Exploring PSR J0901-4046 as an ultra-slowly rotating neutron star versus a white dwarf
Abstract
The source PSR J0901-4046 shows a very long rotational period, of ≈ 75.88 s. In fact, its long period suggests that it could be a white dwarf. We examine the properties of the source and compare the outcomes under the hypotheses of the source being a highly magnetized white dwarf (B-WD) and neutron star. We find that assuming it to be a B-WD with a surface field ∼ 1010 G explains many properties, including its storage/rotational energy, explaining luminosity. On the contrary, the neutron star-based idea, particularly if examined under the conventional spin down mechanism, requires an unusually high surface magnetic field ≳ 1014 G, even exceeding 1016 G, depending on the obliquity angle and emission mechanism. The source also sits very close to AR Sco, a white dwarf pulsar, in the period and period-derivative plane. We suggest that the source is a B-WD. Along with AR Sco, it being a B-WD constrains the death line model. B-WD hypothesis alleviates the necessity of an unusually high magnetic field hindering pair production for PSR J0901-4046 under the neutron star hypothesis. We argue that some rotation-powered pulsars with extreme properties may possibly be white dwarfs rather than neutron stars.
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BibTeX
@misc{mukhopadhyay2026exploring,
title = {{Exploring PSR J0901-4046 as an ultra-slowly rotating neutron star versus a white dwarf}},
author = {Banibrata Mukhopadhyay and Nirupam Roy and Zenia Zuraiq and Chandrachur Chakraborty and A R Rao},
howpublished = {arXiv},
year = {2026},
month = oct,
doi = {10.48550/arxiv.2610.28741},
eprint = {2610.28741},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2610.28741},
}
RIS
TY - UNPB
TI - Exploring PSR J0901-4046 as an ultra-slowly rotating neutron star versus a white dwarf
AU - Banibrata Mukhopadhyay
AU - Nirupam Roy
AU - Zenia Zuraiq
AU - Chandrachur Chakraborty
AU - A R Rao
PY - 2026
DA - 2026/10/20
PB - arXiv
DO - 10.48550/arxiv.2610.28741
UR - https://arxiv.org/abs/2610.28741
AB - The source PSR J0901-4046 shows a very long rotational period, of ≈ 75.88 s. In fact, its long period suggests that it could be a white dwarf. We examine the properties of the source and compare the outcomes under the hypotheses of the source being a highly magnetized white dwarf (B-WD) and neutron star. We find that assuming it to be a B-WD with a surface field ∼ 10^10 G explains many properties, including its storage/rotational energy, explaining luminosity. On the contrary, the neutron star-based idea, particularly if examined under the conventional spin down mechanism, requires an unusually high surface magnetic field ≳ 10^14 G, even exceeding 10^16 G, depending on the obliquity angle and emission mechanism. The source also sits very close to AR Sco, a white dwarf pulsar, in the period and period-derivative plane. We suggest that the source is a B-WD. Along with AR Sco, it being a B-WD constrains the death line model. B-WD hypothesis alleviates the necessity of an unusually high magnetic field hindering pair production for PSR J0901-4046 under the neutron star hypothesis. We argue that some rotation-powered pulsars with extreme properties may possibly be white dwarfs rather than neutron stars.
ER -