Three-dimensional distribution of ejecta in Supernova 1987A at 10 000 days

TL;DR

This study provides the most detailed 3D maps of ejecta in Supernova 1987A at 10,000 days, revealing large-scale asymmetries and substructures that inform explosion models and dust properties.

Contribution

It presents new 3D spectral and imaging maps of multiple emission lines in SN 1987A, including the first detailed 3D maps for several key elements at this epoch.

Findings

Large-scale north-south asymmetry resembling a broken dipole

Stable [Si I]+[Fe II] flux and morphology over ten years

Substructures in H-alpha and [Si I]+[Fe II] lines at 200-1000 km/s

Abstract

Due to its proximity, SN 1987A offers a unique opportunity to directly observe the geometry of a stellar explosion as it unfolds. Here we present spectral and imaging observations of SN 1987A obtained ~10,000 days after the explosion with HST/STIS and VLT/SINFONI at optical and near-infrared wavelengths. These observations allow us to produce the most detailed 3D map of H-alpha to date, the first 3D maps for [Ca II] \lambda \lambda 7292, 7324, [O I] \lambda \lambda 6300, 6364 and Mg II \lambda \lambda 9218, 9244, as well as new maps for [Si I]+[Fe II] 1.644 \mu m and He I 2.058 \mu m. A comparison with previous observations shows that the [Si I]+[Fe II] flux and morphology have not changed significantly during the past ten years, providing evidence that it is powered by 44Ti. The time-evolution of H-alpha shows that it is predominantly powered by X-rays from the ring, in agreement with previous findings. All lines that have sufficient signal show a similar large-scale 3D structure, with a north-south asymmetry that resembles a broken dipole. This structure correlates with early observations of asymmetries, showing that there is a global asymmetry that extends from the inner core to the outer envelope. On smaller scales, the two brightest lines, H-alpha and [Si I]+[Fe II] 1.644 \mu m, show substructures at the level of ~ 200 - 1000 km/s and clear differences in their 3D geometries. We discuss these results in the context of explosion models and the properties of dust in the ejecta.