EDP Sciences
Free access
Volume 379, Number 1, November III 2001
Page(s) L17 - L20
Section Letters
DOI http://dx.doi.org/10.1051/0004-6361:20011345

A&A 379, L17-L20 (2001)
DOI: 10.1051/0004-6361:20011345

VLT-ISAAC 3-5 $\mu$m spectroscopy as a new tool for investigating H $_\mathsf{2}$ emission in protostellar jets

T. Giannini, B. Nisini, F. Vitali and D. Lorenzetti

Osservatorio Astronomico di Roma, via Frascati 33, 00040 Monte Porzio, Italy
    e-mail: bruni, vitali, dloren@coma.mporzio.astro.it

(Received 17 September 2001 / Accepted 26 September 2001 )

We report 3-5 $\mu$m IR spectroscopy obtained with VLT-ISAAC on the IRS17 molecular hydrogen jet in the Vela-D Molecular Cloud. Together with H2 emission lines from the v = 1 rovibrational state, the spectra show several pure rotational lines of the fundamental state with excitation temperature up to ~22 000 K. We show how theoretical rotation diagrams indicate these lines as unique both to probe the presence of collisionally excited gas in NLTE conditions and to infer the gas density.

Key words: stars: formation -- infrared: ISM: lines -- ISM: jets and outflows -- ISM: individual objects: Vela clouds

Offprint request: T. Giannini, teresa@coma.mporzio.astro.it

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