A new perspective on the interstellar cloud surrounding the Sun from UV
  absorption line results
  We offer a new, more inclusive, picture of the local interstellar medium,
where it is composed of a single, monolithic cloud that surrounds the Sun in
all directions. Our study of velocities based on Mg II and Fe II ultraviolet
absorption lines indicates that the cloud has an average motion consistent with
the velocity vector of gas impacting the heliosphere and does not behave like a
rigid body: gas within the cloud is being differentially decelerated in the
direction of motion, and the cloud is expanding in directions perpendicular to
this flow, much like the squashing of a balloon. The outer boundary of the
cloud is in average 10 pc away from us but is highly irregular, being only a
few parsecs away in some directions, with possibly a few extensions up to 20
pc. Average H I volume densities vary between 0.03 and 0.1 cm-3 over different
sight lines. Metals appear to be significantly depleted onto grains, and there
is a steady increase in this effect from the rear of the cloud to the apex of
motion. There is no evidence that changes in the ionizing radiation influence
the apparent abundances. Additional, secondary velocity components are detected
in 60 % of the sight lines. Almost all of them appear to be interior to the
volume holding the gas that we identify with the main cloud. Half of the sight
lines exhibit a secondary component moving at about - 7.2 km/s with respect to
the main component, which may be the signature of an implosive shock
propagating toward the cloud's interior.
