Study Finds Primordial Black Holes Passing Through White Dwarfs Could Trigger Type Ia Supernovae
A new Astrophysical Journal study finds primordial black holes tunneling through white dwarfs could explain some Type Ia supernovae and Milky Way chemical patterns.
Overview
A team of astrophysicists has found that hypothetical primordial black holes passing through white dwarf stars could trigger some of the Type Ia supernovae observed across the Milky Way, and that the chemical fingerprints left behind by such explosions help explain abundance patterns seen in stars throughout the galaxy, according to a study published in The Astrophysical Journal on June 15, 2026. The research, led by Shing-Chi Leung of SUNY Polytechnic Institute, builds on an earlier 2025 paper by the same team and marks the second installment of their investigation into this proposed explosion channel, according to Kavli IPMU.
What We Know
Primordial black holes (PBHs) are hypothetical relics thought to have formed from fluctuations in matter density during the universe’s inflationary period, and they are considered one possible candidate for dark matter, the invisible material that accounts for about 90% of matter in the universe by mass, according to Kavli IPMU. The specific class examined in this study is known as “asteroid-mass” PBHs; according to the paper’s own abstract on arXiv, these have a mass between roughly 4×10⁻¹⁷ and 4×10⁻¹² solar masses and “could be the major component of dark matter in the cosmic mass budget.” Universe Today describes that range as spanning from roughly the mass of a large asteroid up to a small moon or dwarf planet.
The proposed mechanism works when a PBH passes through a white dwarf — the dense stellar remnant left behind after a low-mass star exhausts its fuel, according to ScienceDaily. As the black hole moves through the star, its gravity generates tidal heating inside the white dwarf. Once the surrounding material reaches a threshold temperature of roughly 0.5 billion Kelvin, it triggers uncontrolled nuclear burning that, if the burning region is large enough, sets off a full thermonuclear runaway and a Type Ia supernova explosion, according to Universe Today. As the paper itself puts it, “The infall of these PBH into a white dwarf could be one triggering mechanism of Type Ia supernovae (SNe Ia),” as quoted by Universe Today from the paper text.
The new paper, titled “Primordial Black Hole Triggered Type Ia Supernovae. II. Comparison with Supernova Remnants and Galactic Chemical Evolution,” follows up on a first paper the team published in 2025 showing that PBH-triggered explosions can produce Type Ia supernovae closely resembling those from standard explosion models, according to Kavli IPMU. For the new study, the researchers compared their models against three well-studied supernova remnants — Tycho, Kepler, and 3C 397 — plus two nearby supernovae, SN 2011fe and SN 2012cg, and the chemical abundances of stars across the Milky Way, according to Kavli IPMU.
By examining radioactive isotopes such as nickel-56 and nickel-57, along with stable elements including manganese and nickel, the team was able to constrain the masses and metallicities of the progenitor stars behind these supernovae and remnants, according to Kavli IPMU. The researchers then fed their models into a galactic chemical evolution simulation to test how this proposed explosion channel would shape the chemical makeup of the galaxy over time. Their results indicated that a non-zero fraction of Type Ia supernovae triggered by primordial black holes is needed to explain the chemical abundance trend observed among Milky Way stars, according to Kavli IPMU.
Leung, an assistant professor at SUNY Polytechnic Institute and a visiting associate scientist at Kavli IPMU, said the findings offer an indirect way to study objects that cannot be observed directly. “Our work suggests that some supernova that we observe in the sky could be a result of the PBHs. Therefore, even though we cannot directly observe these evasive entities, they leave many interesting clues in nature for us to probe their properties,” Leung said, according to Kavli IPMU and independently confirmed in identical wording by ScienceDaily and Universe Today.
The study’s co-authors include Ken’ichi Nomoto, a Kavli IPMU Visiting Senior Scientist, and Alexander Kusenko, a Kavli IPMU Senior Fellow, according to Kavli IPMU; Kusenko is based at UCLA, according to Phys.org. The team also includes Tomoharu Suzuki of Chubu University and Seth Walther, a SUNY Poly undergraduate who joined the project in summer 2024 through the school’s Summer Undergraduate Research Program and applied the model’s nucleosynthetic yields to the galactic chemical evolution calculations, according to Phys.org.
The paper’s abstract also notes that the diversity of explosion models from this channel “can reconcile with the empirical Phillips relation,” the relationship astronomers use to standardize Type Ia supernovae as cosmic distance indicators, according to arXiv. The team’s first paper on the topic was published as Leung et al., Astrophysical Journal 991, 11 (2025), according to the same arXiv preprint.
What We Don’t Know
Primordial black holes themselves remain entirely hypothetical — no PBH has ever been directly detected, and their existence as a dark matter component is unconfirmed. The researchers’ conclusions rest on comparing simulated explosion signatures against existing observational data rather than on any direct detection of a PBH-triggered event. The study also does not establish what fraction of all Type Ia supernovae might originate from this channel versus the conventional binary-star pathway, only that a non-zero contribution appears necessary to match observed chemical trends, according to Kavli IPMU.
The researchers say they plan to expand the work further by studying how PBH-triggered explosions might affect the overall population of conventional supernovae and the combined rates of these transient events, according to Kavli IPMU.