Habitable Worlds Observatory: The Nature of the First Stars

TL;DR

The paper advocates for using the Habitable Worlds Observatory to study the first stars through high-resolution UV spectroscopy, aiming to detect low-metallicity stars and analyze their elemental compositions to understand early cosmic history.

Contribution

It proposes a novel application of the Habitable Worlds Observatory for characterizing first stars and their metal abundances via UV spectroscopy, expanding observational capabilities beyond Hubble.

Findings

Potential to confirm surviving low-mass zero-metallicity stars.

Ability to detect a wider range of elements in low-metallicity stars.

Enhanced discovery space for faint stars in the Milky Way and nearby systems.

Abstract

We present the science case for characterizing the nature of the first stars using the Habitable Worlds Observatory (HWO). High-resolution ultraviolet (UV) spectroscopy with the HWO has the potential to confirm any surviving low-mass zero-metallicity first stars by placing unprecedented low limits on their metal abundances. It also has the potential to substantially increase the number of elements detectable in the spectra of known long-lived low-mass stars, which exhibit extremely low metal abundances that reveal the metals produced by the first stars. Elements important for this science case with UV transitions include C, Mg, Al, Si, P, S, Sc, V, Cr, Mn, Fe, Co, Ni, Cu, and Zn. HWO would expand the discovery space when compared with the Hubble Space Telescope by enabling high-resolution UV spectroscopy for much fainter stars throughout the Milky Way and neighboring stellar systems.