Astronomers Map a New Type of Stellar Explosion, Bridging Physics Gap
Researchers analyzing a nearby supernova have found the first clear evidence of how different explosion types in a class called Type Iax connect to each other—a discovery that could refine models used to measure cosmic distances and understand stellar evolution. The findings help physicists predict which white dwarfs will explode and how, information relevant to improving astronomical surveys worth billions in funding.
Originaltitel: Photometry and Spectroscopy of SN 2024pxl: A Luminosity Link among Type Iax Supernovae
<p>We present extensive ultraviolet to optical photometric and optical to near-infrared (NIR) spectroscopic follow-up observations of the nearby intermediate-luminosity (<em>M</em><sub><em>V</em></sub> = −16.81 ± 0.19 mag) Type Iax supernovae (SNe Iax) 2024pxl in NGC 6384. SN 2024pxl exhibits a faster light curve than the high-luminosity members of this class, and slower than low-luminosity events. The observationally well-constrained rise time of ∼11 days and an estimated synthesized <sup>56</sup>Ni mass of 0.03 <em>M</em><sub>⊙</sub>, based on analytical modeling of the integrated spectral energy distribution light curve, are consistent with models of the weak deflagration of a carbon-oxygen white dwarf. Our optical spectral sequence of SN 2024pxl shows weak Si ii lines and spectral evolution similar to other high-luminosity SNe Iax, but also a prominent early-time C ii line, like lower-luminosity SNe Iax. The late-time optical spectrum of SN 2024pxl closely matches that of SN 2014dt, and its NIR spectral evolution aligns with that of other well-studied, high-luminosity SNe Iax. The spectral-line expansion velocities of SN 2024pxl are at the lower end of the SNe Iax velocity distribution, and the velocity distribution of iron-group elements compared to intermediate-mass elements suggests that the ejecta are mixed on large scales, as expected in pure deflagration models. SN 2024pxl exhibits characteristics intermediate between those of high-luminosity and low-luminosity SNe Iax, further establishing a link across this diverse class.</p>