High Spatial Resolution Spectroscopy of W51 IRS2E and IRS2W:
Two Very Massive Young Stars in Early Formation Stages

C. L. Barbosa (1), R. D. Blum (2), P. S. Conti (3), A. Damineli (4) and E. Figueredo (5)

(1) IP&D-UNIVAP, (2) NOAO GSC, (3) JILA U. Colorado, (4) IAG - USP, (5) Open University

We present $K$-band spectra of the near infrared counterparts to IRS2E and
IRS2W which is associated with the ultracompact HII region W51d, both of them
embedded sources in the Galactic compact HII region W51 IRS2. The high spatial
resolution observations were obtained with the laser guide star facility and
Near infrared Integral Field Spectrograph (NIFS) mounted at the Gemini North
observatory. The spectrum of the ionizing source of W51d shows the photospheric
features NIII (21155 AA) in emission and HeII (21897 AA) in absorption which
lead us to classify it as an young O3 type star. We detected CO overtone in
emission at 23000 AA in the spectrum of IRS2E, suggesting that it is a
massive young object still surrounded by an accretion disc, probably
transitioning from the hot core phase to an ultracompact HII region.

Reference: ApJL, in press
Status: Manuscript has been accepted

Weblink: http://arxiv.org/abs/0803.3853


Email: cassio@univap.br