When a massive star explodes, it tends to leave chaos behind. Shocks sweep past, cosmic rays are accelerated and nearby gas and dust are reshaped. It is surprising, then, to find wreckage of such a blast hosting newborn stars . The ALMA , dated 13 July 2026, described exactly that inside RX J1713.7-3946 , a remnant left by a massive star that, according to the release, exploded about 1,600 years ago.



Two hot cores inside the remnant RX J1713.7-3946




This remnant is called RX J1713.7-3946. Takashi Shimonishi from Niigata University, along with his team, directed the Atacama Large Millimeter/submillimeter Array (ALMA) towards this remnant to look out for hot cores, which are warm and dense shells of molecular gases that surround baby stars. Astronomers studying records from China’s Jin dynasty have long linked the remnant to a “guest star” seen in 393 AD, though a 2012 study in The Astronomical Journal questioned how well the two match.




The results appear in the study Survival of Molecular Complexity under Recent Supernova Feedback: Detection of Hot Cores in RX J1713.7-3946, by Takashi Shimonishi, Hidetoshi Sano, Kenji Furuya and Yoko Oya, published in ALMA detected two hot cores, which the ALMA press release describes as the first detection of hot molecular cores in a supernova remnant. Both show rich molecular emission, including a wide variety of organic molecules . The paper reports that ALMA identified two hot cores, HC1 and HC2, inside the remnant’s X-ray shell, both tied to Class I intermediate-mass protostars. Focusing on HC1, the authors detected a suite of carbon-, oxygen-, nitrogen-, sulphur- and silicon-bearing species and their excitation analysis put the gas at roughly 10⁷ cm⁻³, under 500 au across, and above 100 K. The authors argue the shocks may have reached the material too recently to erase that chemistry or that amplified magnetic fields may be shielding it from enhanced cosmic rays.



Chemistry that survived the blast




Organic molecules may form due to chemical reactions on the surface of dust grains in molecular clouds where conditions are extremely cold. Once a young star forms and heats its surroundings, that ice evaporates into gas, which is how hot cores are detected.



Analysis of HC1 shows that its complex organic molecules are present in proportions similar to those in hot cores in star-forming regions untouched by nearby supernovae. Such an outcome was not guaranteed, since the destruction or synthesis of organic molecules could have occurred in response to energetic particles and shock waves.



Why the molecules may have lasted




Two explanations are suggested by the scientists. First is the timing issue. The supernova shock may have reached the cores only recently, leaving too little time for energetic particles to significantly alter their chemistry. The second explanation has something to do with the magnetic field. The shock wave from the supernova supposedly increases the magnetic field in the cloud, which in turn prevents the rays from penetrating into the denser parts. Shimonishi suggests that the observations indicate how newly formed stars may remain protected within their surrounding environments, despite the harsh conditions. But whether this is usually happening is still unknown.



A star-forming region flagged back in 2010




Star formation in this region was suspected long before ALMA looked. The 2010 study Star-forming Dense Cloud Cores in the TeV Gamma-ray SNR RX J1713.7-3946, led by Hiroaki Sano and also published in , examined molecular cloud cores in the remnant. The paper’s abstract says a core labelled peak C shows clear evidence of active star formation, including bipolar outflow. They say the core survived the shockwave and remains within the remnant and that simulations suggest a dense clump can withstand shock erosion. In the Shimonishi paper, the two fields of study for ALMA are explained as being peak C and D of the aforementioned research paper.



What it could mean for the Solar System




The finding also has broader implications. Niigata University’s announcement says that the Solar System could have originated from a place that was heavily affected by neighbouring supernovae. In addition to this, the press release from ALMA states that the chemically rich core of RX J1713.7-3946 can provide a valuable analogy in researching how the influence of supernovae on star and planet-forming ingredients works. Shimonishi also stated that places that are capable of having complex organic molecules, which are potentially important for prebiotic chemistry, may be more diverse than has been known before.