NGC 362D discovery reveals youngest white dwarf in pulsar system

An international research team, led by the National Institute for Astrophysics (INAF) and the University of Bologna, has identified two significant milestones regarding the binary star system NGC 362D. The study, published in Astronomy & Astrophysics Letters, focuses on a millisecond pulsar—a neutron star rotating hundreds of times per second—and its companion.

The research identifies the companion as the youngest white dwarf ever detected in a system with a millisecond pulsar. Specifically, it is a helium proto-white dwarf with a mass approximately 0.18 times that of the Sun. Scientists estimate that the transfer of matter between the two stars concluded roughly 600 million years ago, allowing astronomers to observe a rare, early phase of stellar evolution before the star reaches its typical cooling stage.

Additionally, observations revealed that the young white dwarf emits less ultraviolet light than current models predict. Researchers hypothesize that circumstellar material left over from the previous mass transfer process may be absorbing some of the radiation.