometry of northern compact planetary nebulae

¹ Isaac Newton Group of Telescopes, Ap. de Correos 321, 38700 Sta. Cruz de la Palma, Canary Islands, Spain e-mail: rcorradi@ing.iac.es
² UCLA, Department of Physics and Astronomy, Los Angeles, CA, 90095, USA e-mail: saw@astro.ucla.edu
³ Dipartimento di Astronomia e Scienza dello Spazio, Universitá di Firenze, L.go E. Fermi 5, 50125 Firenze, Italy e-mail: mariop@arcetri.astro.it

Received: 19 November 2002
Accepted: 14 March 2005

Abstract

We present medium-dispersion spectra and narrowband images of six northern compact planetary nebulae (PNe): BoBn 1, DdDm 1, IC 5117, M 1–5, M 1–71, and NGC 6833. From broad-slit spectra, total absolute fluxes and equivalent widths were measured for all observable emission lines. High signal-to-noise emission line fluxes of Hα, Hβ, [Oiii], [Nii], and HeI may serve as emission line flux standards for northern hemisphere observers. From narrow-slit spectra, we derive systemic radial velocities. For four PNe, available emission line fluxes were measured with sufficient signal-to-noise to probe the physical properties of their electron densities, temperatures, and chemical abundances. BoBn 1 and DdDm 1, both type IV PNe, have an Hβ flux over three sigma away from previous measurements. We report the first abundance measurements of M 1–71. NGC 6833 measured radial velocity and galactic coordinates suggest that it is associated with the outer arm or possibly the galactic halo, and its low abundance () may be indicative of low metallicity within that region.