Astronomy and Astrophysics – Astronomy
Scientific paper
Dec 1997
adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=1997aas...191.5116s&link_type=abstract
American Astronomical Society, 191st AAS Meeting, #51.16; Bulletin of the American Astronomical Society, Vol. 29, p.1298
Astronomy and Astrophysics
Astronomy
Scientific paper
The VUV spectra of many B-type giant and supergiant stars whose lines-of-sight are not intersected by dark interstellar clouds were recorded in the range 1000-1200 Angstroms by the Copernicus satellite in the mid-70's and in the range 900-1160 Angstroms with the ORFEUS-1 spectrometer during the September '93 mission of the Discovery space shuttle. From inspection of these spectra, which vary little from star to star, one concludes that the observed relative absorption intensities of individual vibronic components of the H_2 Lyman-band (B<-X) and Werner-band (C<-X) systems cannot at all be comprehended on the basis of linear spectroscopy. Furthermore, the /sim100 cm(-1) - wide linewidths of the strong emission bands seen in these spectra cannot be explained in terms of normal H_2 fluorescence. We explain both of these apparent anomalies by proposing that the H_2 molecules are located in a cloud that is close enough to the star to allow the latter's VUV blackbody continuum to induce broadband stimulated Raman scattering (SERS). A natural consequence of SERS is the presence of lightwave coherence. Under such conditions, further coherent coupling or wave mixing is expected. In particular, four-wave parametric oscillation (FWPO) occurring on many of the H_2 levels can be invoked to explain both the regions of absorption and the dominant emission peaks appearing in these spectra. We show that the frequencies, intensities, and linewidths of these spectral features are consistent with coherent optical processes in H_2.
Glownia James H.
Sorokin Peter P.
No associations
LandOfFree
Evidence for Nonlinear Generation of VUV Light by Four-Wave Parametric Oscillation (FWPO) in H_2-Containing Clouds Near B-Type Supergiants does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.
If you have personal experience with Evidence for Nonlinear Generation of VUV Light by Four-Wave Parametric Oscillation (FWPO) in H_2-Containing Clouds Near B-Type Supergiants, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Evidence for Nonlinear Generation of VUV Light by Four-Wave Parametric Oscillation (FWPO) in H_2-Containing Clouds Near B-Type Supergiants will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-1174394