Barnard’s Merope Nebula (IC 349): An Interstellar Interloper

Abstract

Barnard's Merope Nebula (IC 349) is the optically brightest portion of the diffuse nebulosity that envelops the Pleaides but is not morphologically similar to those nebulae. Knowledge of its true space motion can help clarify whether the object has a kinematic association and possibly a common origin with the Pleiades. Here we report a mean radial velocity result obtained in 1996 from spectra where hel = -44.4 km s-1 and σv = 5.42 km s - 1 (N = 5). The radial velocity result is presented along with recent values for the object's proper motion, yielding its space motion vector. Galactic space velocity components (U, V, W) = (50.6 ± 5.3, -10.3±6.7, 11.3 ± 6.4) km s - 1, referred to the LSR, were calculated for the object. In addition, the region was observed in the near-infrared to determine if a protostellar object is present within the dusty envelope of the nebula; to an equivalent luminosity upper limit of L = 0.23 ± 0.05 L⊙, none was observed. These results suggest that IC 349 is kinematically unrelated to the Pleiades and that it does not harbor a protostellar object in its dusty interior.