Massive star formation occurs in the interior of giant molecular clouds and proceeds through many stages. In this work, we focus on massive young stellar objects (MYSOs) and ultracompact H ii regions (UCH ii), where the former are enshrouded in dense envelopes of dust and gas, the latter of which has begun dispersing. By selecting a complete sample of MYSOs and UCH ii from the Red MSX Source (RMS) survey database, we combine Planck and IRAS data and build their spectral energy distributions. With these, we estimate the physical properties (dust temperatures, mass, luminosity) of the sample. Because the RMS database provides unique solar distances, it also allows the instantaneous star formation efficiency (SFE) to be investigated as a function of Galactocentric radius. We find that the SFE increases between 2 and 4.5 kpc, where it reaches a peak, likely in correspondence with the accumulation of molecular material at the end of the Galactic bar. It then stays approximately constant up to 9 kpc, after which it linearly declines, in agreement with predictions from extragalactic studies. This behavior suggests the presence of a significant amount of undetected molecular gas at R _G > 8 kpc. Finally, we present diagnostic colors that can be used to identify sites of massive star formation.

巨大的恒星形成发生在巨大分子云的内部，并经历了许多阶段。在这项工作中，我们专注于大质量年轻恒星物体 (MYSOs) 和超紧凑 H ii区域 (UCH ii )，其中前者被密集的尘埃和气体包裹，后者已经开始分散。通过选择完整的 MYSO 和 UCH 样本ii从 Red MSX Source (RMS) 调查数据库中，我们结合了普朗克和 IRAS 数据并构建了它们的光谱能量分布。通过这些，我们可以估计样品的物理特性（粉尘温度、质量、光度）。由于 RMS 数据库提供了独特的太阳距离，它还允许将瞬时恒星形成效率 (SFE) 作为半乳心半径的函数进行研究。我们发现 SFE 在 2 到 4.5 kpc 之间增加，达到峰值，这可能与银河棒末端分子材料的积累相对应。然后它保持大约恒定直到 9 kpc，之后它线性下降，与河外研究的预测一致。这种行为表明在R处存在大量未检测到的分子气体 _G > 8 kpc。最后，我们提出了可用于识别大质量恒星形成地点的诊断颜色。