We present two epochs of lambda 6 cm Very Large Array (VLA) maps of the planetary nebulae NGC 7027 and BD+30-3639 with subarsecond angular resolution. By taking advantage of the high dynamic range possible with the VLA as well as the almost 6 yr time baseline between the two epochs, we have constructed difference maps that show the signature characteristic of the radial expansion of the ionization front surrounding the nebulae. We have combined these results with the Doppler expansion velocities to estimate the distance to both objects. Our results indicate that DNGC 7027 = 703 +/- 95 pc and DBD+30 = 2680 +/- 810 pc.
No takes yet. Share an insight, caveat, or question.
Hajian et al. (1993) studied this question.
Synapse has enriched 5 related papers. Consider them for comparative context: