Attributing the supernova remnant RCW 89 to the jittering jets explosion mechanism

TL;DR

This paper argues that RCW 89’s two-axis point-symmetric morphology is best explained by the jittering jets explosion mechanism (JJEM), identifying RCW 89 as a separate core-collapse supernova remnant (CCSNR) that may interact with the pulsar wind nebula of PSR B1509-58. By analyzing radio images and comparing to jet-shaped morphologies in other remnants, the work posits two energetic jet pairs shaped RCW 89 and suggests a possible sequential CCSN scenario with interaction between the RCW 89 and PSR B1509-58 remnants. A proposed positive-feedback mechanism for jets—where angular-momentum perturbations sustain jet activity along a fixed plane—helps account for long-lived, aligned jet episodes and the resulting point-symmetric structures. The findings contribute to validating JJEM, expanding the catalog of point-symmetric CCSNRs, and motivating detailed hydrodynamical simulations of jet-driven remnant evolution and inter-remnant interactions.

Abstract

I examine recent radio observations of the supernova remnant (SNR) RCW 89 and identify a point-symmetric morphology composed of two main symmetry axes. I attribute this morphology to a jet-driven explosion in the framework of the jittering jets explosion mechanism (JJEM). To reach this conclusion, I argue that the MSH 15-52 nebula associated with the pulsar PSR B1509-58, the X-ray hand-like-shaped nebula, and RCW 89 are two separate core-collapse supernova (CCSN) remnants that interact with each other. Namely, the nebula SNR G320.4-1.2 contains two CCSN remnants. In essence, I utilize the recent successes of the JJEM to account for the morphologies of point-symmetric CCSN remnants, thereby explaining the morphology of RCW 89 and identifying it as a separate CCSN remnant. I suggest a process by which somewhat more energetic pairs of jets in the JJEM have a positive feedback on the accreted gas onto the newly born neutron star, thereby prolonging the life of the jets and explaining the occurrence of two or three energetic pairs of jets in some CCSNe. This study adds RCW 89 to the growing list of point-symmetric CCSN remnants. The JJEM naturally explains these morphologies as shaped by misaligned pairs of jets that exploded these CCSNe.

Figures (5)

• Figure 1: Images adapted from Zhangetal2025 showing the total intensity radio maps of MSH 15-52 and RCW 89 at 6 cm (left) and 3 cm (right). The radio emission extends to the northeast (Figure \ref{['Fig:RCW89FigureRadioExtend']}). The grayscale bars have units of Jy/beam. Axes are RA and DEC (J2000). I identify and mark several morphological features, as well as the two symmetry axes that I attribute to shaping by two pairs of energetic jets that are part of the pairs of jets that exploded the star in the framework of the JJEM. The red dots in the left panel mark the location of the X-ray knots for which Borkowskietal2020 measure the proper motion.
• Figure 2: A radio continuum image pf G320.4-1.2 at 1.4 GHz adapted from Dubneretal2002. The gray scale is mJy/beam. Contours levels are 5, 10, 20, 30, 60, 90, 120, and 150 mJy/beam. The diagonal lines are Galactic coordinate lines. I added two lines along the same two symmetry axes that I identify in Figure \ref{['Fig:RCW89FigureRadioCen']}. The long symmetry axis is at $14^\circ$ to the Galactic plane.
• Figure 3: An image of the point-symmetric (multipolar) planetary nebula M 1-59 adapted from Hsiaetal2014, who identified the pairs a-a', b-b', and c-c', and attributed the shaping to pairs of jets (bipolar outflows). I added the two green double-lined, two-sided arrows to mark two axes on the morphology of M 1-59.
• Figure 4: Two images of RCW 89 with the two double-sided arrows in the same place and scale as in Figure \ref{['Fig:RCW89FigureRadioCen']}. The images are not on the same scale. (a) An H$\alpha$ image of VPHAS Data created with Aladin (Aladin1Aladin2aladin3). (b) An image processed and produced by Manuel C. Peitsch (Roboscopes at e-EyE Entre Encinas y Estrellas Observatory, Camino de los Molinos, 06340 Fregenal de la Sierra, Spain: https://manuel-astro.ch/) based on original observations by Martin R. Pugh (Observatorio El Sauce, Rio Hurtado, Coquimbo, Chile). Red represents H$\alpha$ emission and blue-green represents [O iii] emission. The arrow on the upper left is along the line of the double-sided arrow of the long axis in the center.
• Figure 5: An image adapted from Borkowskietal2020 showing the proper motion of X-ray bright knots (red dots mark these knots on the radio map in Figure \ref{['Fig:RCW89FigureRadioCen']}). Magenta arrows show the proper motion, and cyan arrows are the velocity components with respect to the pulsar. (The regions encircled in blue were used by them to extract spectra.) Axes are RA with large ticks of $15^{\rm h}13^{\rm m}48^{\rm s}$ to $15^{\rm h}13^{\rm m}12^{\rm s}$ (left to right), and DEC with large ticks of $-59^{\circ}04^{\prime}$, $-59^{\circ}02^{\prime}$, and $-59^{\circ}00^{\prime}$ (bottom up). Red arrow on the lower left is the scale for $0.1^{\prime \prime} ~\rm{yr}^{-1}$. I added the six orange lines from the center of RCW 89 that I identified by the intersection of the two two-sided arrows in Figure \ref{['Fig:RCW89FigureRadioCen']}.