Massive star formation, outflows, and anomalous H2 emission in Mol 121 (IRAS 20188+3928)

Grace Wolf-Chase*, Kim Arvidsson, Michael Smutko, Reid Sherman

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

3 Scopus citations


We have discovered 12 new molecular hydrogen emission-line objects (MHOs) in the vicinity of the candidate massive young stellar object Mol 121, in addition to five that were previously known. H2 2.12 μm/H 2 2.25 μm flux ratios indicate another region dominated by fluorescence from a photodissociation region, and one region that displays an anomalously low H2 2.12 μm/H2 2.25 μm flux ratio (<1) and coincides with a previously reported deeply embedded source (DES). Continuum observations at 3 mm reveal five dense cores; the brightest core is coincident with the DES. The next brightest cores are both associated with centimeter continuum emission. One of these is coincident with the IRAS source; the other lies at the centroid of a compact outflow defined by bipolar MHOs. The brighter of these bipolar MHOs exhibits [Fe II] emission and both MHOs are associated with CH3OH maser emission observed at 95 GHz and 44 GHz. Masses and column densities of all five cores are consistent with theoretical predictions for massive star formation. Although it is impossible to associate all MHOs with driving sources in this region, it is evident that there are several outflows along different position angles, and some unambiguous associations can be made. We discuss implications of observed H2 2.12 μm/H2 2.25 μm and [Fe II] 1.64 μm/H2 2.12 μm flux ratios and compare the estimated total H2 luminosity with the bolometric luminosity of the region. We conclude that the outflows are driven by massive young stellar objects embedded in cores that are likely to be in different evolutionary stages.

Original languageEnglish (US)
Article number87
JournalAstrophysical Journal
Issue number2
StatePublished - Jan 10 2013


  • ISM: jets and outflows
  • stars: formation
  • stars: massive
  • stars: pre-main sequence
  • stars: protostars

ASJC Scopus subject areas

  • Astronomy and Astrophysics
  • Space and Planetary Science


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