Very Cold and Massive Cores near ISOSS J18364−0221: Implications for the Initial Conditions of High‐Mass Star Formation

We report the discovery of two very cold and massive molecular cloud cores inthe region ISOSS J18364-0221. The object has been identified by a systematicsearch for very early evolutionary stages of high-mass stars using the 170micron ISOPHOT Serendipity Survey (ISOSS). Submm continuum and molecular linemeasurements reveal two compact cores within this region. The first core has atemperature of 16.5 K, shows signs of ongoing infall and outflows, has no NIRor MIR counterpart and is massive enough (M ~ 75 M_sun) to form at least one Ostar with an associated cluster. It is therefore considered a candidate for agenuine high-mass protostar and a high-mass analog to the Class 0 objects. Thesecond core has an average gas and dust temperature of only ~ 12 K and a massof M ~ 280 M_sun. Its temperature and level of turbulence are below the valuesfound for massive cores so far and are suggested to represent the initialconditions from which high-mass star formation occurs.Comment: 9 pages, 6 figures, accepted for publication in the Astrophysical Journa