1. Joint Institute for Laboratory Astrophysics - University of Colorado, 2. Wesleyan University
In August 2012, Voyager 1 crossed the heliopause, becoming the first human-made object to exit the Solar System. This milestone signifies the beginning of an important new era for local interstellar medium (LISM) discoveries. We present measurements of the structure and composition of the LISM by using high-resolution Hubble Space Telescope spectra of nearby stars that lie along the same lines of sight as the respective paths of the Voyager spacecraft. We provide a comprehensive inventory of LISM absorption in the near-ultraviolet (2600-2800) and the far-ultraviolet (1200-1500). The LISM absorption profiles are used to make comparisons between each pair of closely spaced (<15) sight lines. With these fits, we can make measurements of the physical properties of the LISM, including temperature, turbulence, electron density, and dust composition. As both HST and Voyager reach the end of their lifetimes, we now have the opportunity to synthesize their respective independent and complementary observations, combining in-situ measurements with the shortest possible line-of-sight measurements to provide an unprecedented study of the galactic ISM surrounding the Sun.
We would like to acknowledge NASA HST Grant GO-13658 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.