Detection of Interstellar C~I and C~IV within 26~pc of the Sun
Session 114 -- Multi-Phase Interstellar Medium
Display presentation, Saturday, January 15, 9:30-6:45, Salons I/II Room (Crystal Gateway)

## [114.14] Detection of Interstellar C~I and C~IV within 26~pc of the Sun

F.C. Bruhweiler (Catholic U.), A.M. Smith (GSFC/LASP), G. Perry \& C.-H. Lyu (Catholic Univ.)

Data for interstellar features seen in the spectrum of $\alpha$ Gru (B7~IV; d = 26~pc) have recently been obtained by the Goddard High Resolution Spectrograph aboard the Hubble Space Telescope . These data have been acquired using both the G160M medium (R$\sim$~25,000) and Echelle-B high (R$\sim$~80,000) spectral resolution configurations. These data are of high signal-to-noise ratios, ranging from 100 to 300. This line-of-sight ($l=350^{o}, b=152^{o}$) intersects the main body of the Local Cloud and the detection of excited fine-structure absorption in C II~$\lambda$1335.7 indicates particle number densities in excess of $\approx$~5~cm$^{-3}$, much higher than the n$\sim$~0.1 cm$^{-3}$ deduced at the Sun. These data also show the first detection of both interstellar C~I~$\lambda$1657 and C~IV~$\lambda\lambda$1548,1550 in the local ISM. The detection of C~IV is inconsistent with photoionization from the hot stars of the nearby Sco-Cen association and with thermal conduction in a cloud interface. The most likely explanation implies that the C~IV is formed in gas still in a recombination phase. Such ionized gas should be present due to the recent supernova event (10$^{5-6}$~yrs) that gave rise to the local Loop I radio structure.