The VLT Images a "Rectangular" Planetary Nebula

IC 4406 is a planetary nebula with an unusual, almost "rectangular" shape. It is located in the southern constellation Lupus (the Wolf). The distance is somewhat uncertain, possibly around 5,000 light-years. Like the Butterfly Nebula (cf. VLT UT1 First Light Photo No. 4), IC 4406 belongs to the class of bipolar nebulae. However, the dark and dusty central band (the "disc-like structure") is less pronounced in this object and the internal structure is more uniform. The different colours correspond to regions of different composition and physical properties.

This is a combination of two 5-min B (blue) exposures (seeing 0.95 arcsec), two 5-min V (green-yellow) exposures (0.90 arcsec), and one 5-min and two 2-min R (red) exposures (0.70 to 0.90 arcsec) with the VLT Test Camera. Individual frames were flat-fielded and cleaned for cosmics before colour combination; there was no further image processing. The field measures 1.5 x 1.5 arcmin. North is to the upper right; East is to the upper left.