Confirming the First Low-Metallicity Wolf-Rayet Dust Factory

In our current understanding of dust-forming sources, we cannot account for the observed quantities of dust in local and high-redshift galaxies. Recent studies indicate that the answer to this long-standing mystery may include carbon-rich Wolf-Rayet (WC) stars. Theoretical models predict that WC stars can even be significant sources of dust at sub-solar metallicity, consistent with the lower metallicity environment of galaxies beyond the local Universe. However, there is a dearth of known dust-forming WC binaries at sub-solar metallicity to verify the model predictions.

New results from the Spitzer Space Telescope have identified an IR-luminous outburst named SPIRITS 19q, which exhibited highly efficient dust production likely linked to a dust-formation episode from an extragalactic WC system in the subsolar metallicity outskirts of the nearby galaxy NGC 2403. This tentative link between SPIRITS 19q and the WC star has not yet been confirmed due to the unresolved nature of the luminous stellar cluster coincident with 19q. In this proposal, we request 6.74 hours of spectroscopic imaging observations with the NIRSpec IFU between 0.6 - 5.3 microns at R ~ 100 in order to confirm dust formation from the WC star by spatially resolving and identifying the near-IR (1 - 2 micron) spectroscopic features associated with the WC star and the mid-IR (3 - 5 micron) emission associated with the SPIRITS 19q. Efficient dust-formation from just one WC system can have a significant impact on the ISM, and confirmation of efficient dust formation from this WC star would validate the theoretical models that demonstrate WC stars as significant sources of dust at sub-solar metallicity.