Constructing a Survey of the Local Interstellar Medium using Hubble Spectra
Abstract
Light from distant objects transverses through interstellar clouds comprised of warm, partially ionized gas causing extinction. The Sun itself is embedded in a complex amalgamation of these clouds that can be observed only through sensitive absorption studies in the ultraviolet. We analyze high resolution spectra obtained by the Space Telescope Imaging Spectrograph (STIS) on the Hubble Space Telescope (HST) for 37 local (≪100 pc) stars with the intention to categorize absorption features caused by local interstellar medium (LISM) clouds along the line of sight. In particular, we analyze the absorption features of MgII, FeII, and MnII due to their relatively high abundance in the LISM and particularly strong absorption. We detect one to five discrete LISM features for each individual sightline; the higher the number of features correlating to the longer distance transversed by the sightline. Each component's spectral absorption feature is fit with a Voigt profile that determines the cloud's radial velocity, column density, and Doppler parameter, the final values of which are compared to a dynamical model of the LISM by Redfield and Linsky (2008) in an attempt to produce a more complete survey of all LISM clouds. The results of this survey will significantly improve our understanding of the three-dimensional morphology of the LISM, and support future investigations into the fundamental measurements of the LISM. We acknowledge support for this project through NASA HST Grant GO-13332 awarded by the Space Telescope Science Institute, which is operated by the Association of Universities for Research in Astronomy, Inc., for NASA, under contract NAS 5-26555, and a student research grant from the Wesleyan Math and Science Scholars (WesMaSS).
- Publication:
-
American Astronomical Society Meeting Abstracts #235
- Pub Date:
- January 2020
- Bibcode:
- 2020AAS...23536807K