WR 42e was first catalogued in 2004 as a member of NGC 3603, numbered 954. It was noted as havingx-ray andHα emission.[7] A detailed study published in 2012 showed that the faint red star was actually a highly obscured (6.4 magnitudes in the visual) hot blue Wolf Rayet star and gave it the name WR 42e.[2] Subsequent changes to the naming conventions for new galactic Wolf–Rayet stars mean it is also called WR 42-1.[6]
WR 42e is located 2.7arcmin west-northwest of the massiveopen clusterHD 97950 at the heart of NGC 3603,[5] corresponding to 6 parsecs at the distance of NGC 3603.[2] This is outside the compact core of the cluster where similar massive luminous stars are found. It is speculated that WR 42e was ejected in an unusualthree-body encounter possibly involving the merger of two of the stars and the ejection of both the resulting objects.[5]
The spectrum of WR 42e shows many characteristics of an OIf* star, such ashydrogenBalmer series absorption lines andemission lines of ionisednitrogen andhelium. The relative strengths of the nitrogen emission lines and the lack of absorption in the468.4 nm helium line indicate a spectral class of O3 If*. However, theHβ line shows a distinct emission wing. AP Cygni profile for this line is a defining character of the OIf*/WN class and so WR 42e is assigned the type O3If*/WN6.[3]
^abcCutri, Roc M.; Skrutskie, Michael F.; Van Dyk, Schuyler D.; Beichman, Charles A.; Carpenter, John M.; Chester, Thomas; Cambresy, Laurent; Evans, Tracey E.; Fowler, John W.; Gizis, John E.; Howard, Elizabeth V.; Huchra, John P.; Jarrett, Thomas H.; Kopan, Eugene L.; Kirkpatrick, J. Davy; Light, Robert M.; Marsh, Kenneth A.; McCallon, Howard L.; Schneider, Stephen E.; Stiening, Rae; Sykes, Matthew J.; Weinberg, Martin D.; Wheaton, William A.; Wheelock, Sherry L.; Zacarias, N. (2003)."VizieR Online Data Catalog: 2MASS All-Sky Catalog of Point Sources (Cutri+ 2003)".CDS/ADC Collection of Electronic Catalogues.2246: II/246.Bibcode:2003yCat.2246....0C.Archived from the original on 2021-04-21. Retrieved2024-12-26.
