Reuniting Clusters with Gaia EDR3

We developed a novel method to reconstruct and determine the ages of all the young clusters within 200 pc of the Sun using Gaia EDR3 including the Pleiades (2110.03837) and four other clusters (2110.04296). In the process we found two white dwarfs lost from the Pleiades (2110.03837) bringing the total number of Pleiad WDs to three and three from the Alpha Persei cluster (2110.09668). These are the most massive white dwarfs to have been associated with clusters using the unprecedentedly precise astrometry of Gaia.

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The Smallest White Dwarf

This illustration shows the white dwarf ZTF J190132.9+145808.7 and the Moon. Image credit: Giuseppe Parisi.

Alumna Ilaria Caiazzo led a team based at Caltech and elsewhere to discover the smallest and therefore most massive white dwarf ever found. It is within about one percent of the maximum mass that a white dwarf can be, the Chandrasekhar mass. It rotates every seven minutes and harbours a magnetic field more than a billion times stronger than Earth’s (10.1038/s41586-021-03615-y).

References

A Large Fraction of Intermediate Mass Stars Become Magnetic White Dwarfs

About ten to twenty percent of white dwarfs are strongly magnetized, and the origin of the magnetic field is a mystery. We have taken a big step toward solving this mystery with the discovery that more than half of stars with initial masses between five and seven times that of the Sun form magnetic white dwarfs through single-star evolution. This is the first evidence that neither mergers or mass transfer are needed to build the strong fields on white dwarfs. Check out our ApJ paper (10.3847/2041-8213/abb5f7)!

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