Multi-Cycle HST Treasury Program for STIS: Mapping the Galactic Environment of the Sun

TL;DR

This paper advocates for a multi-cycle HST program to map the physical properties of nearby interstellar clouds via ultraviolet absorption lines, enhancing understanding of the Sun's galactic environment over time.

Contribution

It proposes a comprehensive survey plan using STIS to study local interstellar material, emphasizing the need for multiple HST cycles for detailed analysis.

Findings

Planned survey will determine ionization, temperature, density, and velocity of nearby interstellar clouds.

Mapping will inform on the Sun's historical galactic environment.

Utilizes ultraviolet absorption lines for detailed interstellar medium characterization.

Abstract

Interstellar clouds form the cosmic "ecosystem" through which the Sun moves. Understanding the physical properties of nearby interstellar material, in sufficient detail to evaluate historical variations in the solar galactic environment, requires a survey of ultraviolet interstellar absorption lines towards stars within 20 pc with the STIS spectrometer. A complete survey would yield ionization, temperature, density and velocity for nearby interstellar clouds, and would require a large number of Hubble Space Telescope orbits spaced over several cycles. This note was submitted as a "white paper" to the Space Telescope Science Institute in support of multi-cycle treasury programs.