Protostars and Planets VI, Heidelberg, July 15-20, 2013

Poster 1G016

The small-scale structure of OMC-2 FIR 4: Interferometric observations of an intermediate-mass protocluster

Lopez-Sepulcre, Ana (IPAG)
Taquet, Vianney (NASA)
Sanchez-Monge, Alvaro (INAF-Arcetri)
Kama, Mihkel (University Leiden)
Ceccarelli, Cecilia (IPAG)
Dominik, Carsten (University Amsterdam)
Caux, Emmanuel (IRAP)
Shimajiri, Yoshito (NRO)

Intermediate-mass stars are an important ingredient of our Galaxy and a key to understanding how high- and low-mass stars form in clusters. One of the closest known young intermediate-mass protoclusters is OMC-2 FIR 4, which is located at a distance of 420 pc in Orion. This region is one of the few where the complete 500-2000 GHz spectrum has been observed with the heterodyne spectrometer HIFI on board the Herschel satellite, and unbiased spectral surveys at 0.8, 1, 2, and 3 mm have been obtained with the JCMT and IRAM 30-m telescopes. In order to investigate the small-scale morphology of OMC-2 FIR 4 and aid in interpretation of the single-dish line profiles already in our hands, we imaged the region using the IRAM Plateau de Bure Interferometer and the Very Large Array of the NRAO. The resulting maps have an angular resolution that allows us to resolve structures down to 1 arcsec, which is equivalent to  400 AU. Our observations reveal three spatially resolved sources within OMC-2 FIR 4, of one or several solar masses each, with hints of further unresolved substructure within them. One of them may be associated with a young B3-B4 star that dominates the overall luminosity output of the region. In short, our interferometric observations show the complexity of the intermediate-mass protocluster OMC-2 FIR 4, where multiple cores, chemical di fferentiation, and an ionised region all coexist within an area of only 10000 AU.

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