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Dhillon, V.S. orcid.org/0000-0003-4236-9642, Kennedy, M.R., Breton, R.P. et al. (16 more authors) (2022) Multi-colour optical light curves of the companion star to the millisecond pulsar PSR J2051−0827. Monthly Notices of the Royal Astronomical Society, 516 (2). stac2357. pp. 2792-2800. ISSN 0035-8711
Abstract
We present simultaneous, multi-colour optical light curves of the companion star to the black-widow pulsar PSR J2051−0827, obtained approximately 10 years apart using ULTRACAM and HiPERCAM, respectively. The ULTRACAM light curves confirm the previously reported asymmetry in which the leading hemisphere of the companion star appears to be brighter than the trailing hemisphere. The HiPERCAM light curves, however, do not show this asymmetry, demonstrating that whatever mechanism is responsible for it varies on timescales of a decade or less. We fit the symmetrical HiPERCAM light curves with a direct-heating model to derive the system parameters, finding an orbital inclination of 55.9+4.8−4.1 degrees, in good agreement with radio-eclipse constraints. We find that approximately half of the pulsar’s spin-down energy is converted to optical luminosity, resulting in temperatures ranging from approximately 5150+190−190 K on the day side to 2750+130−150 K on the night side of the companion star. The companion star is close to filling its Roche lobe (fRL=0.88+0.02−0.02) and has a mass of 0.039+0.010−0.011 M⊙, giving a mean density of 20.24+0.59−0.44 g cm−3 and an apsidal motion constant in the range 0.0036 < k2 < 0.0047. The companion mass and mean density values are consistent with those of brown dwarfs, but the apsidal motion constant implies a significantly more centrally-condensed internal structure than is typical for such objects.
Metadata
Item Type: | Article |
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Authors/Creators: |
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Copyright, Publisher and Additional Information: | © Year Copyright holder. This is an author-produced version of a paper subsequently published in Monthly Notices of the Royal Astronomical Society. Uploaded in accordance with the publisher's self-archiving policy. |
Keywords: | stars: neutron; pulsars: individual: PSR J2051−0827 |
Dates: |
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Institution: | The University of Sheffield |
Academic Units: | The University of Sheffield > Faculty of Science (Sheffield) > Department of Physics and Astronomy (Sheffield) |
Depositing User: | Symplectic Sheffield |
Date Deposited: | 01 Sep 2022 15:46 |
Last Modified: | 19 Nov 2022 01:36 |
Status: | Published |
Publisher: | Oxford University Press (OUP) |
Refereed: | Yes |
Identification Number: | 10.1093/mnras/stac2357 |
Open Archives Initiative ID (OAI ID): | oai:eprints.whiterose.ac.uk:190537 |
Available Versions of this Item
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Multi-colour optical light curves of the companion star to the millisecond pulsar PSR J2051-0827. (deposited 01 Sep 2022 15:31)
- Multi-colour optical light curves of the companion star to the millisecond pulsar PSR J2051−0827. (deposited 01 Sep 2022 15:46) [Currently Displayed]