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“Taking A Second Look at Interstellar Carbon” Dr. Ulysses Sofia Whitman College |
| Carbon is arguably the most important element in interstellar dust. However, its apparent abundance in grains has been labeled the Carbon Crisis because it is insufficient to produce the extinction of light that is observed toward distant objects. Interstellar carbon abundance determinations are difficult to make because the dominant ion state in the neutral interstellar medium produces only very weak and very strong absorption features for the density regimes that can be explored. Until recently it has been argued that only the weak transitions could produce carbon abundances of sufficient quality to interpret carbon's role in dust. We, however, have devised a method for using the strong carbon transitions to determine reliable C abundances. These results suggest that the Carbon Crisis may not exist, and may have come about as the result of poor atomic constants associated with the weak transition. |