Visible to near infrared emission spectra of electron-excited H$_2$

POSTER

Abstract

H$_2$ is the most abundant molecule in the universe and is an active component of star formation. Intense H$_2$ transitions in the visible optical near Infrared (VOIR) spectral region from various vibrational levels have been observed in highly-collimated jets of matter from young stellar objects~[1]. In recent work, we have demonstrated [2] that the gerade series (EF, GK, H$^1\Sigma^{+}_{g}$, I$^1\Pi_{g}$, J$^1\Delta_{g}$...) makes a significant contribution to the UV spectrum of H$_2$ via its cascade spectrum in the VOIR to the $n$~=~$2p\sigma$B and $2p\pi$C states, the upper states of the Lyman and Werner bands, respectively. We present the measured electron-impact-induced emission spectrum of H$_2$ in the VOIR region 700~nm to 950~nm at a spectral resolution of 2~nm (FWHM). A model spectrum of H$_2$ including rovibrational coupling for the strongest band systems is in excellent agreement with observed intensities. \newline [1] Nisini \textit{et al.},A\&A,\textbf{441},159-170,(2005) \newline [2] Liu \textit{et al.},Astrophys.J.Suppl.,\textbf{138},229(2002) and J.Phys.B, \textbf{36},173(2003).

*Work supported by NASA Outer Planet Research, Planetary Atmospheres and Astrophysics Programs.

Authors

  • A. Aguilar

  • G.K. James

  • J.M. Ajello

    • Jet Propulsion Laboratory, Pasadena, CA
  • H. Abgrall

  • E. Roueff

    • LUTH and UMR 8102 du CNRS, Observatoire de Paris, France