A High-Resolution Spectroscopic Search for the Remaining Donor for Tycho's Supernova

TL;DR

This study uses Hubble and Keck data to analyze stars near Tycho's supernova remnant, finding no evidence of a typical donor star from the single-degenerate supernova model.

Contribution

The paper provides the first comprehensive astrometric and spectroscopic analysis of candidate stars, challenging the single-degenerate progenitor scenario for Tycho's supernova.

Findings

No star exhibits expected SN Ia donor characteristics.

Tycho-B's properties do not fit standard models.

Results suggest the supernova did not originate from a single-degenerate system.

Abstract

In this paper, we report on our analysis using Hubble Space Telescope astrometry and Keck-I HIRES spectroscopy of the central six stars of Tycho's supernova remnant (SN 1572). With these data, we measured the proper motions, radial velocities, rotational velocities, and chemical abundances of these objects. Regarding the chemical abundances, we do not confirm the unusu- ally high [Ni/Fe] ratio previously reported for Tycho-G. Rather, we find that for all metrics in all stars, none exhibit the characteristics expected from traditional SN Ia single-degenerate-scenario calculations. The only possible exception is Tycho-B, a rare, metal-poor A-type star; however, we are unable to find a suitable scenario for it. Thus, we suggest that SN 1572 cannot be explained by the standard single-degenerate model.