We present submillimeter spectral line and dust continuum polarization observations of a remarkable hot core and multiple outflows in the high-mass star-forming region W43-MM1 (G30.79 FIR 10), obtained using the Submillimeter Array (SMA). A temperatu
re of $sim$ 400 K is estimated for the hot-core using CH$_3$CN (J=19-18) lines, with detections of 11 K-ladder components. The high temperature and the mass estimates for the outflows indicate high-mass star-formation. The continuum polarization pattern shows an ordered distribution, and its orientation over the main outflow appears aligned to the outflow. The derived magnetic field indicates slightly super-critical conditions. While the magnetic and outflow energies are comparable, the B-field orientation appears to have changed from parsec scales to $sim$ 0.1 pc scales during the core/star-formation process.
The spectral energy distributions (SEDs), spanning the mid-infrared to millimeter wavelengths, of a sample of 13 high-mass protostellar objects (HMPOs) were studied using a large archive of 2-D axisymmetric radiative transfer models. Measurements fro
m the Spitzer GLIMPSE and MIPSGAL surveys and the MSX survey were used in addition to our own surveys at millimeter and submillimeter wavelengths to construct the SEDs, which were then fit to the archive of models. These models assumed that stars of all masses form via accretion and allowed us to make estimates for the masses, luminosities and envelope accretion rates for the HMPOs. The models fit the observed SEDs well. The implied envelope accretion rates are high, $approx 10^{-2.5} msun/yr$, consistent with the accretion-based scenario of massive star formation. With the fitted accretion rates and with mass estimates of up to $sim 20 msun$ for these objects, it appears plausible that stars with stellar masses $M_{ast} > 20 msun$ can form via accretion.
We present arcsecond-scale mid-ir photometry (in the 10.5 micron N band and at 24.8 microns), and low resolution spectra in the N band (R~100) of a candidate high mass protostellar object (HMPO) in IRAS 18151-1208 and of two HMPO candidates in IRAS 2
0343+4129, IRS 1 and IRS 3. In addition we present high resolution mid-ir spectra (R~80000) of the two HMPO candidates in IRAS 20343+4129. These data are fitted with simple models to estimate the masses of gas and dust associated with the mid-ir emitting clumps, the column densities of overlying absorbing dust and gas, the luminosities of the HMPO candidates, and the likely spectral type of the HMPO candidate for which [Ne II] 12.8 micron emission was detected (IRAS 20343+4129 IRS 3). We suggest that IRAS 18151-1208 is a pre-ultracompact HII region HMPO, IRAS 20343+4129 IRS 1 is an embedded young stellar object with the luminosity of a B3 star, and IRAS 20343+4129 IRS 3 is a B2 ZAMS star that has formed an ultracompact HII region and disrupted its natal envelope.
