IC 349: Barnard's Merope Nebula

Abstract

view Abstract Citations (9) References (45) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS IC 349: Barnard's Merope Nebula Herbig, G. H. Abstract IC 349 is the brightest area in the Pleiades reflection nebulosity, by a factor of about 15. Discovered visually by Barnard in 1890, it is a difficult object because it is only about 30" from 23 Tau, of V=4.2. It is fan-shaped with the axis pointing very nearly toward 23 Tau. its blue color and the fact that its spectrum appears identical to that of the star shows that it also is a reflection nebula. The general Pleiades nebulosity is the result of a chance encounter between the cluster and a molecular cloud at a relative cross motion of about 12 km s-1 It is proposed that the semistellar object at the head of IC 349 is part of that cloud and is being dissipated in the radiation field of 23 Tau as it approaches that star. The relative velocity vector is obtained from the proper motion and radial velocity of the cluster, and the CO radial velocity of the nearby Tau-Aur clouds; the proper motion of IC 349 is inferred from the proper motions of the cloud T Tauri stars. The shape of the fan of IC 349 is compatible with a model in which small dust particles ejected from the nucleus are being swept backward by the combined effects of radiation pressure from 23 Tau and drag exerted by intercluster gas. it is unknown whether the nucleus is a dust-shrouded pre-main-sequence star or a dense concentration of gas and dust several hundred A.U. in diameter. Publication: The Astronomical Journal Pub Date: March 1996 DOI: 10.1086/117869 Bibcode: 1996AJ....111.1241H Keywords: ISM: INDIVIDUAL: IC 349 full text sources ADS | data products SIMBAD (4)