The Supernova 1987A system and its recent evolution - a review

TL;DR

SN 1987A serves as a uniquely detailed laboratory for core-collapse supernova physics, dust formation, and ejecta–circumstellar medium interactions. The past decade, highlighted by JWST observations, reveals a central source photoionizing inner ejecta and provides unprecedented insights into dust masses, molecular inventories, and 3D ejecta geometry, challenging prior formation timescales and supporting substantial late-time dust growth. The paper integrates multiwavelength constraints with advanced 3D hydrodynamical and MHD simulations to map the evolving interplay between fast ejecta, the equatorial ring, and the remnant’s interior, while presenting strong evidence for a central compact object powering central emission; this has profound implications for neutron star birth kicks, PWN viability, and the fate of dust in CCSNe. Looking ahead, coordinated observations with XRISM, JWST, and next-generation optical/IR/radio facilities will further constrain explosion asymmetries, dust processing, and the emergence of the compact object, informing models of dust production in the early universe and the lifecycles of SN remnants.

Abstract

Supernova 1987A was the closest supernova event to be observed in nearly 400 years. The outflowing ejecta from the explosion continues to interact with extended circumstellar material and with the equatorial ring (ER) in the triple ring system, while observations of the system have continued across the whole electromagnetic spectrum. This review mainly focuses on works published over the past ten years on Supernova 1987A and its remnant. These include (a) submillimetre, infrared and X-ray studies of molecules, ions and dust in the ejecta, and (b) infrared, optical and X-ray studies of dust and ionized gas in the ER and in the surrounding circumstellar medium, including their time evolution as the ER is shocked and eroded by the impact of high velocity ejecta. Since 2022, the James Webb Space Telescope has become available for high angular resolution infrared observations of Supernova 1987A and has made significant contributions to both (a) and (b) above. Its discovery of redshifted narrow-line emission from multiple ion species located at the centre of the ejecta strongly requires the presence there of either a cooling hot neutron star, or a pulsar wind nebula, to power the emission.

Figures (14)

• Figure 1: Optical R-band HST images of the equatorial ring taken between 1994 and 2022, showing the appearance, brightening and then fading of 26 hot spots in the ring. The field of view of each image is 2.30$\times$2.15 arcseconds. The spot at approximately 5 o’clock in the early images is a field star. Figure from Tegkelidis et al. 2024 Tegkelidis2024.
• Figure 2: A 2018 (day 11,500) HST/WFC3 F657N image of the triple ring system around SN 1987A and the fainter emission just outside the bright equatorial ring (ER). The F657N filter has a FWHM of 121 Å and encompasses the H$\alpha$ and [N ii] 6584,6548 Å lines. Inside the ER, the faint H$\alpha$ emission from the inner ejecta is produced by external irradiation by X-rays from the shocked ER. The X-ray emission is stronger on the western side of the ER Frank2016. Figure from Larsson et al. 2019 Larsson2019b.
• Figure 3: A 2022 (day 12,974) JWST-NIRCam five-filter composite image of SN 1987A Matsuura2024. The cyan colour of the inner ejecta corresponds to strong emission in the F164N filter, which encompasses [Fe ii] 1.6436 $\mu$m and [Si i] 1.6455 $\mu$m. Image credit: NASA, ESA, CSA, M. Matsuura et al.
• Figure 4: JWST NIRCam F164N image (left) and F356W image (right), with ALMA 315 GHz continuum emission shown as contour lines. The ALMA emission is dominated by nonthermal synchrotron radiation from the ER and dust emission from the ejecta. The ER hotspots and the outer spots detected in the F356W image generally have corresponding spots in the ALMA 315 GHz synchrotron emission. From Matsuura et al. (2024 Matsuura2024)
• Figure 5: JWST NIRSpec volume rendering of the day 12,927 He i 1.083-$\mu$m emission from SN 1987A. The emission from the inner ejecta velocities ($<$4000 km s$^{-1}$) has been omitted. The grey circle shows the position of the ER. From Larsson et al. (2023 Larsson2023).