The radius and magnetic field structure of the smallest white dwarf
Abstract
The white dwarf ZTF J1901+1458 is extreme in almost every regard: it rotates every 6.94 minutes, one of the shortest periods measured for an isolated white dwarf, it is threaded by a magnetic field of almost a billion Gauss, and is the smallest white dwarf for which a radius has been measured, with a size comparable to that of the Moon. The white dwarf is so compact, that it might be gravitationally unstable and headed toward collapse. The radius's measurement, however, hinges on assumptions on the white dwarf's spectral distribution that can only be verified by ultraviolet spectroscopy. Moreover, a UV spectrum will allow a detailed modeling of the white dwarf's magnetic field strength and morphology.
- Publication:
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HST Proposal
- Pub Date:
- June 2021
- Bibcode:
- 2021hst..prop16753C