Thursday

We present medium-resolution (R~7000) NIR echelle spectroscopic data for 36 Massive YSOs selected from the Red MSX Source (RMS) survey. This is the largest sample at this resolution at these wavelengths of MYSOs to date. The spectra are characterised mostly by emission from H recombination lines and accretion diagnostic lines.
Photospheric absorption lines are visible in one object, allowing for the first time a direct estimation of the spectral type of an MYSO. The best fit is that of an early A supergiant, which can be understood through swelling up caused by fast accretion, as predicted by recent star formation models.
Mass accretion rates from Brackett gamma agree with results for low and intermediate-mass YSOs, providing tentative evidence for massive star formation theories based on scaling of low-mass case scenarios.
Finally, we obtain clues about the wind emission geometry through studying velocity-resolved HI line ratios.