A stellar odd couple at an unusual stage of evolution
Most of the stars in the Milky Way are what we might call normal stars. They're main sequence stars like our sun, meaning they're doing what most people probably think stars do: shining as they fuse hydrogen atoms into helium atoms on a vast scale.
In a groundbreaking discovery, researchers from Italy and Germany have identified a millisecond pulsar, NGC 362D, in a unique stage of its evolution, accompanied by a very young white dwarf companion. This rare pairing is providing astronomers with a rare opportunity to study the aftermath of the recycling process, where a massive star's companion transfers mass to a neutron star, causing it to spin rapidly and form a pulsar.
The newly identified white dwarf, called COM-NGC 362D, is estimated to be only 0.18 times the mass of our Sun and is in the pre-cooling phase, indicating it is in the earliest stages of becoming a full-fledged white dwarf. This discovery is particularly significant because it is the youngest white dwarf companion to a millisecond pulsar ever detected.
The system was found by cross-referencing radio data from the pulsar with 10 years of Hubble observations in ultraviolet and near-infrared. The photometric properties of NGC 362D revealed significant wavelength-dependent variations in the ultraviolet light, suggesting the presence of a residual cloud of material surrounding the white dwarf. This material is believed to have been expelled during the mass-transfer phase, emphasizing the young age of the white dwarf.
This unique system offers astronomers a rare chance to study the post-recycling evolution of a white dwarf, allowing them to gain insights into the complex processes that shape the lives of these stellar odd-couples.
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- A Stellar Odd Couple at an Unusual Stage of Evolution universetoday.com
