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Full-Text Articles in Physical Sciences and Mathematics
Diffuse Band Profiles In The Rho Ophiuchi Cloud, C Gregory Seab, Theodore P. Snow
Diffuse Band Profiles In The Rho Ophiuchi Cloud, C Gregory Seab, Theodore P. Snow
Physics Faculty Publications
High-resolution, high signal-to-noise ratio line profiles are presented for the 5780 and 5797 A diffuse interstellar bands toward six stars in the Rho Oph dark cloud. Target stars were chosen to exhibit a wide range of interstellar grain properties, as measured by grain polarization and far-UV extinction. The extreme case of the heavily reddened star HD 147889 is included; this star has one of the highest known lambdamax values, indicative of unusually large grains. Despite the differences in the grain properties, the line profiles and central wavelengths for the 5780 A band were found to be essentially identical for …
The Physics Of Grain-Grain Collisions And Gas-Grain Sputtering In Interstellar Shocks, A G. Tielens, C F. Mckee, C G. Seab, D J. Hollenbach
The Physics Of Grain-Grain Collisions And Gas-Grain Sputtering In Interstellar Shocks, A G. Tielens, C F. Mckee, C G. Seab, D J. Hollenbach
Physics Faculty Publications
Grain-grain collisions and ion sputtering destroy dust grains in interstellar shocks. An analytical theory is developed for the propagation of shock waves in solids driven by grain-grain collisions, which compares very favorably with detailed numerical calculations. This theory is used to determine the fraction of a grain vaporized by a grain-grain collision. Our results predict much less vaporization of colliding grains in interstellar shocks than previous estimates. This theory can also be used to determine the fraction of a colliding grain that melts, shatters, or undergoes a phase transformation to a higher density phase. In particular, the latter two processes …
Interstellar Gas And Dust In The Young Cluster Ic 348, Theodore P. Snow, Margaret Murray Hanson, C Gregory Seab, Jon M. Saken
Interstellar Gas And Dust In The Young Cluster Ic 348, Theodore P. Snow, Margaret Murray Hanson, C Gregory Seab, Jon M. Saken
Physics Faculty Publications
We have completed a multiband absorption- and emission-line study of a star embedded in the young cluster IC 348, to determine the environmental effect of star formation on the interstellar medium (ISM) local to the region. The hottest and youngest star in IC 348 is BD+31°643, a B5 V star which samples the inner bright nebular region. The nearby star o Per, which lies only 8 to the north and is thought to lie beyond IC 348, samples the gas and dust which has not been processed by very recent star formation. We speculate that the ISM throughout the region …
On The System Of Diffuse Interstellar Bands At 5844 And 5850 Å, J Krelowski, Theodore P. Snow, J Papaj, C G. Seab, B Wszolek
On The System Of Diffuse Interstellar Bands At 5844 And 5850 Å, J Krelowski, Theodore P. Snow, J Papaj, C G. Seab, B Wszolek
Physics Faculty Publications
Two neighboring diffuse interstellar bands (DIBs) at 5844 and 5850 Å are shown to be of different origin. The presence or absence of the 5844 DIB is related to the ratio of the two prominent DIBs at 5780 and 5797 Å as well as to the nature of the ultraviolet extinction curve. The 5844 Å DIB is very sensitive to the extinction, being completely absent in cases where the far-UV extinction is low. This suggests that the carrier is destroyed by photons having energies above 11 or 12 eV. The 5850 Å DIB correlates very well with the well-studied DIB …
Spatial Correlation Between Ch, Cn And The Diffuse Interstellar Band Carriers, J Krelowski, T P. Snow, C G. Seab, J Papaj
Spatial Correlation Between Ch, Cn And The Diffuse Interstellar Band Carriers, J Krelowski, T P. Snow, C G. Seab, J Papaj
Physics Faculty Publications
Observations are presented of the diffuse interstellar bands at 5780 and 5797 A and of the ultraviolet lines of CH and CN in the light of six bright stars which lie behind isolated interstellar clouds. It is found that CN and CH are only present when the 5797 band is deeper than the 5780 one. Comparisons with satellite measurements of the UV extinction show that the shape of the extinction curve is linked to the same band ratio in these stars. The results support a previous suggestion that the various components of the absorption spectrum of an isolated cloud (the …
Diffuse Band Profiles In The Spectrum Of Hd 29647: Evidence For A Molecular Origin?, Theodore P. Snow, C G. Seab
Diffuse Band Profiles In The Spectrum Of Hd 29647: Evidence For A Molecular Origin?, Theodore P. Snow, C G. Seab
Physics Faculty Publications
High signal-to-noise ratio spectra have been obtained of the diffuse interstellar bands at 5780 and 5797 Å in the spectrum of HD 29647, a heavily reddened star within or behind a portion of the Taurus dark cloud complex. The observations were made using the coudé spectrograph on the Canada-France-Hawaii Telescope. The Reticon detector combined with the coudé spectrograph and excellent observing conditions allowed S/N ratios as high as 200 for this star, which was V=8.37 and E(B–V)=1.03. In two separate exposures both bands were found to be narrower and weaker than normal values for …