A new large high latitude cone-like far-IR nebula

Abstract

We present a new isolated interstellar nebula (RA = 08 h 27 m ,D ec =+ 25 ◦ 54 � (J2000); � = 197. 8, b =+ 31. ◦ 6) found at 100 µm and 60 µm on IRAS maps. It has dimensions of ∼140 � × 70 � and a cone-like shape, suggesting interaction with ambient matter or external radiation. The nebula contains 2 bright condensations (“nuclei”) and several prominent filaments, the latter being approximately parallel to each other. We carried out preliminary studies based on IRAS data and the Palomar Observatory Sky Survey and found that there are no hints of star formation in the nebula. The nebula’s long axis is almost parallel to the Galactic plane. A shaping due to the nebula’s motion through the interstellar medium might be not a sufficient reason in this case. We have discussed this possibility by applying results of Reynolds number hydrodynamics. During a search for possible stellar candidates for shaping this nebula we noted a remarkable position of one of the very few nearby (D ≈ 0.36 kpc) pulsars known at about this latitude: PSR B0823+26. This pulsar is projected at the tip of the nebula and its proper motion is approaching along the long axis (∼180 ◦ to the direction of the cone) of the nebula. The true cause for the shaping of the nebula, which was coined Skeleton Nebula by us, however remains unknown.